BETULACEA. 
SILVA OF NORTH AMERICA. 
61 
ALNUS SITCHENSIS. 
Alder. 
LEAVES ovate, acute, sinuately lobed, doubly serrate, lustrous on the lower surface. 
Stamens 4. Nut broadly winged. 
Alnus Sitchensis. 
Alnus viridis, Bongard, Vég. Sitcha, 44 (not De Candolle) 
(August, 1832) ; Mém. Phys. Nat. Math. pt. ii. Acad. 
Set. St. Pétersbourg, ii. 162 (Vég. Sitcha). — Lyall, Jour. 
Linn. Soe. vii. 134, — Rothrock, Smithsonian Rep. 1867, 
454 (#1. Alaska).— Macoun, Cat. Can. Pl. 438. 
Alnus viridis, 8, Hooker, #7 Bor.-Am. ii. 157 (1839). 
Alnaster fruticosus, Ledebour, FV. Ross. iii. 655 (in part) 
(1849). 
Alnus viridis, 8 Sibirica, b Sitchensis, Regel, Nouv. 
Mém. Soc. Nat. Mose. xiii. 1388 (Monographia Betula- 
cearwm) (in part) (1861). 
Alnus viridis, 8 Sibirica, Regel, Russ. Dendr. pt. i. 50. 
(in part) (1870). 
Alnus occidentalis, Dippel, Handb. Laubholzk. ii. 158, f. 
78 (1892). — Koehne, Dewtsche Dendr. 114. 
Alnus rubra, Coville, Contrib. U. S. Nat. Herb. iii. 345 
(not Bongard) (1895). 
Alnaster Alnobetula, F. Kurtz, Bot. Jahrb. xix. 405 (£7. 
Chilcatgebietes) (not Schweinfurth) (1895). 
Alnus tenuifolia, Sargent. Silva N. Am. ix. 68 (in part) 
(not Nuttall) (1896). 
Alnus Alnobetula, Sargent, Silva N. Am. ix. 68 (in part) 
(not K. Koch) (1896). 
Alnus viridis, 5 sinuata, Regel, Bull. Soc. Nat. Mose. 
EXXVill. pt. ii. 422 (Gattungen Betula und Alnus) (in 
part) (1865) ; De Candolle, Prodr. xvi. pt. ii, 183 (in 
part). 
Alnus incana, var. virescens, Gorman, Péttonia, iii. 70 
(not Watson) (1896). 
Alnus sinuata, Rydberg, Bull. Torrey Bot. Club, xxiv. 190 
(1897) ; Mem. N. Y. Bot. Gard. i. 117 (Fl. Montana). 
A tree, sometimes forty feet in height, with a trunk seven or eight inches in diameter covered 
with thin close blue-gray bark which is bright red internally, and short slender nearly horizontal 
branches forming a narrow crown ; or often a shrub only a few feet tall spreading into broad thickets. 
The branchlets are slender and slightly zigzag, and when they first appear are puberulous and very 
glandular ; they are bright orange-brown, lustrous, and marked by numerous large pale lenticels during 
their first season, much roughened during their second year by large elevated crowded leaf-scars, and 
light gray-brown the following year. The winter-buds are acuminate, dark purple, covered, especially 
toward the apex, with close fine pubescence, and about half an inch long. The leaves are ovate, acute 
at the apex, full and rounded, often unsymmetrical, and somewhat oblique or abruptly narrowed and 
cuneate at the base, divided into numerous short acute lateral lobes, and sharply and doubly serrate, 
with straight glandular teeth; when they unfold they are glandular-viscid, and at maturity are 
membranaceous, yellow-green on the upper surface, pale and very lustrous on the lower surface, and 
glabrous or villose along the under side of the stout midribs, with short brown hairs which usually 
also form tufts in the axils of the numerous slender primary veins which extend obliquely to the points 
of the lobes; they vary from three to six inches in length and from half an inch to four inches in 
width, and are borne on stout grooved petioles abruptly enlarged at the base, and from one half to 
three quarters of an inch in length. The stipules are oblong or spatulate, rounded and apiculate at 
the apex, puberulous, and about a quarter of an inch long. The aments of staminate flowers are 
produced in pairs in the axil of the upper leaf, which is sometimes reduced to a small bract, and singly 
in the axil of the leaf next below it, and are nearly sessile; appearing in summer, they are about 
half an inch long and an eighth of an inch wide during the winter, with dark red-brown shining 
apiculate puberulous scales, and when the flowers open in spring, or at midsummer at high elevations, 
when the leaves are nearly one third grown, they are four or five inches long, with a puberulous light 
red rachis and pedicels, and ovate acute apiculate three-flowered scales. The calyx is four-lobed with 
