Arthur: Uredinales of Porto Rico 
327 
1 01. Uredo rubescens sp. nov. 
Uredinia hypophyllous, irregularly grouped on indefinite pale 
spots, round, small, 0.2-0.4 mm. across, soon naked as if by a 
central pore, surrounding epidermis scarcely noticeable except 
for a reddish coloration, subepidermal ; paraphyses peripheral, 
cylindrical, hyphoid, incurved, scarcely rising above the spore- 
mass, the wall colorless and smooth ; urediniospores ellipsoid, 
18-19 by 25-28 ju,; wall pale cinnamon-brown, 1.5 /x, rather closely 
and strongly echinulate, the pores obscure. 
On Moraceae: 
Dorstenia Contrajerva L., Camuy, Nov. 22, 5011. 
A well marked form. Although the paraphyses are not 
readily found except by sectioning, yet they are indicated under 
a hand lens as a pale circle bounding the sorus. The spores 
either have very short pedicels or are formed in chains, of which 
only one spore matures at a time. Even the best sections do not 
decide the matter, but it must be left to be worked out from a 
study of the cytological development. 
102. Uredo Bixae sp. nov. 
Uredinia epiphyllous, numerous, scattered singly or in groups 
of two to four on small purple spots, very small, about o.i mm. 
across, soon uncovered, ruptured epidermis inconspicuous, the 
paraphyses showing as a whitish circle, subepidermal ; paraphyses 
peripheral, numerous, incurved, rising but little above the surface 
of the leaf, clavate-cylindric, 9-10 by 27-35 /x, the walls color- 
less, smooth, less than i fji. inside and 2-5 /u, outside ; urediniospores 
obovoid, 16-23 by 26-7,7 jj-', wall nearly colorless, thin, i or less, 
closely and finely echinulate, the pores obscure. 
On Bixaceae; 
Bixa Orellana L., Adjuntas, March 2, 462. 
The host is a native of tropical America, but has been culti- 
vated and become wild in tropical regions throughout the world. 
It supplies the coloring matter of commerce called annatto, much 
used in butter. 
The sori are very small, numerous and deep-seated, but in the 
specimen examined, they are much parasitized and the spores 
few. 
