COHESION AND StJPtEBSSlON. 



263 



of a l-merous corolla in an orchid mentioned under 

 tlie previous heading, due to fusion of two lateral 

 petals. A sketch was received from Mr. Gr. S. Saunders 

 of a flower of Gi/pripedinvi. SelUgerum whose perianth 

 consisted of a single anterior sepal and a single 

 posterior petal, this having the form and consistence 

 of a normal lateral petal (fig. 152). 



Fig. 152. — Cypripedium SelUgerum. Flower with monomerous 

 corolla. (G. S. Saunders.) s, sepal ; p, petal. 



Cases of suppression of the petals will next be 

 noticed. A flower of the orchid Calanthe vestita was 

 seen in which all three petals were absent. In a 

 flower of Selenipedium the labellum was the sole 

 representative of the corolla. In aKalmia all flowers 

 were entirely devoid of corolla, while the remaining 

 whorls were present in their normal condition. On 

 the other hand, the complete absence of the corolla in 



