392 



AMERICAN BEE JOURNAL 



October 



plant. It is thought that the rm'pose 

 of these glands is to attract insects to 

 the flowers so that cross fertilization 

 may be effected. Both kinds of nec- 

 taries occur in the cotton plant. Ek- 

 tra-floral nectaries are found on the 

 mid ribs of the leaves. Theso glands 

 are diamond-shaped pits located about 

 one-sixth of the distance between the 

 stem and the top of the leaf. Other 

 nectaries, while very closely con- 

 nected with the flowers, are net true 

 flower nectaries. The flower is en- 

 closed in the ring or involucre of 



Fig. 1. — Flower of cotton, showing nectary on 

 side of calyx. 



three bracts and rarely a second ring 

 of bracts. At the base of each bract 

 is a large oval gland having an area 

 of about two square millimeters (fi.g. 

 No. 1). These glands are veiy con- 

 spicuous and often highly colored. 

 This group is popularly known as the 

 "eyes." Within the involucre, a true 

 tubular calyx encloses the flower. At 

 the base of this tube and at *hc open- 

 ings between the involucral bracts are 

 located three other nectaries fig. No. 

 2 ) . These are slightly smaller than 

 the first ring. A row of ne-taries is 

 located on the inside of the calyx at 

 the base of the petals. The petals are 

 so arranged that they overlap. These 

 nectaries are indicated by tufts of fine 

 plant hair, located near the base of 

 the petals. On account of the overlap 

 of the petals, the surplus nectar 

 from the calyx glands very often is 

 found within these clusters ot haii's. 

 This has given rise to the opinion that 

 the edges of the petals also have nec- 

 tar-bearing glands. In observing the 

 bees working upon the cotton blos- 

 soms for nectar, it appears that they 

 more often insert their tongues be- 

 tween the calyx and the petals to 

 reach this nectar than forc^' their 

 tongues between the petals. Thus it 

 appears that all of the nectar-liearing 

 glands of cotton are, in a way, extra- 

 floral nectaries. In no instance were 

 glands found at the base of the sta- 

 men column, which in most plants is 

 the location of the true flower nec- 

 taries. In several varieties of cotton, 

 however, purple areas exist at the 

 base of the petals. These areas are 

 similar in shape and location to 

 smaller areas called pathfinders, which 

 exist in other flowers and which indi- 

 cate the location of the nectary. From 

 the observation given It appears as 



if the nectaries were arranged to at- 

 tract the insects from and not into the 

 flower. 



Dr. Wm. Trelease, in "Nectar and 

 Some of Its Uses," in Comstock's re- 

 ports on insects, sug.uests that this 

 species of cotton has lost its true 

 floral nectaries since its domestication 

 and that, in its wild state, the many 

 extra-floral nectaries were of advan- 

 tage in attracting insoits to the plant, 

 and thus help in pollination. It is 

 learned that plants possessiig nec- 

 taries, when grown in soil having a 

 normal water content and a high per 

 cent of available plant food, will, dur- 

 ing periods when the surrounding air 

 has a high water content, secrete 

 more nectar than under any other 

 condition. As these limitations are 

 descriptive of the area in Texas 

 where cotton is a heavy nectar pro- 

 ducer, the above statement is ac- 

 cepted, not as stating the cause of, 

 but as giving the conditions governing 

 heavy secretion. 



One of the things greatly desired 

 by the student of floral ecology is 

 some means by which necta'- secre- 

 tion can be detected easily and meas- 

 ured accurately. In the cotton plant 

 the glands are so large they can be 

 easily measured. 

 Area of three glands on in- 

 volucre 6 sq. mm. 



Area of three glands on ca- 

 lyx 4.5 sq. mm. 



Area of three glands on 



petals 5 sq. mm. 



Total 15.5 sq. mm. 



A normal plant will aver- 

 age 5 blooms per day, 



6x15.5 77.5 sq. mm. 



Total area of gland on leaf 5 sq. mm. 

 A normal plant will average 

 100 leaves per day, 100 



X.5 127.5 sq. mm. 



During the blooming period, from 

 June 14 to October 15, (125 days) a 

 surface of (125x127.5) 15,937.5 sq. 

 mm. is exposed. As some plants do 

 not produce flowers or leaves on 

 which all the glands are present and 

 as rainy days prohibit working, this 

 area has been reduced to 100 sq. cen- 

 timeters. The secreting ai'ea of 100 

 square centimeters is about 15 square 

 inches, or a square about 4 inches on 

 a side. These glands have a total 

 depth of 3 millimeters. The surface 

 is not smooth, but is covered with 

 fine hair, so that it would require n 

 conr.iderable depth of accumulated 

 nectar before the liquid surface, such 

 .IS is often seen in nectaries would be 

 produced. It requires 5 grams of 

 nectar to produce a continuous layer 

 from a surface 10 centimeters square. 

 Thus a single cotton plant would have 

 on its surface, if the total secreting 

 surface were exposed at one time. 5 

 grams of nectar. Whether or not the 

 secretion is increased by part oi" it be- 

 ing removed by the bees is not known. 

 The weight of the raw nec'ar evap- 

 orated into honey of 12 lbs. standard 

 would be 2.5 grams. Thus the bees 

 will have to carry 2Vz gallons of nec- 

 tar to the hive to obtain one gallon 

 of honey. Analysis shows that fresh 

 nectar contains from 17.66 per cent 

 of solid matter, up to 82 per cent, 



which is the appro.ximate per cent of 

 the solid matter in old honey. This is 

 another and very important explana- 

 tion as to why some plants are much 

 better honey producers than others. 

 Bees working nectar containing 17.66 

 per cent would have to collect five 

 times as much material as when col- 

 lecting 82 per cent nectar, not to 

 mention the time employed in reduc- 

 ing it to the consistency of ripe 

 honey. A peculiar point that arises 

 here is the relationship between nec- 

 tar with a high water content, cane 

 sugar and fermentation. From analy- 

 sis at hand, all honeys from watery 

 nectar are high in per cent in cane 

 sugar, and even though they have 

 the same specific gravity as other 

 honeys, are apt to ferment. Cotton 

 nectar does not have a high water 

 content and is of medium thickness. 

 Thus bees will have to gather abo.it 

 twice as much nectar as the resulting 

 amount of honey. 



From the data presented above, the 

 honey from a single average plant 

 should be about one-half the weight 

 of the nectar, or 2 V2 grains. This 

 weight multiplied by 2,500, tlie aver- 

 age number of plants per acre, gives 

 6.25 kilos, or 13.7 pounds per acre. 

 While this is wild speculation, it is 

 based on sufficient facts to show why 

 the cotton plant is one of the fore- 

 most honey producers. It is further 

 believed, from observations, that the 

 secretion of nectar far exceeds that. 

 The amount of nectar in a certain 

 nectary did not seem to be reduced to 

 any great extent by the working of 

 bees upon it and it seems highly prob- 

 able that, up to a certain limit, the 

 more the bees work the cotton plant 

 the greater the secretion. Observa- 

 tion made by beekeepers liv'ng in the 

 cotton section would lead to the be- 

 lief that the average production of 



Fig. 2. — Nectaries under cotton square. From 

 these the honey is collected. 



honey to an acre of cotton '.■ about 

 28 pounds. 



While cotton blooms continuously 

 from the middle of June until frost, 

 and the nectaries secrete throughout 

 this time, it has two distinctive bloom- 

 ing periods during which large nectar 

 flows are noticeable. The first oc- 

 curs when the plant reaches a height 

 of about 2 feet and before the boll- 

 weevil commences to be destructive to 



