BETULA 85 
limestone soils, it becomes abundant at the higher altitudes only, as a rule. On chalk rock, it is 
absent. Frequent in Ireland, both in the plain and on the hills. Commonly planted. 
Arctic and northern Europe, northwards to Lat. 67° 40' N. ; central Europe (up to 2050 m.) ; 
northern Portugal, north-western Spain, northern Italy; Asia Minor; northern Asia; North America, 
southwards to the great lakes and New England. This species reaches further northwards than 
any other tree in Europe. 
B. TtCLTlCL x pubescens Giirke Plant. Eur. ii, 50 (1897); Winkler in Pflanzenr. iv, pt. 61, 93 (1904); 
Ascherson und Graebner Syn. iv, 410 (1911). 
leones: — Camb. Brit. FI. ii. Plate 87. 
Two forms of this hybrid may be distinguished, (A) x B. intermedia and (B) x B. alpestris. 
(A) x B. intermedia Giirke Plant. Eur. ii, 50 ( 1 897) ; Winkler in Pflatizenr. iv, pt. 61, 93 (1904); Ascherson 
und Graebner Syn. iv, 41 1 (1911); B. alba var. intermedia Wahlenberg FI. Suec. ii, 624 (1826); B. nana var. 
intermedia Hartman Handb. Skand. FI. 341 (1820); B. intermedia [Thomas ex] Gaudin FI. Helv. vi, 176 (1830); 
Regel in DC. Prodr. xvi, pt. ii, 170 (1868). 
leones: — Reichenbach Icon, xii, t. 624, fig. 1283, as B. intermedia ; FI. Dan. t. 2852, as B. intermedia. 
Camb. Brit. FI. ii. Plate 87. (a) Shoot with ripening catkins. Forfarshire (E. S. M.). (b) Fruiting bracts 
(one enlarged). ( c ) Winged achenes (one enlarged). ( d — e) See x B. alpestris. 
Exsiccata : — v. Hayek {FI. Stir. Exsicc.), 521, as B. intermedia ; Herb. FI. Ingric. ix, 584 (partim), as 
B. alpestris ; herb. Marshall, 361 g, 1887, 2823, 2949, 2950, 3384. 
Small tree or large shrub, attaining a height of about 2^5 — 4 m., much branched, usually densely 
branched. Bark dark brown, usually shining. Young branches usually glabrous except at the tips 
which are pubescent and glandular. Petioles about a third to half as long as the laminae. Laminae 
suborbicular or suborbicular-rhomboidal, sometimes broader than long, truncate or broadly cuneate 
at the base, sharply and irregularly dentate, acute or obtuse, about 1*5 — r8 cm. long and ro to 
1 ’5 broad, ultimately glabrous, subcoriaceous, dark green above, grey-green and strongly reticulate 
underneath. Staminate catkins not seen. Pistillate catkins usually numerous, pedunculate, about 
twice to four times as long as the peduncles, erect or ascending, short and rather stout (about 1*5 — 
2'o cm. long and 1*2 broad). Stigmas purple, one-third to one-half as long as the ripening ovary. 
Bracts small (about 3 mm. broad), rather cuneate towards the base ; lobes ciliate, obtuse, lateral 
ones ovate or rounded, ascending. Achene and wing variable, sometimes as in B. pubescens and 
sometimes much narrower. 
Rare, and hitherto only found in Scotland as isolated individuals ; ascending to 650 — 700 m. in the Grampians ; 
more frequent than x B. alpestris. Argyllshire (Professor J. W. H. Traill in Ann. Scot. Nat. Hist. 180 (1906)), 
Forfarshire (stream, near Bachnagairn, Clova), Aberdeenshire (near the head of the burn in Glen Callater, Glen 
Slugain, Invercauld Forest, Braemar), Ross-shire (bank of a tributary of the Garbad burn, Wyvis Forest, near 
Garve), Sutherlandshire (close to the ferry at Cashil Dhu, at the head of Loch Hope). 
Iceland, Scandinavia, Germany (one station), Switzerland (Jura). 
(B) x B. alpestris Giirke Plant. Eur. ii, 50 (1897); Winkler in Pflanzenr. iv, pt. 61, 93 (1904); Ascherson 
und Graebner Syn. iv, 41 1 (1911); B. humilis Hartman Handb. Skand. FI. 328 (1838) non Schrank ; B. alpestris 
Fries Veg. Scand. i, 212 (1846); Regel in DC. Prodr. xvi, pt. ii, 172 (1868) partim; Kindberg in Bot. Notiser 
121 (1909); B. nana var. alpestris Regel Monogr. Betul. 45 (1861) partim; B. humilis var. Watsoni Spach in Ann. 
Sc. Nat. s£r. 2, xv, 194 (1841). 
leones: — Watson Dendrol. Brit, ii, t. 154, as B. fruticosa ; Reichenbach Icon, xii, t. 622, fig. 1280, as 
B. fruticosa var. humilis. 
Camb. Brit. FI. ii. Plate 87. (d) Fruiting bracts (one enlarged), (e) Winged achenes (one enlarged). 
Exsiccata: — Ahlberg, as B. alpestris ; Fries, v, 60, as B. humilis ; Herb. FI. Ingric. ix, 584 (part.) as B. 
alpestris ; herb. Marshall 494, 2449, 2951. 
Shrub or undershrub, scarcely attaining a height of 2 m. and usually much lower. Bark dark 
brown, shining. Internodes short. Young branches glabrous, rugose and slightly glandular at the 
tips, shorter than in x B. intermedia. Laminae rather smaller than in x B. intermedia , serrations 
more regular, shallower, blunter. Staminate catkins not seen. Pistillate catkins pedunculate, smaller 
than in x B. intermedia. Bracts scarcely differing from those of B. nana. Wing of fruit narrower 
than the achene, sometimes rudimentary or even absent. 
Very rare ; Perthshire (Rannoch Moor, near Kingshouse, at 300 m.), ? Aberdeenshire (wet peaty ground, 
Lochnagar, descending towards the Dhu Loch, at 840 m.), Sutherlandshire (at the northern base of Ben 
Laoghal, near Tongue, at about 250 m.). 
