348 PROCEEDINGS OF THE AMERICAN ACADEMY. 



Geraea in the section Euencelia, and Barrattia in Simsia. Since Dr. 

 Gray's treatment nothing has been done in the way of a revision of 

 the group as a whole, nor has any new species been described under 

 any of the genera Pallasla, Armania, Geraea, Barrattia, or Simsia 

 since 1859. 



In 1871 D. C. Eaton ^^ described as Tithonia argophylla a remarkable 

 new species from Utah, with large solitary heads, squamellaceous 

 corona between the awns of the achene, and densely silvery -pubescent 

 basal leaves, which two years later was referred to Encelia by Dr. 

 Gray,^^ who at the same time added a very similar new species (E. 

 nudicavlis). Ten years after Gray ^° transferred them to Helianthella, 

 instituting for their reception the new section Enceliopsis. In 1909 

 x\\'en Nelson ^^ ele^'ated the group to generic rank, mainly on the basis 

 of habit, enumerating fi\'e species, one of them new, which I have not 

 been able to separate from E. nudicaidis. 



Hemsley ^^ in 1881 listed 17 species of Encelia from Mexico, de- 

 scribing one new species and making many new combinations of names 

 which had been first published under Simsia. 



In recent years the boundaries of the genus Encelia ha\e been 

 stretched to include a number of shrubby Mexican species, usually 

 described from material without ripe fruit, which in the light of all 

 their characters require transferral to other genera {Vicjuiera, Flouren- 

 sia, Verhesina) if generic distinctions in this group are to be preserved. 

 Six species {E. hypargyrea, maculata, montana, Pringlei, rhomhifolia, 

 squarrosa), with achenes plumpish when mature, so far as known, and 

 a persistent pappus of two aristate or paleaceous awns and several 

 short truncate squamellae, exactly agree with Viguiera in essential 

 characters and are further on transferred to that genus. Another 

 fascicle of six species {E. coUodes, glutinosa, micropkylla, oblonga, 

 rcsinosa, suffrutescens) is not so easily placed owing to lack of ripe 

 fruit in nearly every species, but all differ in more or less essential 

 characters from the true genus Encelia, and may by a slight extension 

 of character be inclufled in Flourensia DC.^^ This genus, wrongly 

 referred by Bentham ^^ to Ilelianthus, was based on four species, two 

 radiate Chilean plants and two discoid Mexican species, the latter 

 taken by Gray ^^ as typical of the genus. One of the Chilean species, 



18 In Wats. Bot. King's Rep. v. 423 (1871). 



19 Proc. Am. Acad. viii. 657 (1873). 23 Prod. v. .592 (1836). 



20 Proc. Am. Acad. xix. 9 (1883). 24 Gen. PI. ii. 376 (1873). 



21 Bot. Gaz. xlvii. 432 (1909). 25 Proc. Am. Acad. xix. 7 (1883). 



22 Biol. Centr.-Am. Bot. ii. 183-5 (1881). 



