332 
J. C. ARTHUR 
lected by Kellerman on Salix Humholdtiana H. B. K., near P^talul, 
Dept. Solola, Feb. i6, 1906, II, S473 (Kellerm. Fungi Sel. Guat. 2), 
and reported by Kern in Journ. Myc, /. c. The willow, 5. Humhold- 
tiana, forms conspicuous groves in the middle altitudes. 
10. Melampsora ARCTiCA Rostr. (on Salicaceae). 
Salix taxifolia microphylla Schn., Huehuetenango, Jan. 22, 191 7, 
n, 7(>3. 
This species of willow rust has small urediniospores, and is a some- 
what common form in northern regions, especially in the mountains. 
It has aecia on Abies. 
11. Phakopsora Vitis (Thiim.) Syd. (on Vitaceae). 
Vitis caribaea DC, Guatemala City, Jan. 7, 1917, II, 680. 
This is the first record of the rust occurring upon native grapes in 
America. The spores from this specimen in general are smaller than 
usual, and the paraphyses are noticeably thickened on the convex side. 
The latter character is not mentioned in the diagnosis given in the 
North American Flora (7 : 102), where it is listed under the name 
Pliysopella Vitis. It is a common tropical rust, whose life history is 
not fully known. 
12. Spirechina RuBi (Diet. & Holw.) Arth. (on Rosaceae). 
Rubus laxus Rydb., Huehuetenango, Jan. 21, 1917, II?, Ill, 75<5. 
Rubiis Pringlei Rydb., Volcan de Agua, 7,000 feet alt., Dept. 
Sacatepequez, Jan. 13, 1915, II2, 80; same March 7, 1916, II2, 
559. 560. 
Rubus sp., San Rafael, Dept. Guatemala, Jan. 7, 1915, II2, 17, 33; 
Quezaltenango, Jan. 13, 1917, O, Hi, II2, HI, 746. 
Not until the fine specimen of this rust on Rubus laxus was exam- 
ined did the real differences between primary and secondary uredinia 
in this species manifest themselves. In this specimen the under sur- 
face of the leaf is evenly covered with orange telia, the color coming 
from the spore contents, the walls being colorless, while the upper 
surface is well covered with secondary uredinia, of course unaccom- 
panied with pycnia. All the other collections except one here listed 
proved to have secondary uredinia only. Comparing these collections 
with others from Mexico, it was not difficult to make out that in this 
species both primary uredinia (with pycnia) and secondary uredinia 
(without pycnia) are epiphyllous, and do not noticeably differ mor- 
phologically either in sori or spores. The spores of both stages origi- 
