CATALOGUE. 239 
Ait., var. ovcIDENTALIS, Watson (U. dioica, L., var. occidentalis, Watson, vol. 
v, King’s Report, p. 321), Utah. 
Urrica piorca, L.—Western New Mexico, Loew. 
Urtica Brewert, Watson (Proc. Amer. Acad. x, p. 348).—Perennial, 
erect, rather slender, spinulose; leaves quite thin, very coarsely and some- 
what irregularly toothed, 3-5’ long, 1-14’ wide, cuneate, rounded, or sub- 
cordate at base; petioles slender, 14-3’ long; flowering panicles loose, 
about as long as the petioles; ovate achenium $’ long, included in the 
obovate, hispid perianth. Very variable-—Southern Colorado (71).—Puate 
XXV. Natural size. Fig. 1. Staminate flower. Fig. 2. Pistillate flower. 
Fig. 3. Achenium, enclosed by the large inner sepals. Fig. 4. Calyx 
opened, showing mature achenium. All enlarged about 10 diameters. 
Humutvus Lurutus, L.—Utah and Colorado (53). 
BETULACEZ. 
BeTULA OCCIDENTALIS, Hook.—Northern Nevada, Utah, and Colo- 
rado (841). 
Betuta GLanputosa, Michx.—Colorado (838, 839). 
Anus incana, Willd., var. guauca, Ait.—Arizona, Utah, and Colo- 
rado (840), 
ALNUS OBLONGIFOLIA, Torr. (in Bot. Mex. Bound. p. 204).—‘“ Branches 
smooth and shining; leaves oblong-lanceolate, acute at each end, some- 
what doubly serrate, smooth above and minutely pubescent beneath, with 
surfaces green; nutlets wingless. Tree 30° high. Leaves 24-34’ long 
-and 1-14’ wide, unequally serrate, serratures glandular at the tip. Petiole 
about one-third as long as the lamina. Catkins somewhat paniculate, ovate. 
Nutlets orbicular-obovate, without any trace of a wing.” I have not seen 
the plant, and hence have quoted the above from Bot. Mex. Bound. /. ¢.— 
Arizona. 
PLATANEZ. 
Piatanus rAcEMosA, Nutt—Leaves broadly cordate, deeply 5-cleft, 
divisions sharp pointed, lanceolate, the lower smaller, sometimes only 
3-cleft from suppression of the lowest lobes. Upper surface at first covered 
_ with branching, yellow hairs; under surface always whitish woolly ; fertile 
