1905] ARTHUR—RUSTS FROM MEXICO 393 
This collection differs slightly from the type in havi ing heads almost or quite 
smooth, and with paraphyses fewer and paler. 
23. RAVENELIA LEUCAENAE Long.—On Leucaena diversijolia 
Benth., Etla, State of Oaxaca, Nov. 13, 1903, no. 5408: L. esculenta 
DC., Etla, State of Oaxaca, Nov. 1 3, 1903, no. 5413; Iguala, State 
of Guerrero, Nov. 3, 1903, no. 5311: Leucaena sp., Guadalajara, 
Sept. 25, 1903, no. 5044; and Tehuacan, State of Puebla, Nov. 7, 
1903, NO. 5340. 
There appears to be considerable uncertainty in the exact determination of 
the species of Leucaena. Although these numbers have been submitted to com- 
petent i the correctness of the specific names employed here cannot 
be vouched for. 
24. RAVENELIA EXPANSA Diet. & Holw.—On Acacia filiculoides 
(Cav.) Trel. (A. filicina Willd.), Iguala, State of Guerrero, Nov. 3, 
1903, no. 5312: A. cochliacantha Humb. & Bonp., Iguala, State of 
Guerrero, Nov. 3, 1903, no. 5315; Tehuacan, State of Puebla, Nov. 
8, 1903, no. 5353: Acacia sp., Yautepec, Oct. 24, 1903, no. 5237. 
25. RAVENELIA sILIQUAE Long.—On Acacia pennatula Benth., 
Etla, State of Oaxaca, Nov. 14, 1903, NO. 5395. 
The type was seen by Mr. Lone only on the fruit, but the present collection, 
Which does not differ in any perceptible way from the type, only shows rust on 
the leaves. No teleutospores could be found. 
26. Ravenelia gracilis, n. sp—Spermogonia amphigenous, puncti- 
form, crowded in groups, prominent, subcuticular, hemispherical, 
60-100# broad and half as high: uredosori epiphyllous, scattered, 
less than o.25™™ in diameter, nearly round, mamillose, dehiscent 
by central, irregular rupture, the encircling epidermis forming an 
aecidioid cup, paraphyses peripheral, or also intermixed with the 
Spores; uredospores elliptical or obovate-oblong, 16-21 by 30-404, 
wall rather thin, 1.5-2.5, golden-brown, strongly and evenly echinu- 
late, pores 4-6, equatorial; paraphyses hyphoid, 7-10 by 40-604, 
Somewhat contorted, smooth, thin-walled, nearly or quite colorless: 
teleutosori like uredosori, but without paraphyses; teleutospore- 
eads chestnut-brown, 5—7 cells across, 75-100” in diameter, each 
Spore bearing 4~7 slender, nearly colorless tubercles, 3-4 high; 
cysts delicate, appressed beneath the head, extending from periphery 
to pedicel, united laterally; pedicel short, colorless, deciduous.— 
