424 
J. C. ARTHUR 
23-29 iJi\ wall cinnamon-brown, moderately thick, 1.5-2 ^u, moderately 
echinulate, the pores 4, equatorial. 
Telia unknown. 
This rust appears to differ from all species so far described, and 
although without telia, requires to be independently named. Of the 
various Acacia-Leucaena-Calliandra rusts this is most like R. gracilis 
Arth., first reported from Mexico and recently found by Long in 
Texas (Bot. Gaz. 64: 66), but has smaller spores, with fewer pores. 
29. Ravenelia distans Arthur & Holway sp. nov. (on Mimosaceae). 
Genus and species undetermined, Retalhuleu, Feb. 26, 1916, ii, 
Urediniospores in the telia, lance-ovoid, 12-15 by 19-26 /z, usually 
acute above, somewhat narrowed below; wall cinnamon-brown, thin, 
I IX, much thicker above, 3-7 ju, moderately echinulate, the pores 4, 
equatorial. 
TeHa hypophyllous, scattered, round or oblong, 0.2-0.5 mm. 
across, early naked, subepidermal, chestnut-brown, ruptured epider- 
mis evident; teliospore-heads chestnut-brown, 4-6 cells across, 55- 
75 IX in diameter, each spore with 6-8 semihyaline spines, about 3 ix 
long; cysts adnate to the lower side of the marginal cells. 
This species has urediniospores of characteristic form. It is close 
to R. Pazschkeana Diet, on Calliandra from Brazil, but has smaller 
urediniospores and larger teliospore-heads composed of more spores. 
The leaves of the host have much the appearance of those of Mimosa. 
30. Ravenelia bizonata Arthur & Holway sp. nov. (on Mimosaceae) • 
Calliandra Hoiistoni Benth., Guatemala City, March 16, 1916, II, 
iii, 584 (type). 
Calliandra sp., Huehuetenango, Jan. 22, 1917, II, III, 762. 
Uredinia epiphyllous, scattered or somewhat grouped, round or 
oval, 0.2-0.4 mm. across, early naked, subcuticular, pulverulent, dark 
chestnut-brown, ruptured cuticle inconspicuous; paraphyses inter- 
mixed with the spores, capitate or clavate-capitate, 15-19 by 23-48 
the wall golden brown above, colorless below, 1-1.5 m thick, much 
thicker above, 7-10 ix\ urediniospores elhpsoid or obovoid, 15-19 by 
20-26 }x\ wall dark cinnamon-brown above, paler below, thin, 1-1.5 ix, 
sometimes slightly thicker above, very finely and closely echinulate 
below, usually smooth at apex, the pores 6-8 in two zones, one equa- 
torial, the other subequatorial. 
Telia usually epiphyllous, scattered, round, 0.1-0.3 mm. across,* 
soon naked, subcuticular, chestnut-brown, ruptured cuticle noticeable; 
teliospore-heads hemispherical, 4-6 cells across, 55-75 m in diameter, 
each spore with 2-4 colorless tubercles, 3-10 fx long; cysts attached to 
the lower side of each marginal spore. 
