49G Mackenzie: Onosmodium 



It will be noticed that under this characterization the plant 

 called Onosmodiiun Thurbcri by A. Gray (Syn. Fl, 2^ ; 205. 1878) 

 does not fall within this genus. That species, however, is so self- 

 evidently not congeneric with real Onosmodiiun that I feel no hesi- 

 tation in removing it therefrom. It differs from Onosmodium in 

 the greatly elongated corolla, exserted stamens, long filaments 

 and versatile anthers, in usually ripening more nutlets, and in the 

 persistence of the enlarged base of the style. For the present I 

 refer it to Macromcria as Macromeria Thurberi. It seems certainly 

 congeneric with M, viridiflora DC, M, cincrasccns DC, and JSL 

 discolor' Benth. Whether these species are congeneric with the 

 original species of Don I cannot determine at present, the material 

 I have seen being too scanty. 



Onosmodium strigosum G. Don, Gen, Syst. 4: 317 (1838), 

 and Onosmodi^im criocatdon A. DC in DC Prodr. 10 : 70 (1846), 

 both from Northern Mexico, may be the same. The former as 

 represented in herbaria is not an Onosmodi^tm^ the corolla and 



anthers both being very different. Of the latter I have seen no 

 specimens. 



The species of true Onosmodium which I have been able to 

 recognize may be distinguished as follows : 



Bracts ovate, rounded at base; fruiting pedicels usually exceeding the sepals ; corolla 



5-7 mm. long. 



I. O. Helleri. 



Bracts narrower, tapering at base ; fruiting pedicels rarely as long as the sepals ; corolla 

 9 mm. long or longer. 



Corolla-lobes narrowly lanceolate-acuminate, two to three times as long as wide. 

 Pubescence appressed. 2. O, virginianum. 



Pubescence spreading. O. virginianum 



hirsiitwn. 



Corolla-lobes broadly triangular-acute, little longer than wide, 

 Stem not glabrous below the branches. 



Nutlets noticeably pitted ; calyx-lobes 6 mm. long or less, noticeably 



soft-pubescent. 3. a moUe, 



Nutlets little if at all pitted ; calyx-lobes hispid. 

 Corolla-lobes merely acute. 



Nutlets strongly constricted at base. 



Nutlets less than 3 mm. long. 4. 0. hispidissimum. 

 Nutlets about 4 mm. long. O, hispidissimum 



macrospermum. 

 Nutlets not strongly constricted at base. 



Nutlets 4 mm, long (rarely a little less). 



5, 0, occidentale. 

 Nutlets 3 mm. long (rarely 3.5 ram. long). 



0. occidentale sylvesire. 



