Part 6, 1921] AECIDIACEAE 423 
often appearing vertically striate, the pore of lower cell next to septum, usually with the wall 
much thickened; pedicel colorless, delicate, fragile, short. 
ON CaRDUACEAE: 
Baccharis oaxacana Greenman, Oaxaca. 
TYPE LOcaLItTy: Mt. Oaxaca, Mexico, on Baccharis oaxacana. 
DistRIBUTION: Known only from the type locality. 
239. Dicaeoma evadens (Hark.) Arthur & Jackson. 
Coleosporium Baccharidis Cooke & Hark. Grevillea 9:7. 1880. Not Eriosporangium Baccharidis 
Bertero 1854, nor Dicacoma Baccharidis Arth. & Jacks. 1920. 
Puccinia evadens Hark. Bull. Calif. Acad. 1:34. 1884. 
Caeoma Negerianum Dietel, Bot. Jahrb. 22: 357. 1896. 
Eriosporangium evadens Arth. Résult. Sci. Congr. Bot. Vienne 343. 1906. 
O. Pycnia amphigenous and caulicolous, scattered among the aecia on leaves and 
younger branches, inconspicuous, honey-yellow, globoid or ovoid, 150-175 u in diameter. 
I. Aecia amphigenous, or more commonly caulicolous, causing fusiform or irregular swell- 
ings of the branches, sometimes forming witches’ brooms, scattered, oblong or oblong-linear, 
0.5-1 mm. wide by 1-4 mm. long, early dehiscent, at first orange-colored, drying to a dirty- 
white, pulverulent, ruptured epidermis or cortex overarching, when the spores fall away show- 
ing pits or fissures; aeciospores irregularly oblong or oblong-fusiform, 22-26 by 35-60 u, often 
narrowed and acute at both ends, but especially above; wall pale-yellow or quite colorless, 
moderately thick, 2-3 u, somewhat thicker above, 3-9 », noticeably but finely verrucose, with 
thickly set and irregular warts. 
II. Uredinia chiefly hypophyllous, scattered, usually few, round or oblong, 0.1-0.3 mm. 
long, soon naked, orange-colored, becoming pale, somewhat pulverulent, ruptured epidermis 
often overarching, otherwise inconspicuous; urediniospores broadly ellipsoid, obovoid-ellipsoid, 
or nearly globoid, 23-27 by 27-35 4; wall thin, 1.5-2y, nearly colorless, finely and rather 
sparsely verrucose-echinulate with points about 3 4 apart, the pores small, very indistinct, 
apparently more than 4 and scattered. 
III. Telia chiefly hypophyllous, and to some extent on the young branches, scattered, 
round, 0.3-1 mm. across, soon naked, pulvinate, pale cinnamon-brown, or cinereous by germi- 
nation, ruptured epidermis inconspicuous; teliospores oblong or obovoid-oblong, 27-32 by 
48-63 », rounded at both ends, or somewhat narrowed below, somewhat constricted at septum; 
wall pale-brownish, or almost colorless, smooth, thin, 1.5-2, usually thicker at apex, 
3-6 yu; pedicel colorless, or slightly tinted, terete, 6-10 « in diameter, thin-walled, once to twice 
length of spore. 
On CARDUACEAE: 
Baccharis consanguinea Greene, California. 
Baccharis Emoryi A. Gray, Arizona. 
Baccharis halimifolia I,. (cult.), North Carolina; Cuba. 
Baccharis pilularis DC., California. 
Baccharis pteronioides DC., Michoacan. 
Baccharis salicina T. & G., New Mexico. 
Baccharis sarothroides A. Gray, Arizona. 
Baccharis thesioides H. B. K., Arizona. 
Tyrer LocaLity: San Francisco, California, on Baccharis pilularis. 
DIstRiBUTION: Central California to New Mexico, and southeastward through Mexico and the 
West Indies; also in South America. : 
Exsiccati: Barth. Fungi Columb. 2761, 2762; Barth. N. Am. Ured. 1713, 1912; Ellis & Ev. 
Fungi Columb. 53; Ellis & Ev. N. Am. Fungi 1843; Rab.-Wint. Fungi Eur. 3208; Sydow, Ured. 
1716. 
240. Dicaeoma Baccharidis (Dietel. & Hoilway) 
Arthur & Jackson. 
Puccinia Baccharidis Dietel & Holway; Dietel, Erythea 1: 250. 1893. Not Evisporangium Bac- 
charidis Bertero, 1854. 
Cacoma punctato-striaium Dietel & Neger, Bot. Jahrb. 22: 357. 1896. 
Eriosporangium punctato-striatum Arth. N. Am. Flora 7: 213. 1912. 
O. Pycnia amphigenous, numerous, crowded in small orbicular groups, comparatively 
large, punctiform, globoid-flask-shaped, 125-175 u in diameter; pycniospores globoid, 2-3 4 
in diameter. 
I. Aecia hypophyllous and caulicolous, when on leaves in orbicular groups surrounding 
