72 
(Bull. Soc. Bot. Belg. xxix. 17-65). 
This is an annotated list of all the species of Acer recognized 
by the author. He differs materially from the last publ 
monograph of the genus—that of Herr. Pax in Engler s Bot. 
Jahr. 1885-1886, with supplemental notes in the same journal in 
1889—recognizing considerably fewer species, but an enormous 
number of sub-species, varieties and sub-varieties, many of them 
purely garden sports. As regards our North American Species, 
both he and Herr. Pax, from paucity of material and unfamiliarity 
with the trees themselves and their geographical distribution, have 
clearly fallen into many errors, and we cannot see that the paper 
here noticed is of any value to American botany. 
Relation of the Mexican Flora to that of the United States. Set- 
eno Watson. (Proc. Am. Ass. Ad. Sc. xxxix. 291). 
Rusbya, a new genus of the Vacciniacee from Bolivia. N. 1. 
Britton. (Proc. Am. Ass. Nat. Sci. xxxix. 332). 
Saccorhiza dermatodea—Concerning the Life-history of. WV. A. 
Setchell. (Proc. Am. Acad. Arts and Sci. xxvi. 177-217 
1891, reprinted). 
An interesting contribution from Prof. Farlow’s laboratory; 
describing the histology and morphology of a circumpolar alga, 
with its bibliography and history; illustrated by two finely lith- 
ographed plates. 
Spirea discolor, var. ariefolia. J. G. Jack. (Gard. and Fot. 
iv. 615, 616; fig. 98). 
Thelephorei—Notes on. M. C. Cooke. (Grevillea, xx. 33-35) 
New Brazillian species are described in the genera Beccariel- 
la and Hypolyssus. 
Uncinula spiralis—- Observations on the life-history of. B. T. Gallo- 
way. (Proc. Am. Ass. Ad. Sci. xxxix. 333). 
Uromyces trifolia—The trimorphism of. J. K. Howell. (Proc: 
Am. Ass. Ad. Sci. xxxix, 330). 
Weeds—The migration of. Byron D. Halsted. Proc. Am. Ass, 
Ad. Sci. xxxix. 304). 
Work of the Botanical Division of the Department of A griculture 
F. V. Coville. (Proc. Am. Ass. Ad. Sci. xxxix. 348). 
