Rydberg : Rocky Mountain flora 431 



StrcptnntJius wyoiinngciisis A. Nelson but probably rather a TJicly- 

 podiinnr This note made the writer compare the latter species. 

 When S. %vyonii)igcnsis was first described, it was thought that it 

 was the closest relative of 5". iiiaciilatits Nutt., the only original 

 Streptanthiis, but a closer comparison now has shown that the pod 

 is not flat as in Streptantluis and the lobes of the stigma are turned 

 the wrong way. Its relationship is with the three TJiclypodia just 

 mentioned above, with which it also agrees in habit. 



Two other species of Thclypodiiim are said by Dr. Robinson 

 to have the lobes of the stigma placed in the same way, viz. : T. 

 vncraiitJiuui and T. hnigifoliiiiii, but here that character is scarcely 

 noticeable. There are other characters in which they disagree 

 with the other TJiclypodia. The branched or stellate pubescence 

 is unique in the whole tribe and should place them according to 

 the classification used in Engier & Prantl's Pflanzenfamilien in 

 another grand division of the family. The stamens and the pods 

 are, however, more or less thelypodioid. In both species the 

 flowers are more or less irregular, the lower sepals being longer 

 (this is best shown in T. lougifolhiiii) and there is scarcely any 

 distinction between claw and blade in the petals. 



The most interesting of the TJiclypodia is perhaps T. Wrightii. 

 In the pod, the texture of sepals and petals, the form of the latter, 

 etc., this is close to the typical TJiclypodia. The habit is not so 

 essentially different either, but the sepals are spreading-reflexed 

 and early deciduous as in Staiilcya and the glands at the base of 

 the stamens and the thickening of the pedicel, both so conspicu- 

 ous in most thelypodioid plants, are here inconspicuous. The 

 plant could not be included in Stanlcya, on account of the short 

 stipe, the different habit and the structure of the petals. 



The genera may be distinguished as follows : 



Sepals equal or nearly so ; hairs simple or none. 

 Sepals erect or ascending in anthesis. 



Stigma distinctly lobed, its lobes expanded over the septum. 



Thelypodiopsis. 

 Stigma entire or, if indistinctly lobed, the lobes expanded over the valves. 

 Stigma truncate ; sepals scarcely gibbous at the base. 



Septum of the pod without a distinct midrib. Thelypodium. 



Septum of the pod with a strong midrib. Pleu7-ophragt)ia. 



Stigma conical ; the outer sepals gibbous at the base. Hesperidatithus. 

 Sepals strongly spreading or reflexed in anthesis, soon deciduous. 



Stanleyella. 



