38 ARTHUR: NEW SPECIES OF UREDINEAE 
four genera, in accordance with his well-known scheme of classifica- 
tion of the Uredinales in general. 
There is justification in separating these forms into four species 
aside from their cyclic behavior, for each has small morphological 
features that show distinctive structural advance in addition to 
physiological habit. The aeciospores of L. tucsonensis are slightly 
smaller and thinner walled than in the other species, and the telia | 
are large and at first blister-like, tending strongly to coalesce, 
instead of small and evenly scattered as in P. fusca and T. punctata, 
or somewhat circinating as in T. cohaesa, and have more mesospores 
than any one of these. 
The vicinity of Tucson seems to be especially favorable for the 
appearance of the less usual cyclic development of various forms 
of rusts. It was within a few hundred yards of the Desert Botan- 
ical Laboratory that Puccinia Carnegiana and P. tumamocensis, 
the long and short cycle forms of a divergent rust on Dipterostemon 
(Brodiaea) were found and somewhat studied. The new rust on 
the upright euphorbias, recently discovered by Mr: E. Bethel, 
and described in this article, is evidently a product of similar 
environmental conditions. In fact the whole arid region of 
southern Arizona and California offer a remarkable field for the 
study of the cyclic development of the rusts. Not only the cyclic 
development but also the cytological features of the rusts, espe- 
cially those displaying contracted cycles, greatly need investiga- 
tion, and in no species more than in the one under discussion. 
TELEUTOSPORA Arthur & Bisby, gen. nov. 
In his paper on the short cycle Uromyces of the United States 
G. R. Bisby (Bot. Gaz. 69: 213. 1920) has excluded Uromyces 
hyalinus Peck from this group, although the species had been 
made the type of the genus Telospora (Résult. Sci. Congr. Bot. 
_ Vienne 346. 1906), which was intended to include only short — 
cycle species. In the Arthur Herbarium the sheets of U. hyalinus, 
which were studied by Bisby in preparing his paper, bear many 
notes signed by him. On June 20, 1916, he made a sectional 
drawing of pycnia from a ones of Seym. & Earle, Econ. Fungi 
Suppl. Bs5b, with the note: ‘“Pycnia are found associated with 
-uredinia, sometimes with telia; teliospores often in uredinia.” 
