ULMAOE^. 187 



GENERA. 



I. ULME^. 



1. Ulmus T. — Plowers hermaphrodite or more rarely polygamous; 

 receptacle short generally rather concaTe. Calyx marcescent, 5-8- 

 lobed, imbricate. Stamens equal in number and opposite to lobes ; 

 filaments inserted more or less deeply in the cupule of the recep- 

 tacle (hence slightly perigynous) free exserted ; anthers in aestiva- 

 tion erect extrorse ; cells 2, longitudinally rimose. Germen (some- 

 times in male flower effete) 2-carpellar, 3-looular; the second cell 

 abortive effete (or more rarely fertile) ; style short, 2-fid at apex ; 

 lobes densely papillose-stigmatose witbin. Ovules descending 

 anatropous ; micropyle extrorsely superior. Fruit samaroid, clothed 

 at base with cupule of receptacle and often stipitate, surrounded by a 

 marginal wing entire or more or less ciliate ; cell eccentric com- 

 pressed reticulately veined, sometimes longitudinally nerved, l-sper- 

 mous. Seed descending ; coat membranous, 2-plicate ; cotyledons of 

 exalbuminous embryo plane or plano-convex rather fleshy ; radicle 

 superior straight. — Trees or shrubs, not milky ; branches sometimes 

 suberose ; leaves alternate, 2-stichous,, serrate penninerved, unequal 

 at base ; stipules lateral free ; flowers early or rarely late, breaking 

 from perulate buds, collected in loose shortly stipitate compound 

 cymes ; pedicels articulate, bracteolate. {Temp, and sub-frigid 

 regions of the north, hemisphere of loth worlds.) See p. 140. 



3? Holoptelea Pl.i — Flowers (nearly of Ulmus) polygamo- 

 moncecious, 4-8-merous ; stamens rarely free from sepals equal in 



I Ann. So. Nat., ser. 3, x. (184S). 259 ; DC. Frodr. xvii. 163. 



