330 



MONOCOTYLEDONES. 



ever may be entirely wanting. The 3 posterior stamens are entirely 

 suppressed. The pollen is powdery. The ovary is 3-locular with 

 axile placenta. 7 species (Tropical East India, Australia). 



2. CYPRIPEDILEJ:. 1 The flower is strongly zygomorphic with a 

 large boat-shaped labellum. There are two perfect stamens be- 

 longing to the inner whorl, and the median anterior (later on the 

 posterior) stamen of the outer whorl is transformed into a large, 

 barren, shield-shaped body (Fig. 319). Selenipedilum has a 3-locular 

 ovary, but Cypripedilum (Ladies'-slipper) has a unilocular ovary 

 with 3 parietal placentae the typical structure for the Orchids. 



FIG. 319. Cijpripedilum calccolns : 1 front view of the flower ; 2 lateral view, after the 

 removal of all the perianth-leaves with the exception of the labellum, which has been 

 divided longitudinally ; 3 the slylar-column ; oo ovary ; s-s exterior, p interior perianth ; 

 p' the labellum ; a the two fertile stameus ; a' the staminode ; st the stigma ; i entrance for 

 the insects ; ex exit. 



The pollen-grains are separate (not in tetrads) and all the 3 lobes 

 of the stigma are constructed to receive them. This group is there- 

 fore, next to the Apostasieas, the least modified among the Orchids ; 

 in all the following groups, one of the lobes of the stigma is differ- 

 ently developed from the others, and there is only one stamen. 

 Terrestial Orchids The pollination of C. calceolus is effected by the 

 forcible entrance of insects into the boat-shaped labellum (Fig. 319 p') at /, aad 

 their escape at ex (in 2) where the anthers are situated ; in this way the 

 stigmas will first be touched and then the anthers. The pollen-grains are sur- 

 rounded by a sticky mass in order that they may adhere to the insects. 



1 Cypripedilum = Cypripe.dium. 



