42 PROCEEDINGS OF THE AMERICAN ACADEMY. 



acuta vel obtusiuscula vel brevissime acuminata basi cuneato-attenaata ; 

 capitibus laxe corymbosis longe pedicellatis radiatis, disco leviter con- 

 vexo ; involucri squamis paucis subaequalibus ovatis vel late oblongis 

 acutis herbaceis hirsutulis ca. 7 mm. longis ; flosculis disci numerosis, 

 corollis anguste tubulosis aurantiacis 7 mm. longis externe glabris, 

 tubo proprio brevi basi ampliato ; faucibus multo longioribus paulo et 

 gradatim amplioribus 5-nerviis, limbi dentibus 5 brevibus ovato-lanceo- 

 latis acutiusculis apice puberulis ; achaeniis turbinato-cylindricis 2.8 

 mm. longis sericeis, pappi setis plumosis numerosis attenuatis plus 

 minusve inaequalibus ca. 2.6 mm. longis ; flosculis radiatis 5, ligulis 

 albis late oblongis vel suborbicularibus patentibus apice 3-dentatis 

 6-10 mm. longis. — River ledges, Balsas Station, alt. 600 m., 27 Sep- 

 tember, 1905, Guerrero, Mexico, C. G. Pringle, no. 10,075 (type, in hb. 

 Gray). This species is habitally similar to T. tenuifoUa Rose, which, 

 however, has smaller leaves and pappus decidedly longer than the 

 achenes. 



Galinsoga filiformis Hemsl., var. epapposa Robinson, n. var., 

 habitu foliis inflorescentia, etc., formae typicae simillima ; achaeniis 

 omnino epapposis apice annulo albido inconspicuo coronatis ; foliis caul- 

 inis quam eis formae typicae paululo minoribus. — San Ram6n, Du- 

 rango, Mexico, 21 April- 18 May, 1906, Dr. E. Palmer, no. 127 (type, 

 in hb. Gray). This puzzling plant, which according to the notes of the 

 collector was found in numbers, much dried, on stony ridges among 

 trees and bushes, differs in its lack of pappus from any other Galinsoga. 

 Its otherwise close correspondence with G. filiformis, however, would 

 seem to show that it is merely a new instance of a calvous form of an 

 ordinarily pappus-bearing species. Similar cases are familiar in sev- 

 eral neighboring genera, e. g. Calea, Jaegeria, etc. The phenomenon 

 seems to present an ecological problem of interest, and it is to be hoped 

 that collectors who have an opportunity to study these plants in the 

 field may bear the matter in mind and endeavor to learn the conditions 

 which determine the presence and absence of pappus in these in other 

 respects essentially identical forms. 



Flaveria bidentis Robinson, n. comb. Ethulia hidentis L. Mant. i. 

 110 (1767). Flaveria chilensis Gmel. Syst. 1269 (1796); Johnston, 

 Proc. Am. Acad, xxxix. 285 (1903). Milhria Contrayerba Cav. Ic. PI. 

 i. 2, t. 4 (1791). The author has examined the type of Ethulia bidentis 

 in the Linnaean Herbarium and finds that, as given in the Index Kew- 

 ensis, it is the plant which has long passed as Flaveria Contrayerba. 

 The Vienna rules of nomenclature require the restoration of the earlier 

 specific name. 



Pericome macrocephala Robinson, n. sp., griseo-pulverula vel 



