COHESION AND SUPPRESSION. 



249 



the same phenomenon occurs, as in the tendril of the 

 vine, which is an inflorescence modified to serve as a 

 climbing organ, and in which the tips of the pedicels 

 have become hypertrophied in order to serve as 

 adhesive disks. 



1. Sepals. — The phenomenon of synsepaly will first 

 be referred to. This may be partial or complete. 



In the pansy (Viola tricolor) incomplete fusion (the 

 double sepal being forked) was observed between the 

 two lateral anterior sepals ; this had a curious effect 

 on the petal opposite this double sepal : owing to lack 

 of space its spur was turned inside out, thus appearing 

 on the upper instead of on the lower side of the petal. 

 It is not infrequent in orchids, as in the late spider- 

 orchis (Ophri/s Arachnites) observed by Penzig, in 

 winch the two lateral sepals were fused together, the 

 single sepal so formed becoming opposite to the odd 

 sepal. In Gypripedium this same fusion is the normal 

 feature. Jaeger mentions a rare phenomenon in 

 Clematis Viticella, all the petaloid sepals being united 

 to form a campanulate structure, which was sometimes 

 distinctly two-lipped. 



Magnus observed in the orchid Trichopilia a 1-merous 

 calyx consisting of a posterior sepal, enclosing, on 

 the opposite side of the flower, a single petal which 

 was not labelliform ; hence this probably consisted of 

 the fusion of the two lateral petals, and if so the single 

 sepal probably arose from fusion of the lateral sepals, 

 accompanied by suppression of the " posterior " one 

 (PI. LI, fig. 9). 



Prillieux observed in Epictendrum Stamfordianum a 

 1-merous calyx of one posterior sepal, opposed to and 

 enclosing a single anterior petal which was a labellum ; 

 this being so, the two lateral petals were clearly sup- 

 pressed ; hence it is probable that the single sepal 

 represented the odd "posterior" sepal and that the 

 two lateral ones were suppressed. 



Stenzel describes a highly reduced flower of Orchis 

 globosa, in the axil of a bract a short way below the 



