1888 



GLEANINGS IN BEE CULTURE. 



477 



have been visiting:, by simply dissecting: their 

 stomachs. The sculpture, or external markings of 

 pollen grains, are quite as varied as their g'eneral 

 forms. Some are smooth, others rough; some are 

 ridged, others grooved; some are pitted, while 

 others bristle with sharp points (Fig. 1). Of ten, as 

 seen in the figure, these projections vary in the 

 same pollen grain. 



The pollen grains are developed in the anthers, 

 or ends of the stamens of the flowers. In order to 

 fructify the ovules, these grains must lodge on the 

 soft stigma, or end of the pistil. But frequently 

 the stamens and pistils are in different plants. In 

 other cases, where stamen and pistil are in the same 

 blossom, " Nature shows her abhorrence of close 

 fertilization " by causing the stamens and pistils of 

 a flower to mature at different times. Hence the 

 great necessity of bees and other insects for the 

 performance of this important work in vegetable 

 economy. They must carry the pollen to the stig- 

 ma. Where any such union is so important, and 

 yet in the nature of things accidental. Nature is 

 always very lavish. Thus the female tish simply 

 drops her eggs, or roe, in the water. The milt from 

 the male passes into the same medium. Here the 

 union must be accidental, and dei)ends on favoring 

 currents; hence the eggs and sperm-cells of fish are 

 numbered by millions. For alike reason the pollen 

 grains of plants are exceedingly abundant, and far 

 outnumber the seeds. Thu& in the Chinese wis- 

 taria, a beautiful climbing bee-plant, illustrated in 

 my Manual, there arc, says Goodale, seven thou- 

 sand grains of pollen to about thirty ovules. Has- 

 sall estimates that the number of grains in a single 

 plant of rhododendron is seventy-two million six 

 hundred and twenty thousand. 



Each pollen grain is a single cell, having two 

 coats— an outer, extine, and an inner, intine, for its 

 wall. It is the extine which is beset with projec- 

 tions, in rough pollen grains. The extine is also 

 frequently perforated, as seen in the figure. In 

 this case the intine linos these holes, or openings. 



As previously shown in an article in Gleanings, 

 the contents of each pollen grain is protoplasmic 

 matter. This is rich in albuminous material. In- 

 deed, the chemical composition of pollen is not 

 greatly unlike that of some of our grains, as oats, 

 barley, etc. 



When the pollen grain lodges upon the stigma, if 

 the latter be in a right condition, as shown by its 

 adhesive secretion, the pollen grain increases some- 

 what in size, and soon a tube, sometimes more than 

 one, pushes out through a perforation of the ex- 

 tine. This tube passes through the whole length of 

 the style till it reaches the ovule which is to be 

 fertilized. The time required for the descent of the 

 pollen-tube varies from a few hours to two or three 

 days. A. J. Cook. 



Agricultural College, Mich. 



Tlianks, friend Cook ; but as you do not 

 tell us very much about this wonderful en- 

 graving, which we reproduce from an article 

 m the Bienen Zeitung of September last, we 

 have taken the following (lescription from 

 the author, Parson Schonfeld. It is no 

 more than fair to say, however, that our ad- 

 mirable translation was made by Mr. Cow- 

 an, of the British Bee Journal. 



The percentage of nitrogenous matter which 

 these excreta contain is very high, seeing that they 

 are largely mixed with broken pollen grains, as 



mentioned above. The exterior membrane of pol- 

 len, called the exine, is known to possess a great re- 

 sisting force. Besides, the stomach of the bee, 

 much less the stomach of the larvie, is unable to 

 make all jiollen grains discharge their contents of 

 protoplasm. For the discharge of the protoplasm 

 in the natural way takes place, in most cases, not 

 by the c.xine simply bursting, but through special 

 valves in the exine, which remain closed as long as 

 the pollen is kept dry. In ray last article I gave a 

 sketch of an unliroken pollen grain from a pump- 

 kin blossom to which I have to direct attention 

 once more. It shows the lids of the valves. When 

 the pollen grain is moistened, the protoplasm 



FIG. 1. 



swells and raises the valves, as shown in the 

 figure at a until at last the lids fly back, and 

 the protoplasm discharges itself at h. But this 

 mechanism often fails to act in the stomach 

 of the bee, and the pollen then remains closed, and 

 is of no use to the bee. This is proved by the large 

 number of whole pollen grains frequently found in 

 the rectum of bees. 



The above is very well so far as it goes ; 

 but neither our good friend Parson Schon- 

 feld nor Prof. Cook has told us as much as 

 a natural-born Yankee like myself would 

 like to know about this wonderful picture. 

 Those pot-lids with a sharp spike on, sug- 

 gest to me the safety-valve of a steam- 

 boiler ; and at b we have something very 

 much like the escaping steam. 1 suppose 

 we are to understand that this is proto- 

 plasm. Well, if every pollen grain from a 

 pumpkin-blossom is like this one, and na- 

 ture produces them by the million, wh;it an 

 awful big lot of work nature has to do ! We 

 sometimes hear people talk about cheap la- 

 bor ; but who can contemplate the amount 

 of labor that is performed in constructing 

 even a single one of these strange pollen 

 grains? Now, are we to understand that that 

 whole big sphere is full of protoplasm, and 

 tliat, when one of those lids flies oft', tlie 

 whole contents boils out like yeast out of a 

 jug when the cork is forced out by pressure? 

 If this is so, I presume that every time we 

 eat bee-bread we swallow millions of these 

 wonderful pollen-cells ; and this protoplasm 

 is probably nutritious to human beings as 

 well as to bees, providing it gets uncorked 

 so it can come out. But where it is not 

 gathered by the bees, but falls on to the 

 stigma, it then bursts open, when it gets 

 sufficiently ripened, and this aforesaid proto- 

 l)lasm plays some important part in produc- 

 ing the seed of the plant. Who has not, 

 some time in childhood, stood with open 

 mouth and contemplated the wonderful phe- 

 nomenon of life, bursting up within the 



