ORD. I.] 21. TEESDALIA NUDICAULIS. 



40:i 



Diagnosis and Affinity. 



This plant has some resemblance to Draha vcnm, -which 

 blooms somewhat earlier however, and is much mt)re com- 

 mon. Both are of nearly similar stature, but Draha vema 

 is commonly the smaller ; its individual flower-stalks arc much 

 longer, the root leaves are undivided, and furnished with 

 three-pointed hairs. The petals are deeply indented, and the 

 fruit is a longish, pointed silicle, with many seeds. Lcp'uVium 

 nudicaulc L., which grows about Montpellier, and is figured 

 by Magnol (Bot. Monsp. p. 187.)? is also distinguished from 

 it, by the smaller lobes of its lyre-shaped root-leaves. But 

 De Candolle has shewn (Flor. Franc. 4. 708.), that this plant 

 is only a subspecies of ours. Thlaspi Bursa, also, has some- 

 times an appearance, which might lead us to take it for Tees- 

 dalia, since it has lyre-shaped root leaves, and white flowers. 

 But its stem is always branched and furnished with leaves : 

 the silicles, also, are inversely triangular, and contain many 

 seeds. Lepidium alp'mum and petraium L. have also some 

 resemblance to it ; but they have peculiarly pinnated leaves, 

 which grow on the stem, and lanceolate siliculae, furnished 

 with pointed extremities. 



This plant is commonly classed with Iberis, because its pe- 

 tals are somewhat unequal. But Iberis has the Valves of its 

 siliculae distinctly marginated, and has no appendages to the 

 filaments. These two circumstances constitute the diagnostic 

 character of the two genera. This plant cannot be classed 

 with Lepiduirn, because, in this latter gcnus^ the petals are 

 uniform, the filaments are without appendages, and the ra- 

 dicle of the embrvon is turned towards the ridge of the coty- 

 ledons. Thlaspi is still further distinguished by the winged 

 or marginated valves of the sUlcida, by the want of ap})end- 

 ages to the filaments, by having many seeds in its \(k\\\\, and 

 by the direction of the radicle towards the ridge of the coty- 

 ledons. 



Cc2 



