Rydberg: Studies ox the Rocky Mountain flora 317 



Ammodenia oblongifolia (T. & G.) Rydl). comb. nov. 

 Arcnaria pepJoidcs major Hook. Fl. Bor.-Am. i: 102. ^831. 

 Ilonckenya oblongifolia T. & G. Fl. N. Am. i: 176. 1838. 

 Arcnaria sitchcnsis Dietr. Syii. PI. 2: 1565. 1840. 



B. T. Butler has collected in Montana what seems toheAre- 

 naria laricifolia L. At least it is the same plant as the one col- 

 lected by Turner on the Porcupine River, Alaska, on the strength 

 of which A . laricifolia is included in the American flora. 



Sagina occidcntalis S. Wats, has been collected in Idaho by 

 Lei berg. 



CARYOPHYLLACEAE 



Wahlber(;ella Fries, Bot. Not. 1843: 143. 1843 

 The treatment of the Silenoid genera of this family has been 

 very different in this country and in Europe. S. Watson and 

 B. L. Robinson admitted only two genera, Silenc and Lychnis, 

 while Pax* admitted beside Silene the genera Lychnis, Melan- 

 dryuni, and Viscaria, and Williamsf admitted Lychnis, Coronaria, 

 Viscaria, Eudianthe, and Melandrium. The only distinction given 

 by Watson and Robinson is the number of styles, in Silene 3, 

 in Lychnis 5, but Robinson admits that in some species of Silene 

 the styles are sometimes 4 or 5. The number of styles is therefore 

 not a very relial)le character. Continental authors usually dif- 

 ferentiate Silene from Melandrium (by Americans included in 

 Lychnis) by the partially septate capsule of the former. According 

 to Robinson this character is unreliable in our American species. 

 Perhaps the species included in Silene without septum should be 

 removed to Melandrium or to Eudianthe. As these doubtful 

 species are not found in the Rockies, I shall give no opinion on them 

 here. It is e\'ident that the genus Lychnis as treated in America 

 is an unnatural and composite group. Williams' treatment is 

 perhaps the most logical. Pax included our native American 

 species of Lychnis in Melandrium but divided the genus in three 

 subgenera. One of these subgenera corresponds to Eudianthe 

 with only 3 styles. The other two subgenera corresiwnd to the 

 original species of Melandrium and the genus Wahlbergella of Fries, 



* Engl. & Prantl, Nat. Pflanzenf. 3: ib: 70, 73- 1889. 

 t Jour. Bot. 31: 170, 171- 1893. 



