I 



FERTILIZATION IN CYPRIPEDIUM 



CONTRIBUTIONS FROM THE HXTLL BOTANICAL LABORATORY 103 



LuLA Pace 



(with plates xxiv-xxvii and one figure) 



The orchids have attracted much attention on account of their 

 striking habits and especially because of their remarkable adapta- 

 tions to insect pollination^ but the record of morphological investiga- 

 tion is a very scanty one. Morphologists have doubtless regarded 

 them as highly specialized forms, whose interest probably lies within 

 themselves rather than in any connection with the larger problems 

 at present attracting attention. In the stages of development extend- 

 ing from the archesporium of the ovule to fertihzation, Strasburger's 

 account (43) of Orchis pallens, in 1878, indicated that the familiar 

 angiosperm stages were present in the family. Later, the same 

 investigator (44) states that no parietal cell is cut off in Gymnadenia 

 conopsea; and Goebel (22) makes a similar statement for Orchis 

 pallens, probably based upon Strasburger's original account of 

 this species; but Dum:^e and Malinvaud (19) report several genera 

 with parietal cells. Recently Nawaschin (35) and Strasburger 

 (45) have discussed triple fusion in the orchids and its relation to 

 endosperm development, the former claiming that in tropical forms 

 the nuclei remain in contact but do not fuse, the latter stating that 

 fusion occurs in the forms he had investigated. In connection with 

 the development of the embryo, especially in reference to certain 

 remarkable suspensors of the group, there is a considerable body of 

 literature, but it Hes beyond the scope of this paper. 

 • The greater part of the material for the present investigation was 

 collected in the vicinity of Chicago in the summer of 1906, small 

 collections having been made also in 1896 and 1898. The collections 

 of 1906 were made June 17, July 4, ii, 17, and 27, Cypripcdium 

 spectabile and C- parvifforum furnished the greater part of the mate- 

 rial, but C. pubescens and C. candidum v/ere examined also in a 

 few stages. The youngest material collected was from flowers just 



353] 



[Botanical Gazette, vol- 44 



