D/^NDR^— CYPRIPEDIUM 41 



Sub-famHy DIANDRM Salisbury 



Fertile anthers two, stigmas thtee, confluent. 



DiANDR^ SaUsb., Prodr. stirp. hort. chap. vig. (1796). Cypripedie^ Lindley 

 (1826). Pleonandr^ Pfitzer (1903). 



Pleonandrs was probably adopted to cover the genus Nemviedia (Apostasiaces) which 

 has three fertUe anthers. The recognition of the latter as a separate family makes the 

 older name more accurate {vide "Evolution of genera and species", p. 11). 



Tribe I CvPRIPEDIEffi Lindley 



Fertile anthers two. Pollen-grains single, immersed in a viscid paste. Stigmas three, 

 united. 



Cypripedie^ Lindl., Orchid. sceleL i, 18 (1826). 



Genus I CYPRIPEDIUM L. 



Column cylindrical at base, then forking; upper branch a large stalked staminode; 

 lower branch 3-lobed, the mid-lobe expanding obliquely into a broad obtusely 

 triangular dry stigma, the side-lobes horn-like, each bearing an anther. PoUen-grains 

 single, immersed in a viscous paste within the anther. 



Perennial herbaceous erect plants, with short creeping rhizome, leaves inrolled in 

 bud, and large, usually sohtary, flowers. Lateral sepals united lengthwise beliind the 

 lip. Petals long, spreading. Lip inflated into a large bag or pouch, spurless. 



About 30 species inhabit northern temperate regions (of which C. passerinum 

 Richardson extends north to Hudson Bay and the Yukon, and one species to Mexico). 



Sticky pollen is rather uncommon in other families of plants, being apparently 

 found only in certain genera of Onagraceas, e.g. Yuchsia, Epilobium, CEnothera, and 

 in the genus Rhododendron (including A^akd). In these plants the grains are held 

 together either singly or in fours (tetrads) by means of slender sticky threads, the 

 whole being adhesive, but not to the extent that obtains in the Diandr^. In Asclepia- 

 daceas the pollen is massed together in pollinia as in the Monandry, but these pollinia 

 are not themselves sticky. Stigmas with papillas on the surface are fairly general 

 throughout flowering plants, and such papillae usually indicate the precise extent of 

 the stigmatic surface, particularly where style and stigma are not otherwise easily 

 separable. The papillae, however, are not usually sharp-pointed, but rather blunt. 

 Sticky stigmas, as found in the Monandras, are, on the other hand, relatively rare 

 among other families of plants. 



