SS ENGLISH BOTANY. 



ORDER XXXIII.— U MBELLIFER^J. 



Herbs, generally with hollow furrowed stems ; more rarely 

 undershrubs. Leaves alternate, very rarely opposite, frequently 

 ternately- or pinnately-compound or -decompound, without dis- 

 tinct stipules, but usually with the leaf-stalk dilated at the base, 

 especially in the uppermost leaves. Inflorescence usually a com- 

 pound umbel {umbel), with the primary rays bearing small simple 

 umbels (umbel! tiles), more rarely a simple umbel ; umbels usually 

 surrounded by whorls of small leaves (involucres) and umbellules 

 (involucels) by similar whorls. Mowers perfect or polygamous 

 (more rarely all unisexual), regular, or radiant by having the outer 

 petals of the exterior flowers larger, generally white, yellow, or 

 greenish. Calyx of 5 sepals, completely combined and adnate to 

 the ovary, with the limb reduced to a ring, more rarely 5-toothed. 

 Petals 5, frequently with the apex inflected so as to appear notched, 

 inserted round a fleshy disk which crowns the ovary. Stamens 5. 

 Ovary adherent to the calyx, crowned with a fleshy epigynous disk, 

 divided into 2 cushions (stylopods), 2-celled, each cell with a soli- 

 tary suspended ovule ; styles 2, distinct. Fruit (cremocarp) 2-celled, 

 generally separating when ripe into 2 achenia {inericarps), which 

 are most commonly suspended from a more or less deeply cleft or 

 entire columella, sometimes termed the carpophore. Each mericarp 

 has usually 5 ridges or ribs (primary ridges), and sometimes 4 

 intermediate ones (secondary ridges) ; generally there are also, in 

 the substance of the pericarp, small canals or tubes (vittce) con- 

 taining essential oil. Seed anatropous ; albumen copious, horny ; 

 embryo minute. 



Tribe I.— HYDROCOTYLE^. 



Elowers generally in simple umbels or heads, or in 2 or more 

 whorls one above the other. Petals entire, acute, valvate. Cremo- 

 carp laterally compressed, without calyx-teeth at the apex ; colu- 

 mella none ; inericarps convex or keeled on the back ; primary 

 ridges usually unequal, the intermediate ones often obsolete and 

 the lateral ones remote from the margin, the secondary ridges 

 none ; interstices without vittae. Seed flat or keeled on the inner 

 side. 



