ALNUS 



ALNUS 



253 



cc. Li's. plicate in the biul, the veins going straight to the 

 points of the larger teeth: cones 4-10, short- 

 stalked or sessile. 



D. Under side of Ivs. glaucous, not bearded: cones sessile 

 or short-stalked. 



8. incana, Willd. Shrub or tree, to 60 ft.: branches 

 pubescent: Ivs. oval or oblong-ovate, acute, 134~4 in. 

 long, doubly serrate, pubescent or nearly glabrous 

 beneath: cones 4-8, mostly sessile, Hin- long. North- 

 ern hemisphere, in different varieties. H.W. 2 : 13. 



Var. gla&ca, Ait. (A. glaxica, Michx.). Shrub, to 12 

 ft.: Ivs. often nearly glabrous beneath. N. Amer., Eu. 

 Em. 251. 



Var. vulgaris, Spach. Tree, to 50 ft.: Ivs. usually 

 densely pubescent beneath: cones 1 in. long. Eu., Asia. 



Var. pinnatiflda, Spach (var. laciniata, Hort.). Lvs. 

 pinnately lobed or cleft, with dentate lobes. 



9. tinctoria, Sarg. (.4. incdtia var. tinctbria, Hort.). 

 Fig. 165. Tree, to 60 ft.: young branchlets glabrous or 

 slightly pubescent: lvs. broadly ovate, 4-6 in. long, 

 membranaceous, coarsely doubly serrate, slightly lobed, 

 glaucous and rufously pubescent on the veins beneath. 

 Japan. G.F. 10:473 (adapted in Fig. 165). S.I.F. 1:19 

 (as var. glauca). — Handsome ornamental tree of very 

 vigorous growth, with large foliage. 



10. rftbra, Bong. (A. oregana, Nutt.). Tree, 40-50 

 ft.: lvs. oblong-ovate, 3-5 in. long, crenate-serrate, 

 slightly lobed, revolute on the margin, nearly glabrous 

 beneath; petioles and veins orange-colored: cones 6-8, 

 oblong. W. N. Amer. S.S. 9:454. Nutt., N. Amer. 

 S. 1:9. 



DD. Under side of lvs. green or brownish green, usually 



bearded. 



E. Cones upper sessile. 



11. rugSsa, Spreng. Smooth Aldeh. Shrub, to 25 

 ft.: young branchlets pubescent or nearly glabrous: lvs. 

 ovate or broadly elliptic to obovate, acute or obtuse, 

 2-5 in. long, doubly serrate and often sUghtly lobed, 

 beneath covered more or less with brownish pubescence 

 or glabrous: cones 4-10, the upper sessile, the lower 

 short-stalked, ovoid, about J^in. long. E. N. Amer. 

 Mx. 3:4. Var. sernilata, Winkl. (A. serruh'itn, Willd.). 

 Branchlets glabrous or nearly so: lvs. usually obovate, 



obtuse, finely and doubly serrulate, glabrous or nearly 

 glabrous beneath. Em. 248. — By most European 

 botanists this variety is considered a distinct species, 

 but, though the extreme forms seem quite distinct, they 

 are connected by all kinds of intermediate forms. In 

 flower, A. rugosa is easily distinguished from A. incana 



165. Alnus tinctoria. ( X H) 



166. Alnus glutinosa. ( X. Vi) 



by the pistillate catkins which are upright in A. rugosa, 

 nodding in A. incana. 



EE. Cones all distinctly peduncled. 

 12. glutinosa, Gaertn. (A. vulgaris, HiU. A. rotundi- 

 folia, Mill. A. commiinis, Desf.). Black Alder. Fig. 

 1 66. Tree, to 70 ft. : lvs. orbicular or obovate, rounded or 

 emarginate at the apex, 2-5 in. long, irregularly obtusely 

 serrate, with 5-7 pairs of veins, nearly glabrous beneath, 

 glutinous when unfolding: cones distinctly peduncled. 

 Eu., N. Afr., Asia, naturaUzed in some localities in N. 

 Amer. H.W. 2:12. H.T. 130.— A vigorously grow- 

 ing tree with dark green, dull foliage, valuable for 

 planting in damp situations. Commonly planted in 

 many forms: Var. afirea, Versch. Lvs. yellow. I.H. 

 13:490. Var. denticulata, Ledeb. {A. oblongata, Willd.). 

 Lvs. usually cuneate, serrulate. S. Eu. Var. barbata, 

 Callier (A. barbata, C. A. Mey.). Lvs. ovate, acute, 

 pubescent on the veins beneath. Caucasus. Var. 

 imperialis, Desf. Lvs. deeply pinnately lobed with lan- 

 ceolate or nearly Unear lobes. Var. incisa, Willd. (var. 

 oxyacanlhifblia, Spach). Lvs. small, deeply incised, 

 like those of Cratsegus oxyacantha. Var. laciniata, Willd. 

 Lvs. pinnately lobed; lobes oblong. Var. rubrinervia, ' 

 Dipp. Lvs. large and shining, with red nerves and 

 petioles: pyramidal tree of vigorous growth, very 

 handsome. 



.4. acuminata, HBK. Tree; Ivs. usually ovate and pubescent be- 

 neath, doubly serrate. Cent. Amer., north to Ariz. — A. cremastogytie, 

 Burkill. Tree: young branchlets glabrous; lvs. oblong-obovate, 

 glabrous, sharply serrate, 3^ in. long: cones cylindric, solitary on 

 slender peduncles, about 1 J^ in. long. W. China. — Recently intro., 

 probably not hardy N. — A. firma, Sieb. & Zucc. (A. Sieboldiana, 

 Mats.). Allied to A. yasha. Tree: lvs. ovate, or ovate-oblong, 

 acute, rounded at the base, with 10-15 pairs of veins, 3-5 in. long: 

 cones about 1 in. long, solitary on a peduncle }i-l in. long". Japan. 

 S.I.F. 2:12. — A. frulicdsa. Rupr. (A. viridis var. sibirica, 

 Regel). Allied to A. viridis. Shrub; lvs. broadly ovate or elliptic- 

 ovate, usually rounded at the base, nearly doubly or sinuately 

 serrate. Siberia, Corea. — A. hirsuta, Turcz. (A. incana var. 

 hirsuta, Spach). Allied to A. tinctoria. Tree; young branchlets, and 

 petioles tomentose: lvs. suborbicular to elliptic, acutish, dentic- 

 ulate and slightly lobed, ferrugineously tomento.se beneath. Japan, 

 Manchuria. — A. jorullensis. HBK. Allied to A. acuminata. Lvs. 

 oblong-lanceolate, coarsely dentate. Cent. Amer. — A. mollis, 

 Fernald. Closely allied to A. crispa. Shrub or small tree: branchlets 

 pubescent: lvs. pubescent beneath, 2-4 in. long. N.E. Amer., west 

 to Lake Winnipeg, south to Mass. — A. nitida, Endl. Tree, to 100 

 ft.; Iva. ovate to ovate-oblong, short-acuminate, not plicate, 3-4 

 in. long, entire or remotely serrulate, bright green and lustrous 



