ALNUS 185 



above, pale, very lustrous green beneath ; smooth or with hairs along the 

 midrib, and tufts in the vein-axils ; viscid when young ; stalk stout, grooved, 

 to | in. long. Male catkins 4 to 5 ins. long. Sargent distinguishes this 

 species among American arborescent alders by the flowers opening with or 

 after the leaves, by the female catkins being enclosed during the winter, 

 and by the lustrous under-surface of the leaves. It is the Western American 

 representative of A. viridis. 



A. SUBCORDATA, C. A. Meyer. CAUCASIAN ALDER. 



A tree up to 60 ft. high ; young shoots downy, angled toward the end ; 

 buds stalked. Leaves ovate or oval, with a rounded or slightly heart-shaped 

 base, and a short, abrupt point ; 3 to 6 ins. long, 2 to 4 ins. wide ; irregularly 

 and often doubly toothed towards the apex, more finely so towards the base ; 

 dark green and almost smooth above, paler and downy beneath, especially 

 along the midrib and veins ; primary veins in eight to ten pairs ; stalk f to 

 over i in. long, downy. Male catkins in clusters of four or five, very slender, 

 up to 6 ins. long, expanding sometimes as early as December. Fruits f to 

 \\ ins. long, nodding, solitary up to as many as five together. 



Native of the Caucasus and Persia ; introduced, according to Loudon, 

 in 1838, and raised that year from seed in the Birmingham Botanic 

 Garden. It is a handsome, fine-foliaged alder, retaining its leaves until the 

 end of November. There is a specimen over 50 ft. high on the banks of the 

 lake at Kew. A. cordifolia is the only other species with which it is likely to 

 be confused, but that differs markedly in its smooth shoots, its less downy, 

 simply toothed, deeply cordate leaves, and larger fruits. 



A. TENUIFOLIA, Nuttall. 



A shrub or tree, up to 30 ft. high, with a trunk i| to 2 ft. in girth ; young 

 shoots red, and covered at first with a fine down, smooth by autumn ; buds 

 stalked, downy. Leaves oval or ovate, 2 to 4 ins. long, two-thirds as wide, 

 rounded or slightly heart-shaped at the base, pointed ; veins in about ten 

 pairs, each vein ending at the point of a toothed lobe ; dark green above, with 

 down on the midrib and nerves ; paler green and more or less downy beneath; 

 stalk \ to i in. long, downy. ' Male catkins expanding in March in clusters 

 of three or four, each \\ to i\ ins. long. Fruits narrowly egg-shaped, ^ to f 

 in. long, three to five in a cluster. 



Native of Western N. America, from British Columbia to California. It 

 is, perhaps, most nearly allied to A. oregona, but the leaves are not greyish 

 beneath, the male catkins are shorter, and the fruits smaller. According to 

 Sargent, the wing of the seed in A. tenuifolia is reduced to a narrow border, 

 whilst it is broad in A. oregona. 



Var. OCCIDENTAL^, Callier (A. occidentalis, Dteck). This distinct 

 variety was introduced to Europe by Mr A. Purpus, and first cultivated at 

 Zoeschen in Germany by Dr Dieck, from whom it came to Kew in 1889. The 

 leaves are larger than in the type, and on young trees very large ; at Kew 

 they have been 7 ins. long by 5 ins. wide, and I have leaves from a tree 

 in Sir Archibald Buchan - Hepburn's garden at Smeaton, N.B., even 

 broader. Veins in ten to twelve pairs, the entire under-surface at first downy. 

 Fruits f to f in. long. Native of British Columbia and Oregon. 



A. VIRIDIS, De Candolle. GREEN ALDER. 



(A. alnobetula, Koch ; A. crispa, Pursh.') 



A shrub 3 to 10 ft. high, forming a cluster of erect stems ; young branchlets 

 viscid and usually smooth. Leaves viscid, ovate, or roundish oval, i to 3^ ins. 



