198 



NATURAL HISTORY OF PLANTS. 



cumbent or more rarely accumbent 1 on the cotyledons. The fruit is 

 indehiscent, or opens late by a vertical cleft separating the two car- 



Myagrum perfoliatum. 



\y 



Soholetrskia 

 lithophila. 



pellary leaves. The genus Woad comprises annual or biennial herbs, 

 with erect branching stems, and entire or subentire leaves, the cauline 

 often sagittate. The flowers 2 form ramified ebrac- 

 teate recemes. The fruits are borne on drooping 

 pedicels. Some thirty species of this genus are known, 3 

 natives of Europe, Asia, and North Africa. 



The Woads have been made of late years the 

 type of a series, Isatidea, somewhat artificial, like 

 most that have been made in this order, and containing 

 twenty-four other genera. These have a usually short 4 

 fruit or indehiscent silicule, not articulated, often 

 subdrupaceous before complete maturity, and then 

 crustaceous or bony, winged or wingless, usually one-celled and one- 

 seeded. Sometimes there are two seeds, or several one-seeded 



Fig. 267. 



lower, perianth 

 removed. 



chambers. 



The characters of the seeds are of slight essential im- 



Sel, ii. t. 77;— Jaub.& Space:, III. PI. Or., Hi. 

 t. 225), hence held the type of a distinct genus. 



1 Especially in Chartoloma (Bge., in Hot. 

 Zeit., ii. 249; JEwum, PI. Leltn., 23, t. 3; — 

 "VValp., Sep., v. 49; Ann., iii. 823), which has 

 also been made a distinct genus. 



3 Usually yellow. 



3 Reichb., Ic. Fl. Germ., ii. t. 4.— Deeess., 

 Ic Sel., ii. t. 77-79.— Bois?., Fl. Or., i. 374 

 {Sameraria), 376.— Geex. & Godr., Fl. de Fr., 

 i. 138.— Walp., Sep., i. 180; ii. 762; v. 44; 

 Ann., i. 46; ii. 52. 



4 The only exceptions are in certain species of 

 Sololeicskia and Spirorhynehus. 



