1893.] NATURAL SCIENCES OF PHILADELPHIA. 305 



The lobes of the corolla expand soon after daylight, resting at 

 once when open. But the style continues to lengthen. The appen- 

 dages to the stamens, similar in form to the lobes of the corolla, 

 bend over, and completely cover the apex of the style, forming a 

 cap like the apex of the finger of a glove. Pressing against this 

 cap the whole column is carried upward by the style growth. At 

 length the filaments will stretch no more — the style still advances 

 — the pollen is brushed upward by the plumose stigmas, and at 

 length the appendages of the anthers are forced apart, and through 

 the crevices the pollen is thrust. Pollen gathering insects have a 

 rich field throughout the day, collecting the material thus forced to 

 the top of the staminal tube. By sunset the stigmas appear, cov- 

 ered by pollen ; and it is interesting to note, by examination of a 

 floret at this stage, how nearly clean the pollen has been brushed 

 out b" the upward movement of the style. At sunset the pollen- 

 covered style commences to expand, and, curving over, seems to aid 

 in pressing back the column of stamens to the interior of the floret. 

 It was clear to my mind that the withdrawal of the staminal column 

 was not wholly due to elasticity of the filaments or it would go down 

 rapidly on the egress of the style which had raised it. But to make 

 the matter more certain, I slit the column, so that it might be entirely 

 free of any help from the style, but this did not add to the descent. 

 The filaments are as long as the tube when the latter has attained 

 its greatest elevation ; but when examined in the morning after the 

 above observation, when wholly withdrawn into the tube of the 

 floret, they had drawn down to but one-fourth the length. The 

 lowering is due, not to irritability nor to elasticity, but the 

 shrinkage common to all maturing structures. 



Pollen grains were of course more numerous on the dorsal side of 

 the style branches, but there was abundance for all fertilizing pur- 

 poses on the stigmatic surfaces. At any rate, as the expansion com- 

 mences at sunset and continues throughout the night, any fertil- 

 ization which insects might aid would be due to nocturnal insects 

 and not honey bees or others which have hitherto received the credit, 

 simply because they were pollen gatherers from the unopened 

 florets. 



The morning following the expansion of the style branches, the 

 style itself follows the stamens, and by nightfall of the second day 

 the style has wholly withdrawn into the corolla. During this day 

 the flower is visited by bees and other insects for nectar, but the 



