December, 1940
UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
WILMON NEWELL, Director
GAINESVILLE, FLORIDA
PAPERWHITE
NARCI5
5U5
I. The Growth Cycle
II. Some Factors Affecting Bulb and Flower
Production
By R. D. DICKEY
Single copies free to Florida residents upon request to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA
Bulletin 353
BOARD OF CONTROL
H. P. Adair, Chairman, Jacksonville
W. M. Palmer, Oeala
R. H. Gore, Fort Lauderdale
N. B. Jordan, Quincy
T. T. Scott, Live Oak
J. T. Diamond, Secretary, Tallahassee
BRANCH STATIONS
NORTH FLORIDA STATION, QUINCY
J. D. Warner, M.S., Agron. Acting in
Charge
R, R. Kinkaid, Ph.D., Asso. Plant Path.
Elliott Whitehurst, B.S.A., Assistant An.
Husbandman
Jesse Reeves, Asst. Agron., Tobacco
CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Horticulturist in
Charge.
John H. Jefferies, Asst. in Cit. Breeding
Michael Peech, Ph.D., Soils Chemist
B. R. Fudge, Ph.D., Associate Chemist
W. L. Thompson. B.S., Associate
Entomologist
F. F. Cowart, Ph.D., Asso. Horticulturist
W. W. Lawless, B. S., Asst. Horticulturist
R. K. Voorhees, M.S., Asst. Plant Path.
EVERGLADES STA., BELLE GLADE
J. R. Neller, Ph.D., Biochemist in
Charge
J. W. Wilson, Sc.D., Entomologist
F. D. Stevens, B.S., Sugarcane Agron.
Thomas Bregger, Ph.D., Sugarcane
Physiologist
Frederick Boyd, Ph.D., Asst. Agronomist
G. R. Townsend, Ph.D., Plant Pathologist
R. W. Kidder, M.S., Asst. An. Husbandman
W. T. Forsee, Ph.D., Asso. Chemist
B S. Clayton, B.S.C.E., Drainage En-
gineer2
F. S. Andrews, Ph.D., Asso. Truck Hort.
SUB-TROPICAL STA., HOMESTEAD
W. M. Fifield, M.S., Horticulturist Act-
ing in Charge
S. J. Lynch, B.S.A., Asst. Horticulturist
Geo. D. Ruehle, Ph.D., Associate Plant
Pathologist
W. CENTRAL FLA. STA.,
BROOKSVILLE
W F. Ward, M.S., Asst. An. Husband-
man in Charges
FIELD STATIONS
Leesburg
M. N. Walker, Ph.D., Plant Pathologist
in Charge
K. W. Loucks, M.S., Assistant Plant
Pathologist
Plant City
A. N. Brooks, Ph.D., Plant Pathologist
Hastings
A. H. Eddins, Ph.D., Plant Pathologist.
E. N. McCubbin, Ph.D., Asso. Truck
Horticulturist
Monticello
Samuel 0. Hill, B.S., Asst. Entomologist'
Bradenton
Jos. R. Beckenbach, Ph.D., Truck Horti-
culturist in Charge
David G. Kelbert, Asst. Plant Pathologist
Sanford
R. W. Ruprecht, Ph.D., Chemist in
Charge, Celery Investigations
W. B. Shippy, Ph.D., Asso. Plant Path.
Lakeland
E. S. Ellison, Meteorologists
B. H. Moore, A.B., Asst. Meteorologist'
'Head of Department
'In cooperation with U.S.D.A.
'Cooperative, other divisions, U. of F.
EXECUTIVE STAFF
John J. Tigert, M. A., LL.D., President
of the University'
Wilmon Newell, D.Sc., Director8
Harold Mowry, M. S. A., Asst. Dir.,
Research
J. Francis Cooper, M.S.A., Editor'
Jefferson Thomas, Assistant Editors
Clyde Beale, A.B.J., Assistant Editor'
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Managers
K. H. Graham, Business Manager'
Rachel McQuarrie, Accountants
MAIN STATION, GAINESVILLE
AGRONOMY
W. E. Stokes, M.S., Agronomist'
W. A. Leukel, Ph.D., Agronomist'
Fred. H Hull, Ph.D., Agronomist
G. E. Ritchey, M.S., Associates
W. A. Carver, Ph.D., Associate
John P. Camp, M.S., Assistant
Roy E. Blaser, M.S., Assistant
Fred A. Clark, B.S.A., Assistant
ANIMAL INDUSTRY
A. L. Shealy, D.V.M., Animal Indus-
trialists
R. B. Becker, Ph.D., Dairy Husbandmans
E. L. Fouts, Ph.D.. Dairy Technologists
W. M. Neal, Ph.D. Asso. in An. Nutrition
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D.V.M., Veterinarian'
N. R. Mehrhof, M.Agr., Poultry Hus-
bandman'
W. G. Kirk, Ph.D., Asso. An. Husband-
man'
D. J. Smith, B.S.A., Asst. An. Husb.
P. T. Dix Arnold, M.S.A., Asst. Dairy
Husbandman3
L. .Rusoff, Ph. D., Asst. in An.
Nutrition3
0. W. Anderson, M.S., Asst. Poultry
Husbandman'
L. E. Mull, M.S., Asst. in Dairy Tech.
SOILS
R. V. Allison, Ph,D.. Chemist' 8
Gaylord M. Volk, M.S., Chemist
F. B. Smith, Ph.D., Microbiologists
C. E. Bell, Ph.D., Associate Chemist
H. W. Winsor, B.S.A., Assistant Chemist
J. Russell Henderson, M.S.A., Associates
L. H. Rogers, M.S., Asso. Biochemist
Richard A. Carrigan, B.S., Asst. Chemist
ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agricultural
Economist' 8
Zach Savage, M.S.A., Associate
A. H. Spurlock, M.S.A., Associate
ECONOMICS, HOME
Ouida D. Abbott, Ph.D., Home Econ-
omist'
Ruth Overstreet, R.N., Assistant
R. B. French, Ph.D., Asso. Chemist
ENTOMOLOGY
J. R. Watson, A.M., Entomologist'
A. N. Tissot, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant
HORTICULTURE
G. H. Blackmon, M.S.A., Horticulturist'
A. L. Stahl, Ph.D., Associate
F. S. Jamison, Ph. D., Truck Hort.'
R. J. Wilmot, M.S.A., Fumigation
Specialist
R. D. Dickey, M.S.A., Asst. Horticulturist
J. Carlton Cain, B.S.A., Assistant
Horticulturist
Victor F. Nettles, M.S.A., Assistant
Horticulturist
F. S. Lagasse, Ph.D., Horticulturist'
H. M. Sell, Ph.D., Asso. Horticulturist' -
PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist' '
George F. Weber, Ph.D., Plant Path.'
L. 0. Gratz, Ph.D., Plant Pathologist
Erdman West, M.S., Mycologist
Lillian E. Arnold, M.S., Asst. Botanist
PAPERWHITE NARCISSUS
By R. D. DICKEY
CONTENTS
Page Page
Cultural and Marketing Procedure.... 4 Effect of Size of Planting Stock Upon
I. Growth Cycle of Paperwhite Production of Marketable Bulbs_13
Narcissus Bulbs --......- 5 Factors Affecting Flower Production_.19
Experimental Studies --....-... .-. 7 Discussion -..... ...... ..... .......-.........22
II. Some Factors Bulb and Flower Summary ..----.~..-.... .....-................. 23
Production ... ---- ..13 Literature Cited .... ---- --..... .... ..... 24
INTRODUCTION
Several varieties of narcissus have been under cultivation
for many years in Florida, but the commercial industry as it
exists today had its beginnings in the early twenties. From a
meager start, it has increased until marketable bulbs sold total
several millions annually, as shown in Table 1.
The number of growers is not now so great as a few years
ago; however, the average number of bulbs produced per grower
has increase considerably (Table 1). This probably has been
due to a lessened demand and decreased price which has forced
many of the smaller growers out of production as it is necessary,
in most cases, to grow the bulbs in large quantities to show
a profit.
The principal commercial narcissus bulb growing areas in
the state are around Jacksonville, Doctor's Inlet, Green Cove
Springs, Penney Farms, Hastings and Daytona Beach.
The greater part of the narcissus marketed from Florida are
varieties belonging to the polyanthus group-Paperwhite, Chi-
nese Sacred and Grand Soleil d'Or. Varieties such as Grand
Monarque, Double Roman (Constantinople) and White Pearl are
grown to a limited extent. Of the first three mentioned, Paper-
white comprises a greater part of the total, so much so that it is
considered the standard in all discussion of narcissus types
among the growers, though, in general, the other varieties men-
tioned are handled in much the same way.
Acknowledgments-The author wishes to acknowledge his indebtedness
to Mr. W. V. Stephenson and Mr. J. Guille, who furnished the bulbs
used in this experiment, and to all bulb growers who so freely gave
information relative to their experience in narcissus growing.
1 Part of the material in this bulletin was presented to the Faculty of
the Graduate School of Cornell University in August, 1939, in partial
fulfillment of the requirements for the degree of master of science in
agriculture.
PAPERWHITE NARCISSUS
By R. D. DICKEY
CONTENTS
Page Page
Cultural and Marketing Procedure.... 4 Effect of Size of Planting Stock Upon
I. Growth Cycle of Paperwhite Production of Marketable Bulbs_13
Narcissus Bulbs --......- 5 Factors Affecting Flower Production_.19
Experimental Studies --....-... .-. 7 Discussion -..... ...... ..... .......-.........22
II. Some Factors Bulb and Flower Summary ..----.~..-.... .....-................. 23
Production ... ---- ..13 Literature Cited .... ---- --..... .... ..... 24
INTRODUCTION
Several varieties of narcissus have been under cultivation
for many years in Florida, but the commercial industry as it
exists today had its beginnings in the early twenties. From a
meager start, it has increased until marketable bulbs sold total
several millions annually, as shown in Table 1.
The number of growers is not now so great as a few years
ago; however, the average number of bulbs produced per grower
has increase considerably (Table 1). This probably has been
due to a lessened demand and decreased price which has forced
many of the smaller growers out of production as it is necessary,
in most cases, to grow the bulbs in large quantities to show
a profit.
The principal commercial narcissus bulb growing areas in
the state are around Jacksonville, Doctor's Inlet, Green Cove
Springs, Penney Farms, Hastings and Daytona Beach.
The greater part of the narcissus marketed from Florida are
varieties belonging to the polyanthus group-Paperwhite, Chi-
nese Sacred and Grand Soleil d'Or. Varieties such as Grand
Monarque, Double Roman (Constantinople) and White Pearl are
grown to a limited extent. Of the first three mentioned, Paper-
white comprises a greater part of the total, so much so that it is
considered the standard in all discussion of narcissus types
among the growers, though, in general, the other varieties men-
tioned are handled in much the same way.
Acknowledgments-The author wishes to acknowledge his indebtedness
to Mr. W. V. Stephenson and Mr. J. Guille, who furnished the bulbs
used in this experiment, and to all bulb growers who so freely gave
information relative to their experience in narcissus growing.
1 Part of the material in this bulletin was presented to the Faculty of
the Graduate School of Cornell University in August, 1939, in partial
fulfillment of the requirements for the degree of master of science in
agriculture.
PAPERWHITE NARCISSUS
By R. D. DICKEY
CONTENTS
Page Page
Cultural and Marketing Procedure.... 4 Effect of Size of Planting Stock Upon
I. Growth Cycle of Paperwhite Production of Marketable Bulbs_13
Narcissus Bulbs --......- 5 Factors Affecting Flower Production_.19
Experimental Studies --....-... .-. 7 Discussion -..... ...... ..... .......-.........22
II. Some Factors Bulb and Flower Summary ..----.~..-.... .....-................. 23
Production ... ---- ..13 Literature Cited .... ---- --..... .... ..... 24
INTRODUCTION
Several varieties of narcissus have been under cultivation
for many years in Florida, but the commercial industry as it
exists today had its beginnings in the early twenties. From a
meager start, it has increased until marketable bulbs sold total
several millions annually, as shown in Table 1.
The number of growers is not now so great as a few years
ago; however, the average number of bulbs produced per grower
has increase considerably (Table 1). This probably has been
due to a lessened demand and decreased price which has forced
many of the smaller growers out of production as it is necessary,
in most cases, to grow the bulbs in large quantities to show
a profit.
The principal commercial narcissus bulb growing areas in
the state are around Jacksonville, Doctor's Inlet, Green Cove
Springs, Penney Farms, Hastings and Daytona Beach.
The greater part of the narcissus marketed from Florida are
varieties belonging to the polyanthus group-Paperwhite, Chi-
nese Sacred and Grand Soleil d'Or. Varieties such as Grand
Monarque, Double Roman (Constantinople) and White Pearl are
grown to a limited extent. Of the first three mentioned, Paper-
white comprises a greater part of the total, so much so that it is
considered the standard in all discussion of narcissus types
among the growers, though, in general, the other varieties men-
tioned are handled in much the same way.
Acknowledgments-The author wishes to acknowledge his indebtedness
to Mr. W. V. Stephenson and Mr. J. Guille, who furnished the bulbs
used in this experiment, and to all bulb growers who so freely gave
information relative to their experience in narcissus growing.
1 Part of the material in this bulletin was presented to the Faculty of
the Graduate School of Cornell University in August, 1939, in partial
fulfillment of the requirements for the degree of master of science in
agriculture.
Florida Agricultural Experiment Station
TABLE 1.-Number of Growers and Annual Production of Bulbs in
Florida From 1927-28 to 1939-401.
Number of Number of
Year Growers Bulbs Harvested
1927-28 87 58,333,800
1928-29 147 81,954,400
1929-30 179 95,281,600
1930-31 212 128,965,050
1931-32 175 111,468,920
1932-33 100 87,716,000
1933-34 59 96,853,270
1934-35 45 82,002,300
1935-36 17 81,775,000
1936-37 11 94,597,000
1937-38 9 90,723,000
1938-39 11 86,090,000
1939-40 9 88,650,000
1 Data furnished by the State Plant Board.
Average No. Bulbs
Per Grower
670,503
557,510
532,299
608,326
636,965
877,160
1,641,158
1,822,273
4,810,294
8,599,727
10,080,333
7,826,363
9,850,000
An extensive survey of the commercial narcissus bulb in-
dustry revealed that general cultural practices employed by
growers, with the possible exception of certain phases of fertili-
zation, are quite similar. However, it was evident that a great
diversity of opinion exists in regard to many points and, doubt-
less, several of these may have a direct effect upon the number
of marketable bulbs produced per acre and consequently upon
the cost of production.
It is the purpose of this bulletin to report certain experi-
ments relative to: (1) Behavior of the different categories of the
bulbs in regard to the production of mother bulbs, double-nosed
bulbs, single-nosed round bulbs and slabs; (2) effect of size of
planting stock upon the production of marketable bulbs, and, (3)
factors affecting the production of flowers.
Although the experimental work herein reported deals en-
tirely with Paperwhite, it is thought that much of the experi-
mental evidence presented is applicable to the other varieties
grown commercially.
CULTURAL AND MARKETING PROCEDURE
Most growers, with some slight variations, employ approxi-
mately the same cultural practices. These, briefly, are: To dig
the bulbs upon maturity in the late spring and early summer and
immediately transport them to the storage shed. After they
have been in storage for several weeks and become completely
dry and cured they are cleaned and graded, sized, counted and
placed in the packing case. The remaining stock is planted back
in the field. This consists of mother bulbs and slabs of all sizes
Paperwhite Narcissus
and round bulbs that fail to make the marketable grades. These
are often mixed and are planted without any attempt at sorting.
Occasionally the different categories are kept separate during
the process of grading and are planted in different blocks. Plant-
ing time extends from September to early December.
To meet the requirements of the trade, a good percent of the
bulbs marketed must produce flowers. In order to insure this with
Paperwhite, it is necessary to sell round, firm, single-nosed bulbs
which are 12 centimeters and above in circumference, which
is the standard for marketable bulbs of this particular variety.
Much the same standard is used for the other varieties with the
exception that, with some, the bulbs may be somewhat angular,
which is not allowed for Paperwhite. With several the smallest
marketable grade is above the 12 centimeters indicated for Paper-
white, e. g., 14 centimeters for Grand Soleil d'Or.
It has been pointed out that the general practice is to plant
back all sizes of the different categories of bulbs excepting those
marketable ones sold. No more than a cursory examination of
the situation is necessary to show the necessity for information
relative to the percent of these smaller sizes which will even-
tually produce marketable bulbs and the time required for them
to do this.
Over a period of years the average annual cost of growing
an acre of bulbs will be approximately the same. Therefore the
economic success of the enterprise is dependent upon yield per
acre of marketable bulbs. It is evident that any factor which
has an effect upon this is of considerable importance.
I. 'Growth Cycle of Paperwhite Narcissus
Bulbs
In order to grow narcissus well it is essential that the grower
have in mind clearly the behavior of the different categories of
the bulbs. This is not necessarily a fixed procedure, varying con-
siderably with the different groups and varieties of bulbs, but
a general plan is followed which is quite uniform.
Griffith (5)2, using Golden Spur to illustrate the point, says
there "are four categories of bulbs; namely, splits, round, double-
nosed and mother bulbs", and that "in general it may be assumed
that one season's culture will transform one of these classes into
2 Italic figures in parentheses refer to "Literature Cited" in the back
of this bulletin.
Florida Agricultural Experiment Station
B C
Fig. 1.-Paperwhite bulbs; A, mother bulb with slabs; B, double-
noseed bulb; C, round bulb.
the next one above". He states that the reproduction in the
Paperwhite and Chinese sacred-lily is not essentially different
from that described above (Fig. 1).
Referring to the polyanthus varieties grown in Florida,
Brown (2) states, "When the mature round type of bulb is plant-
ed in the open field it should not only bloom well the first season,
but should grow and divide, often making two or three or more
:r,';-:
Paperwhite Narcissus
slabs". It is obvious that any round bulb which makes one or
more slabs will, in most instances, be classed as a mother bulb
(Fig. 1). If this happens, the growth cycle outlined by Griffith
(5) will be changed for a certain percentage of the bulbs. Furth-
more, Brown (2) says that mother bulbs will continue to produce
slabs indefinitely, and that some of the larger slabs will split again
instead of becoming round.
Hayward (7), referring to the polyanthus varieties grown
in Florida, states, "The 'round' bulbs are 'round' only one year,
becoming 'mother bulbs' and producing slabs in their turn ever
afterward".
Apparently the amount of plant nutrients given bulbs will
have an effect upon their growth cycle, as Parker (9) found that
the percentage of mother bulbs obtained from fertilized plots
was significantly higher than from the check plots. Biekart (1)
reported similar results.
It is evident that reports are at variance as to the behavior
of the different categories of the bulbs. Consequently, during
the course of these investigations data were obtained which give
considerable information on these points.
EXPERIMENTAL STUDIES
Materials and Methods.-The bulbs used to initiate this ex-
periment were grown at Green Cove Springs and Jacksonville,
which are representative commercial areas. They were selected
at random from large commercial stocks of Paperwhite which
were in storage in bulb sheds. The planting stock selected con-
sisted entirely of round bulbs which were graded into 6, 7, 8, 9,
10, 11, 12, 13 and ( centimeter sizes. Five hundred bulbs of
each size were planted, with the exception of the 6 and 15 centi-
meter sizes, which consisted of 350 and 465, respectively.
These bulbs and their subsequent increase were planted an-
nually on the Experiment Station farm at Gainesville from 1934
to 1938. They were grown in Alachua fine sand without irriga-
tion during 1934-35 and 1935-36 and the last two years in Arre-
dondo fine sandy loam because an overhead watering system
was available.
Each size was grown separately in rows 34 inches apart, the
bulbs having been planted according to standard methods. A
fertilizer mixture analyzing 6-10-10 was applied in the drill at
the time of planting at the rate of 2,000 pounds per acre. Flat
cultivation was practised as required.
Florida Agricultural Experiment Station
The bulbs were dug upon maturity each year, placed in trays
and stored in the barn loft. In the early fall they were care-
fully cleaned, graded and sized.
Data were ob-
S, trained relative
to their growth
cycle, subse-
quent produc-
tion of market-
able bulbs and
flower produc-
tion.
Slab s.-In-
formation was
needed as to
what categories
s *- of bulbs would
I.Aj be produced by
slabs of differ-
ent sizes. To ob-
t. tain this the
slabs were grad-
'.":"' ed into sizes
S,, h which ranged
f from 4 to 15
centimeters and
planted separ-
ately for a com-
k .parative study.
The results
Obtained are
given in Table
2. These data
Fig. 2.-Mother and round bulbs produced from show that some
slabs of 4, 5, 6, and 7 centimeter sizes as indicated of the slabs of
on the left. all sizes devel-
oped into round bulbs while others again formed slabs and
were therefore classed as mother bulbs (Figs. 2 and 3).
This varies with the size, as 82.9 percent of the 4 cetnimeter slabs
produced round bulbs while 46.0 percent of the 13 and 33.3 per-
cent of the 14 centimeter sizes functioned in a similar way (Ta-
ble 2).
Paperwhite Narcissus
Brown (2) has observed that some of the larger sized slabs
may split to form mother bulbs, which agrees with the results
0oo Hu. obtained in these tests.
0 However, the percent of
o0 smaller sizes that do this
70 is much larger than the
60 reports of other workers
a5o would indicate, and is
S- further evidence of the
desirability of culling out
the smaller sizes of all
categories as recom-
10 Imended elsewhere.
6 78 9 0 F iZ 11 Round Bulbs.-All 6 to
o100 Centimeters
RouNo BUL5es. 16 centimeter round
o9 bulbs were planted sep-
so ately and were graded
70 each year to determine
60 their performance with
0 o respect to their develop-
Ao40 ment into the different
3o categories (Fig. 4). The
20 data obtained are pre-
lo sented in Table 3.
0-. 7 1- 5 1- 6 Upon examination of
too Centimeters. this table it is evident
q0o that some of the round
8o bulbs do not split to form
70 slabs but remain round
o [- and are so graded (Fig.
50 I 3). This varies with the
S B size, as 59.9 percent of
Sthe 6 centimeter bulbs
Remained round while 5.3
Percent of the 13 and 0.8
0 percent of the 15 centi-
S. 1 ~ o ~ 2 ~ 3 4 is meter bulbs functioned
Certimeters. in a like manner (Fig. 3).
Fig. 3.-Percent of mother and round in a like maer (Fig. 3).
bulbs produced by mother bulbs (top), All bulbs of the 14 and
round bulbs and slabs. Light lines indicate 16 centimeter sizes split
mother bulbs; black lines, round bulbs. t
to form mother bulbs.
From the data presented it is apparent that there is a short-
10 Florida Agricultural Experiment Station
Fig. 4.-Mother and round bulbs produced from round bulbs of 6, 7
and 10 centimeter sizes as indicated on left.
ening of the cycle indicated by Griffith (5) and that only a por-
tion of the bulbs perform in the manner suggested by Brown
(2) and Hayward (7).
Mother Bulbs.-These bulbs were handled in the same man-
ner as previously described for ro d und bulbs. From the data
presented in Table 4 it is evident that a certain percent "round
up" and that the percent of bulbs which do this is proportional
Paperwhite Narcissus
_.
Fig. 5.-Mother and round bulbs produced from mother bulbs of 9,
10 and 11 centimeter sizes as indicated on the left.
to their size (Fig. 3). Of the 6 centimeter size, 36.5 percent be-
came round, while 6.6 percent of the 15 and none of the 16 centi-
meter sizes produced round bulbs (Fig. 3). They are indistin-
guishable from round bulbs originating from any other source,
therefore those that make the marketable grades would be sold
Florida Agricultural Experiment Station
TABLE 2.-Total Mother and Round Bulbs Produced Over a Three-
Year Period by Planting Slabs of Different Sizes.
Sizes Bulb Types Graded
Cm. Number Number Percent
Planted Graded Lost Total
41 2,896 2,572 11.2 2,572
5 3,121 2,839 9.0 2,839
6 4,997 4,520 9.6 4,520
7 6,438 5,858 9.0 5,858
8 6,293 5,673 9.9 5,673
9 3,369 3,041 9.7 3,041
10 2,390 2,186 8.5 2,186
11 1,152 1,013 12.1 1,013
12 247 186 24.7 186
13 74 63 14.9 63
14 24 21 12.5 21
15 3 2 33.3 2
1 Four centimeters and below.
Mother Bulbs Round Bulbs
Total Percent Total Percent
439 17.1 2,133 82.9
422 14.9 2,417 85.1
826 18.3 3,694 81.7
1,297 22.1 4,561 77.9
1,182 20.8 4,491 79.2
511 16.8 2,530 83.2
415 19.0 1,771 81.0
266 26.3 747 73.7
79 42.5 107 57.5
34 54.0 29 46.0
14 66.7 7 33.3
1 50.0 1 50.0
(Fig. 5). The proportion of mother bulbs to round bulbs pro-
duced each year varies somewhat with all sizes, except 16 centi-
meters, which is not considered, as in only one year were bulbs
of this size obtained.
From the data presented it is evident that a certain percent
of the mother bulbs do not function in the manner indicated by
Brown (2) and Hayward (7).
Double-Nosed Bulbs.-It was soon evident that the number
of bulbs which would fall in this category was very small, and
therefore no record was kept as to the production of this type.
All bulbs determined as belonging to this classification were
graded as mother bulbs throughout the experiment.
TABLE 3.-Total Mother and Round Bulbs Produced Over the Four-
Year Period by Planting Round Bulbs of Different Sizes.
Sizes Bulb Types Graded
Cm. Number Number Percent Mother Bulbs Round Bulbs
Planted Graded Lost Total Total Percent Total Percent
61 915 789 13.8 789 317 40.1 472 59.9
7 1,201 1,108 7.8 1,108 615 55.5 493 44.5
8 1,946 1,784 8.3 1,784 1,315 73.7 469 26.3
9 2,211 2,005 9.3 2,005 1,632 81.4 373 18.6
10 2,902 2,615 9.9 2,615 2,351 89.9 264 10.1
11 2,957 2,588 12.5 2,588 2,375 91.8 213 8.2
12 1,832 1,690 7.8 1,690 1,552 91.8 138 8.2
13 1,484 1,378 7.1 1,378 1,305 94.7 73 5.3
14 281 273 2.8 273 273 100.0 0 0.0
15 521 481 7.7 481 477 99.2 4 0.8
16 10 10 0.0 10 10 100.0 0 0.0
1 Six centimeters and below.
Paperwhite Narcissus
In grading the bulbs of the 1937-38 season, several thousand
round bulbs were examined and, of this number, no more than a
dozen could be classed as double-nosed. In November, 1938, 579 10
to 16 centimeter round bulbs were planted which had developed
from slabs during the previous growing season. If the growth cy-
cle outlined by Griffith (5) was followed, all should have formed
double-nosed bulbs. However, when dug in June, 1939, it was
found that 571 mother bulbs and eight round bulbs had been
produced but that none were double-nosed.
TABLE 4.-Total Mother and Round Bulbs Produced Over a Three-
Year Period by Planting Mother Bulbs of Different Sizes.
Sizes Bulb Types Graded
Cm. Number Number Percent Mother Bulbs Round Bulbs
Planted Graded Lost Total Total Percent Total Percent
61 319 255 20.1 255 162 63.5 93 36.5
7 500 444 11.2 444 351 79.1 93 20.9
8 1,418 1,316 7.2 1,316 1,211 92.0 105 8.0
9 1,631 1,488 8.8 1,488 1,357 91.2 131 8.8
10 2,770 2,530 8.7 2,530 2,324 91.9 206 8.1
11 2,866 2,673 6.7 2,673 2,440 91.3 233 8.7
12 1,675 1,525 9.0 1,525 1,398 91.7 127 8.3
13 1,524 1,418 7.0 1,418 1,337 94.3 81 5.7
14 561 514 8.4 514 495 96.3 19 3.7
15 163 152 6.7 152 142 93.4 10 6.6
16 88 83 5.7 83 83 100.0 0 0.0
1 Six centimeters and below.
II. Some Factors Affecting Bulb and Flower
Production
EFFECT OF SIZE OF PLANTING STOCK UPON PRODUC-
TION OF MARKETABLE BULBS
Experimental Studies.-In Table 5 are given the size and num-
ber of salable bulbs produced by the original planting stock
through four seasons. It will be noted that there is a great dif-
ference in this respect, as the 15-centimeter size produced
approximately 12 times as many marketable bulbs and compara-
tively more of the larger grades than did the 6-centimeter size.
This is an important point because there is a decided differential
in price between different grades. For example, the price per
thousand for 15 centimeter bulbs may be twice that obtained for
12 centimeter bulbs. There is comparatively little increase in the
total number of salable bulbs produced by the 7, 8 and 9 centi-
meter sizes; however, the increase is rapid from this size up, as
the 10 and 11-centimeter sizes produce, respectively, approxi-
mately four and nine times as many bulbs (Fig. 6).
Paperwhite Narcissus
In grading the bulbs of the 1937-38 season, several thousand
round bulbs were examined and, of this number, no more than a
dozen could be classed as double-nosed. In November, 1938, 579 10
to 16 centimeter round bulbs were planted which had developed
from slabs during the previous growing season. If the growth cy-
cle outlined by Griffith (5) was followed, all should have formed
double-nosed bulbs. However, when dug in June, 1939, it was
found that 571 mother bulbs and eight round bulbs had been
produced but that none were double-nosed.
TABLE 4.-Total Mother and Round Bulbs Produced Over a Three-
Year Period by Planting Mother Bulbs of Different Sizes.
Sizes Bulb Types Graded
Cm. Number Number Percent Mother Bulbs Round Bulbs
Planted Graded Lost Total Total Percent Total Percent
61 319 255 20.1 255 162 63.5 93 36.5
7 500 444 11.2 444 351 79.1 93 20.9
8 1,418 1,316 7.2 1,316 1,211 92.0 105 8.0
9 1,631 1,488 8.8 1,488 1,357 91.2 131 8.8
10 2,770 2,530 8.7 2,530 2,324 91.9 206 8.1
11 2,866 2,673 6.7 2,673 2,440 91.3 233 8.7
12 1,675 1,525 9.0 1,525 1,398 91.7 127 8.3
13 1,524 1,418 7.0 1,418 1,337 94.3 81 5.7
14 561 514 8.4 514 495 96.3 19 3.7
15 163 152 6.7 152 142 93.4 10 6.6
16 88 83 5.7 83 83 100.0 0 0.0
1 Six centimeters and below.
II. Some Factors Affecting Bulb and Flower
Production
EFFECT OF SIZE OF PLANTING STOCK UPON PRODUC-
TION OF MARKETABLE BULBS
Experimental Studies.-In Table 5 are given the size and num-
ber of salable bulbs produced by the original planting stock
through four seasons. It will be noted that there is a great dif-
ference in this respect, as the 15-centimeter size produced
approximately 12 times as many marketable bulbs and compara-
tively more of the larger grades than did the 6-centimeter size.
This is an important point because there is a decided differential
in price between different grades. For example, the price per
thousand for 15 centimeter bulbs may be twice that obtained for
12 centimeter bulbs. There is comparatively little increase in the
total number of salable bulbs produced by the 7, 8 and 9 centi-
meter sizes; however, the increase is rapid from this size up, as
the 10 and 11-centimeter sizes produce, respectively, approxi-
mately four and nine times as many bulbs (Fig. 6).
Florida Agricultural Experiment Station
The extremely low yield of marketable bulbs for 1937-38
was due to unfavorable environmental conditions and the late-
ness of planting. Severe reduction in foliage area by cold follow-
ed immediately by an extremely dry spring seriously curtailed
growth and resulted in the production of a very few bulbs of
marketable size. Undoubtedly, the total number of salable bulbs
produced by each size of planting stock would have been con-
siderably greater over the four seasons had this been a normal
growing year; however, it is thought that the ratio between them
would not have been materially affected.
370
360
350
340
330
o0 -
320
310
300
ZO.
Z80
Z70
260
260
Z40
230
220
200 .
SZOO
180
50
(so.
I I40 *
100.
so
70
5IZ2 OF ORIGINAL PlANTING STOCK
Fig. 6.-Number of different sizes of marketable
the original planting stock (lower figures).
13 15
bulbs produced by
Commercial plantings are from time to time subjected to
similar conditions but, in many instances, irrigation facilities
enable growers to alleviate the drought conditions; yet there
are occasional years, such as the extremely dry season of 1937-38,
when some growers may not dig their bulbs. This was because of
Paperwhite Narcissus
TABLE 5.-Size and Number of Bulbs of Commercial Grades Produced
Over the Four-Year Period From Bulbs of Different Sizes.
Size and Num- Size Total Four- Percent
ber of Origmal in 1934-35 1935-36 1936-37 1937-382 Year Each Size
Planting Stock cm. No. No. No. No. Total of Total
Bulbs Bulbs Bulbs Bulbs
48.7
41.0
10.3
lHad 500 6-centimeter and 500 15-centimeter bulbs been used. there
would have been produced approximately 57 and 683 salable bulbs for
these sizes.
2Extremely low yield due to unfavorable weather conditions.
350-6 cm.1 12 0 4 14 1 19
13 0 3 11 2 16
14 0 0 4 0 4
Totals 0 7 29 3 39
500-7 cm. 12 0 10 23 5 38
13 0 0 26 1 27
14 0 0 1 0 1
15 0 1 1 1 3
Totals 0 11 51 7 69
500-8 cm. 12 0 6 29 4 39
13 0 0 25 3 28
14 0 0 11 0 11
15 0 0 2 0 2
Totals 0 6 67 7 80
500-9 cm. 12 5 11 74 14 104
13 0 2 36 1 39
14 0 0 9 0 9
15 0 0 2 0 2
Totals 5 13 121 15 154
500-10 cm. 12 25 12 103 8 148
13 0 8 55 1 64
14 0 1 9 0 10
15 0 1 1 0 2
Totals 25 22 168 9 224
500-11 cm. 12 82 34 134 22 272
13 58 26 87 8 179
14 7 1 26 0 34
15 0 0 6 0 6
16 0 0 1 1 2
Totals 147 61 254 31 493
500-12 cm. 12 33 43 147 14 237
13 79 30 115 4 228
14 17 1 43 1 62
15 0 2 8 0 10
Totals 129 76 313 19 537
500-13 cm. 12 17 88 100 35 240
13 35 91 105 12 243
14 7 38 41 2 88
15 0 7 17 0 24
16 0 3 2 0 5
Totals 59 227 265 49 600
465-15 cm.1- 12 0 201 134 33 368
13 2 97 94 13 206
14 1 14 47 0 62
15 0 2 6 1 9
16 1 0 3 0 4
Totals 4 314 284 47 649
Florida Agricultural Experiment Station
the poor increase in size and the subsequent failure of the devel-
opment of a sufficient number of bulbs of salable grades.
Since the only variable, other than the exceptions previously
noted, was the original difference in size of planting stock, this
may be considered as the reason for the differences in the number
of marketable bulbs produced (Table 5).
Potentially, the marketable bulbs may come from mother
bulbs and slabs of all sizes, and round bulbs from 11 centimeters
and below-all round bulbs 12 centimeters and above are sal-
able.
The data presented in Table 6 and Figure 7 show that a
certain percent of the round bulbs derived from the various
sizes of slabs fail to reach the marketable grades. Furthermore,
these data show that the size of the round bulbs produced varied
directly with the sizes of the planting stock. The data for round
bulbs derived from mother bulbs and round bulbs were found to
be similar to those given for slabs. The larger the size _of the
original planting stock (Table 5 and Figure 6), the greater the
39
31
3 -
25
34
29
SCentimeter s.
5i35 o(.S65br Planted
Fig. 7.-Percent of each size of.round bulbs produced from slabs
2 79
Centimeters.
Fig. 7.-Percent of each size of round bulbs produced from slabs
of different sizes for 1935-36 and 1936-37. Lower figures are sizes
of slabs planted.
TABLE 6.-Size, Number and Percent of Round Bulbs Produced from Slabs of Different Sizes for 1935-36 and 1936-37.
Size of Round Bulbs Produced-in Centimeters
Sizes of
Slab Planted 4 5 6 7 8 9 10 11 12 13 14 15 16
Cm. Num- No. Per- No. Per- No. Per- No. Per- No. Per- No. Per- No. Per- No. Per- No. Per- No. Per- No. Per- No. Per- No. Per-
ber cent cent cent cent cent cent cent cent cent cent cent cent cent
121 23.4 115 22.2
18 3.9 39 8.6
11 1.1
144 27.9
88 19.3
59 6.1
17 0.9
)1 19.5
40 30.7
31 16.6
32 5.7
32 1.4
4 0.3
3 0.3
6.2 4 0.8
23.0 45 9.9 21 4.6
34.6 240 24.8 137 14.2
20.2 522 28.9 538 29.8
8.2 327 14.8 720 32.6
2.3 96 6.8 311 22.0
0.6 33 3.1 129 12.0
0.2 9 1.5 43 7.4
1 1.0 8 7.8
1 3.7 2 7.4 5 18.5 6 22.2 7 25.9 4 14.8 2 7.4
ICombined because of small number of the 14-centimeter size.
4 517
5 456
6 968
7 1805
8 2211
9 1414
10 1073
11 583
12 102
13 and
141 27
1 0.1
26 1.4
183 8.3
272 19.2
308 28.7
184 31.6
27 26.5
10 0.6
47 2.1
141 10.0
196 18.3
171 29.3
26 25.5
1 0.1
1 0.2
1 1.0
Florida Agricultural Experiment Station
number of marketable bulb produced over the period of the
experiment, due to a higher production of the larger sizes of all
categories (slabs, mother bulbs and round bulbs) from which
round bulbs are produced (Table 7).
TABLE 7.-Size and Number of Slabs Produced by the Original
Planting Stock Over a Three-Year Period.
Size and No.
of Original Sizes Produced
Planting Stock
4 5 6 7 8 9 10 11 12 13 14 15
cm. cm. cm. cm. cm. cm. cm. cm. cm. cm. cm. cm.
350- 6 cm. 77 207 228 291 223 93 37 6 2 1 .---
500- 7 cm. 235 258 460 559 394 136 48 22 2 2 1
500- 8 cm. 154 327 589 541 361 92 49 7 -- ---
500- 9 cm. 383 429 581 672 415 167 76 15 1--- -----
500-10 cm. 534 464 636 761 743 353 178 84 12 8 ---
500-11 cm. 747 521 733 930 947 475 319 147 21 9 6 .
500-12 cm. 589 430 709 901 1021 613 444 239 56 9 1 1
500-13 cm. 150 324 634 805 1026 578 489 268 91 36 10 1
465-15 cm. 27 161 427 978 1163 862 750 364 62 10 5 1
It has been stated that growers commonly plant back, year
after year, all sizes of the different categories of bulbs, other than
those which are sold. From the data presented it can be seen that
many of the smaller sizes never make bulbs of marketable grades,
which is a very important point because of its effect upon the
economic success of the enterprise. Obviously it is unnecessary
and expensive continually to plant large numbers of bulbs from
which comparatively few salable bulbs will be obtained, yet this
is often done. From the data presented, the need for considerable
culling of the smaller sizes of all categories is evident.
It is apparent that any factor which would affect, either
favorably or unfavorably, the growth of narcissus would, in a
like degree, affect the production of marketable bulbs. The effect
of unfavorable environmental conditions such as moisture and
temperature has been mentioned. Time of planting may have an
effect upon growth and, therefore, upon the production of salable
bulbs, though no experimental evidence is available relating
directly to Florida conditions.
Parker (9), working in Virginia with the King Alfred nar-
cissus, found that the number of round bulbs produced from
fertilized planting stock was less than that from the non-fertilized
stock. This was attributed to an increase in the formation of
mother bulbs which is accompanied by a decrease in the number
of round bulbs.
Paperwhite Narcissus
In experiments with Paperwhite narcissus conducted under
greenhouse conditions in New Jersey, Biekart (1) found that
bulbs receiving the largest amounts of nitrogen in the field
produced the greatest percent of mother bulbs
FACTORS AFFECTING FLOWER PRODUCTION
In the earlier development of the narcissus bulb industry in
Florida and other sections of the United States, Griffith (4) states
that a great deal of complaint was registered, with considerable
basis, regarding the stocks of Paperwhite. He says, "The real
trouble has been lack of knowledge of what constitutes good
stock. In one case a grower deliberately selected his largest bulbs
with two to four or more noses to send to the florist. They were
selected from stock left in the ground three years. When forced,
these bulbs produced four or more shoots each and but little
blossom. The bulbs of smaller size which this grower planted for
propagation flowered well, and similar bulbs that were single-
nosed sent to another florist were pronounced good".
This difficulty has been overcome by a better knowledge of
what constitutes a good marketable bulb. The standard now em-
ployed for Paperwhite is: A round, firm, single-nosed bulb 12
centimeters or larger in circumference. The above would indicate
that both size and category of bulb will affect the percent that
will bloom and the quality of the spike produced.
Parker (9), working with King Alfred narcissus, found that
the immediate effect of fertilizer treatment was to reduce some-
what the percent of bulbs that would bloom. However, he found
that fertilization does eventually slightly improve the quality of
the bloom.
Emsweller, Randall and Weaver (3), in a progress report of
work done in North Carolina with 'King Alfred narcissus,
obtained no significant differences in flower production from
experiments testing the time, rate and method of fertilizer appli-
cation. With the exception of two plots, only those receiving
boron as part of their fertilizer treatment were found to have
significantly greater flower yields than the plots which received
no boron. It is suggested that the results indicate a stimulation
by boron of new growth centers in the bulbs.
The work of Griffith (6), Lumsdon (8), Whiteman (10) and
others shows that the temperature at which narcissus bulbs are
stored has an effect upon their flower production.
It is obvious that the environmental conditions to which
Florida Agricultural Experiment Station
narcissus bulbs are subjected have a decided influence upon
their flowering response.
Experimental Studies.-During the first year of the experi-
ment, general notes were kept on flower production and these
are given below:
Number and Size Flower
of Bulbs Production
350- 6 cm. No bloom
500- 7 cm. No bloom
500- 8 cm. No bloom
500- 9 cm. 14 bloom spikes produced
500-10 cm. Light bloom
500-11 cm. Medium quantity of bloom
500-12 cm. Heavy bloom
500-13 cm. Heavy bloom
465-15 cm. Very heavy bloom
It is evident that the number of bloom spikes produced
varies considerably, depending upon the size of the bulb.
For the next three seasons, 1935-1938, detailed records were
kept of flower production of all sizes and categories of bulbs.
The data obtained are presented in Table 8 and illustrated
graphically in Fig. 8.
From examination of these data, it will be seen that both
size and category of bulb has a decided effect upon flower yield.
TABLE 8.-Flowers Produced by Bulbs of Different
Categories From 1935 to 1938.
Sizes in Various
Mother Bulbs
o o .
*sn K ti
3191
500
1,418
1,631
2,770
2,866
1,675
1,524
561
163
88
0
1
159
524
1,057
1,210
850
942
412
124
73
0.0
0.5
11.2
32.1
38.2
42.2
50.7
61.8
73.4
76.1
83.0
Round Bulbs
W
.0
6. 6
Z, ZrX4 PrS
S~ d3'
SRrt fQ.H +^.P
5651
701
1,446
1,711
2,402
2,457
1,332
984
281
56
10
0
3
215
717
1,117
1,717
999
820
272
56
10
0.0
0.4
14.9
41.9
46.5
69.9
75.0
83.3
96.8
100.0
100.0
Slabs
.0,i~f fi
2,8962
3,121
41.997
6,-138
6,293
3,369
2,390
1,152
247
74
24
3
0.0
0.0
0.0
0.0
0.08
0.2
0.8
1.8
6.9
20.3
37.5
33.3
iSix centimeters and below.
2Four centimeters and below.
Size
(cm.)
~ I
Paperwhite Narcissues
1oo
95
85
80
75
70
65
60
30
25
20
15
t0
5
6 7 9 10 1 121314 1516 6 7 8 10 II 121314 156 4 7 8 9 10 1112 1314 15
Centimeters Centimeters Centimeters
MOTHER BULBS ROUND BUL.B5 SLABs
Fig. 8.-Percent of bulbs which flowered of the different sizes of
bulb categories.
No blooms were produced by the 6 centimeter mother bulbs,
while 0.5 percent of the 7 and 83.0 percent of the 16 centimeter
bulbs flowered. The percent of bulbs which produced flowers
increased with the size of the bulbs.
Much the same thing was true for round bulbs, with the
exception that, for each size, the percent of bulbs that bloom is
consistently greater than with the mother bulbs.
No flowers were produced by the 4 to 7 centimeter slabs and
a very small percent by those of 8 to 12 centimeters, but from
this size up there was considerable increase in the percent of
slabs producing blooms.
It has been pointed out that in each category the percent of
bulbs that bloom varies directly with the size. Likewise, it is
Florida Agricultural Experiment Station
evident that bulb category has a decided effect upon the bulb's
ability to bloom and that the greatest difference is between the
slabs and mother and round bulbs.
DISCUSSION
Throughout this experiment all determinations of bulb cate-
gory were on the basis of visual morphological appearance at
time of grading. A similar standard has been used by other
workers, therefore the results reported here should be compar-
able where a specific variety is concerned.
The mother bulbs in some instances became round, and the
data presented show that the percent which performed in this
manner was proportional to their size. They were not unlike
round bulbs which came from other categories of planting stock,
yet all of them did not meet the complete standard for market-
able Paperwhites, as some were found to be multiple-nosed when
cut open for internal examination. From the external appearance
it was impossible to detect this and, in commercial practice, the
same thing doubtless would occur and therefore all bulbs in this
classification would be offered in the trade along with other
round types. Much the same condition probably would have been
found in the round bulbs which remained round for more than
one year, and some of the single-nosed rounds that developed
from slabs the previous season, but it seemed likely that a
smaller percent of the bulbs in this category would be found
which had so developed. Here, again, it was necessary to cut open
the bulbs to detect this condition.
The performance of a certain percent of the bulbs of all
categories recorded here suggests that there is a considerable
difference in the time which may elapse between origin of a bud
on the basal plate between the bulb layers and visual evidence
of its presence by the bulb's splitting. The time required for this
to take place would vary, depending upon the growth, size and
location of the slab on the basal plate. A slab may be so tightly
enclosed in the bulb layers and outer sheath that there-is no
external evidence of its presence for two or more years. While
so enclosed it may, in turn, form an offset which, in some cases,
is freed the first year the slab is planted. This would account for
the splitting of a certain percent of the slabs recorded in the
experiment.
Griffith (5), referring to Papelr'it te and Chinese Sacred-lily,
states: "The number of splits is very large and they are inclined
Paperwhite Narcissus
to take place early". The data accumulated during these investi-
gations agree with this observation.
From the data presented it is strongly suggested that all
sizes of 10 centimeters and below be discarded. However, it is
fully recognized that growing conditions in the commercial
narcissus areas are apparently better suited to the growth of
the bulb and, for this reason, it is thought that a greater number
of marketable bulbs would be produced but the relative ratio
between the number produced by the different sizes would
remain approximately the same. Because of this, it is recom-
mended for commercial growers that all categories of bulbs 8
centimeters and below be discarded.
The results obtained clearly indicate that bulb size is one
of the most important factors affecting flower production. Seven-
ty-five and 83.3 percent of the 12 and 13 centimeter round bulbs,
respectively, used in these experiments, flowered. Statements
from growers in regard to this point indicate that a somewhat
higher flower production would be expected from the same size
bulbs grown in the commercial narcissus areas, but there is no
comparative data upon which to base this assumption.
It was found that the percent of the different grades of round
bulbs which flowered varied slightly from year to year, except
the 15 and 16 centimeter sizes. The same thing was also true for
mother bulbs and slabs except that the yearly variation extended
throughout the range of sizes.
SUMMARY
Data are presented which give information relative to the
growth cycle of Paperwhite narcissus. Slabs, round bulbs and
mother bulbs produced round bulbs and mother bulbs and the
percent of each category which did this varied with the size.
Size of original planting stock has a decided effect upon
the size and number of marketable bulbs produced as the larger
sizes yielded a greater number of salable bulbs over the duration
of the experiment. The desirability of discarding all categories
of 8 centimeters and below by commercial growers is suggested.
Experimental evidence presented shows that both bulb size
and category have a marked effect upon flower production.
The percent of bulbs flowering in each category varied directly
with the size, the larger sizes producing the most flowers. Bulb
category has a definite effect upon the ability of bulbs to bloom
and the greatest difference is between the slabs and mother and
round bulbs.
Florida Agricultural Experiment Station
LITERATURE CITED
/ 1. BIEKART, H. M. Iliilucinc of nitrogen on the splitting of bulbs of Paperwhite
narcissus. Ann. Rept. N. J. Agr. Exp. Sta.: p. 227. 1930.
i. BROWN, T. A. Flowering bulb culture in Florida. Univ. of Fla. Agr. Ext. Ser,
Bul. 48. 1928.
S3. EMSWELLER, S. L., G. O. RANDALL AND J. G. WEAVER. Fertilizer for narcissus
bulbs in North Carolina (progress report). Proc. Amer. Soc. Hort. Sci. 36:
791-795. 1938.
4. GRIFFITH, DAVID. The production of narcissus bulbs. U. S. D. A. Bul. 1270.
1924.
5. GRIFFITH, DAVID. Daffodils. U. S. D. A. Circ, 122. 1930.
v/6. GRIFFITH, DAVID. Speeding up flowering in the daffodil and the bulbous iris.
U. S. D. A. Circ. 367. 1936.
7. HAYWARD, WYNDHAM. Polyanthus narcissus in Florida. Year Book American
Amaryllis Society: 138-140. 1935.
8. LUMSDON, D. VICTOR. The influence of storage temperatures on the forcing of
King Alfred narcissus bulbs. Proc. Amer. Soc. Hort. Sci. 36: 786-790.
1938.
A9. PARKER, M. M. The effect of fertilizers on the yield of narcissus bulbs. Proc.
Amer. Soc. Hort. Sci. 33: 678-682. 1935.
S10. WHITEMAN, T. M. Effects of different storage temperatures on the forcing of
Paperwhite narcissus. Florists' Exch. 92, (19): 9, 12. 1939.
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