Arthur: Uredinales of Costa Rica 147 



Pycnia hypophyllous, few, associated with small groups of 

 aecia, subepidermal, ovoid, 24-48 /x broad by 48-67 fi high. 



Aecia hypophyllous, rarely in small groups associated with 

 pycnia, usually scattered by ones and twos without pycnia, short- 

 cylindric, 0.1 mm. or less across, 0.1-0.3 mm - high; peridium 

 white, the margin recurved, erose ; peridial cells rhombic, 12-13 

 by 16-19 /jl, abutted, the walls evenly 1.5-3 /x thick, the outer one 

 smooth, the inner one very finely verrucose ; aeciospores angu- 

 larly globoid or ellipsoid, 13-16 by 16-19/x; wall colorless, 1— 1.5/* 

 thick, finely and closely verrucose. 



Five species of Aecidium have previously been described on 

 Phyllanthus, from all of which the present collection apparently 

 differs in having the aecia conspicuously scattered. Microscopic 

 comparison has been made with A. detritum P. Henn. from Uru- 

 guay, and A. favaceum Arth. from Porto Rico, both of which 

 have much larger spores. The descriptions of A. Phyllanthi P. 

 Henn. from New Guinea, A. phyllanthinum Syd. from Assam, 

 and A. luzoniense P. Henn. from the Luzon, appears to be dis- 

 tinctive, and unlike any of the American forms. 



no. Aecidium tubulosum Pat. & Gaill. (on Solanaceae) 

 Solanum torvum Sw., Orotina, Dec. 31, 191 5, 341. 



A common aecial rust of the tropics on Solanum torvum and 

 closely related hosts, which according to the observations of 

 Whetzel and Olive in Porto Rico doubtless is one stage of the 

 grass rust, Puccinia substriata. 



in. Aecidium tenerius Arthur & Holway sp. nov. (on 

 Solanaceae) 



Acnistus arborescens Schlecht., San Jose, Jan. 3, 1916, 362. 



Aecia hypophyllous, scattered or loosely grouped, round, 0.3-0.8 

 mm. across ; peridium inconspicuous, usually hidden by the per- 

 sistent epidermis, or evanescent ; peridial cells long and narrow 

 in side view, often becoming curved, 5-9 by 29-48^, the outer 

 and inner walls quite thin, the inner very finely and inconspicu- 

 ously verrucose ; aeciospores globoid or ellipsoid, 19^23 by 24- 

 32 {*,; wall colorless, 2-2.5^ thick, frequently slightly thicker both 

 above and below, inconspicuously verrucose, appearing smooth 

 when wet. 



The delicate peridium gives a very different appearance to this 



