215 



to Novemi)er 8. V.)0-i. nt Miik-li l:i;<t date I'oiTy-seveii yerfeut tloweis were 

 counted. Long l)etore November heavy I'rost had ended all insect visits 

 and the plant had been dependent on self-pollination for fertiliasition for 

 a mouth. With fiost came some noticeable changes in the mechanism 

 of the flower. The end of the style was not so uniformly bent upward, 

 and the pollen-bearing hairs were much more persistent. During the 

 latter period self-fertilization was effected by the lobes of the stigma 

 beuding back until the papillose extremities touched the pollinated hairs. 

 The same movement may have occurred earlier in the season, but if it 

 did it was not so ol:)vious, and many times it would have beeu useless, as 

 the styles were denuded of their hairy appendages, and the lobes not 

 yet reflected more than usual. 



"Within the inflated limb of Pfiitsfoiiuii Peiit.stniioii (Li Britton the tila- 

 nients are free, and clustered with the style under the upper lip. One 

 pair of the didynamous filaments is nearly free from the corolla tube, 

 while the other pair and the sterile filament are imbedded in the wall 

 of the tube below the infiation. The bases of the free filaments are 

 dilated, with a concavity on the inner faces in Avhich honey is secreted. 



As a result of this arrangement the throat of the corolla is so ob- 

 strticted l)y the two free filaments and the style as to prevent anj- insect 

 from reaching the honey glands, without some special adaptation to over- 

 come the obstruction. To secure liouey the visiting insects must be armed 

 with a stout pair of Jaws to force an opening between the filaments and 

 style and with a tongue 14 mm. long. These necessary equipments are 

 found in AnthopJtora abnipta Say, a small bumble-bee. For two seasons 

 this bee has been the only insect seen to enter the corolla of a large, 

 cultivated plant, under daily observation while in bloom. Anthophorse 

 never missed putting in an appearance during some part of the day, if 

 the weather was fair, and sometimes as many as half a dozen were seen 

 on the plant at the same time. 



Anthophone ubnipUr never were seen collecting pollen, but as they 

 forced their bodies into the inflated portion of the flower they were well 

 dusted with it on their hairy backs. This pollen was carried to the next 

 stigma under which they passed, where some of it was left, provided 

 the stigma was ready to receive it. Usually the stigmatic end of the 

 style is pressed against the upper lip of the corolla during the first day 

 of anthesis. after that period it is bent dmvnward and is cross-fertilized 



