﻿Arthur: New species of Uredineae 589 



been studied in a species of this character, in which the sowing of 

 aeciospores produces teHa directly without the intervention of 

 uredinia. It is probable that this is the first time that such 

 spores have been seen to germinate. It is not known whether 

 or not they are capable of infecting a plant and reproducing the 



Puccinia nodosa Ellis & Harkn., a species found on Diptero- 

 stemon capitatus (Benth.) Rydb. {Brodiaea capitata Benth.) from 

 San Francisco to the southern part of California, differs from the 

 one here proposed by having a definite uredinial stage with 

 prominent sori. The hosts of the two species are similar, differing 

 most strongly in the abundance of flowers in the umbels. D. 

 capitatus is a Californian species, while D. pauciflorus ranges 

 through southern Arizona into the border of New Mexico. 

 Puccinia nodosa has not yet been cultured. 



It was through the kindness and generous assistance of the 

 director of the Desert Laboratory and of his staff of workers that 

 the discovery of this rust and the brief but highly significant studies 

 of it were made possible, and it is to acknowledge in part this aid 

 to science that the first word in the title of the institution has been 

 chosen for the specific name of the new species. 



O. Pycnia hypophyllous in small groups surrounded by the 

 telia, subepidermal, globoid as seen in section, 130-190 n in diam- 

 eter ; ostiolar filaments 30-40 n long. 



III. Telia hypophyllous, closely placed in elHptical groups 

 3-10 mm. long surrounding the pycnia, elHptical, 1-2 mm. long, 

 becoming naked by longitudinal rupture of the epidermis, pulveru- 

 lent, blackish; teliospores broadly ellipsoid, 32-42 by 48-61 ;u, 

 slightly or not constricted at septum, rounded at both ends; wall 

 dark chestnut- to blackish-brown, uniformly 3-5 m thick, coarsely 

 and prominently tuberculate; pedicel colorless, fragile, appearing 



On Dipterostemon pauciflorus (Torr.) Rydb. {Brodiaea capitata 

 pauciflora Torr.), Tumamoc Hill, grounds of the Desert Botanical 

 Laboratory, Tucson, Arizona, altitude 2,700 feet, February 26, 

 1914, /. C. Arthur & F. D. Fromme 5801a. This is the short- 

 cycle form corresponding to the long-cycle species, P. Carnegiana 



