UREDINALES OF GUATEMALA 
433 
A cosmopolitan rust of temperate regions. This is the first record 
for Central America, where it is doubtless rare. 
58. Skierka Holwayi Arth. sp. nov. (on Sapindaceae). 
Thouinidium decandrum Radlk. (?), Sanarate, Dept. Guatemala, 
Feb. 10, 1916, ii, III, 475. 
Thouinidium sp., Agua Caliente, Dept. Guatemala, Feb. 10, 191 7, 
o, II, III, 849 (type). 
Pycnia amphigenous, solitary or few in small groups, noticeable, 
reddish-brown, subepidermal, discoidal, 416-448 ix in diameter, 96- 
128 IX high; ostiolar filaments apparently wanting. 
Uredinia chiefly epiphyllous, encircling the pycnia in groups 1-5 
mm. across, round, 0.1-0.2 mm. in diameter, flask-shaped in cross sec- 
tion, covered by the greatly thickened epidermis, through which the 
dehiscence is by a small pore, the spores at first cohering in loose 
columns, soon falling apart and giving the spots a pulverulent, 
cinnamon-brown appearance; urediniospores oblong-fusiform or ellip- 
soid-fusiform, 19-26 by 43-60 IX when in alcohol or dry; wall golden- 
brown, 2.5-3 IX thick when dry or in alcohol, in water the outer, 
hygroscopic layer paler, swelling up to 7-10 ix, the apex beaked, 7-9 ix 
long in alcohol or dry, 10-15 ^x long in water, very finely and incon- 
spicuously verrucose when dry, appearing smooth when wet, the pores 
obscure, probably 2, equatorial. 
Telia hypophyllous, opposite the uredinia and similar to them; 
teliospores oblong-fusiform, 12-19 by 35-50 ix exclusive of the acute 
or filiform beak, the narrowed base with a distinct hilum, cohering in 
long columns 4-5 mm. long, 80-150 ix in diameter; wall colorless, or 
slightly yellowish, the inner layer i ix thick, the outer layer not notice- 
able in alcohol or dry, swelling in water to 3-9 ai and disintegrating, 
with the apex filiform, up to 100 /z, and likewise disintegrating, the 
base deciduous from the slender, inconspicuous pedicel, leaving a 
noticeable hilum. 
A very unusual rust, having the appearance of a Cronartium. The 
teliospores, however, are borne singly on pedicels from a flat hymenium, 
and breaking away are extruded in a long filament of agglutinated 
spores, held together by the mucilaginous outer layer of the spore wall. 
The genus was established by Raciborski for two species found in Java, 
the type species being on Burseraceae and the other on Euphorbiaceae. 
Another species was added by Hennings on Sapindaceae from the Con- 
go region of Africa. In these three species the spores of both stages are 
smaller than in the American form, and the urediniospores have more 
of the customary appearance of those of rusts in general. In the 
present species the urediniospores are large, and have an outer hygro- 
