ROBINSON.— DIAGNOSES ETC. OF SPERMATOI'HYTES. 517 



1.2 cm. longis ca. 2 mm. latis obtusiusculis; achaeniis 7.3 mm. 

 longis subfusiformi-columnaribus griseis glanduloso-hispidulis ; pappi 

 setis laete albis 1.2 cm. longis tenuissimis levissime scabratis numero- 

 sis. — Limestone ledges, Iguala Canon, near Iguala, Guerrero, Mexico, 

 altitude 760 m., 28 December, 1906, C. G. Pringle, no. 13, 921 (type, 

 in Gray Herb.). The broadly winged stems would seem to place this 

 species near T. pferocaulis Robinson & Greenman and T. alata Don. 

 The former, however, has the bractlets of the outer involucre shorter 

 than the scales of the inner involucre, leaves subentire, etc., while in 

 T. alata Don the bractlets of the outer involucre are ovate-lanceolate 

 and acuminate. The long obscure T. michuacana LaLav. & Lex., 

 which from the original description would appear to have some points 

 in common and might well be found in the same region, is said to have a 

 simple herbaceous stem and a thyrsiform inflorescence nearly a foot 

 long. 



Launaea picridioides (Webb.), 1. c, comb. nov. Rhabdothcca 

 picridioides Webb, in Hook. Nig. Fl. 146 (1849). 



