This section is from the book "Sub-Alpine Plants Or Flowers Of The Swiss Woods And Meadows", by H. Stuart Thompson. Also available from Amazon: Sub-Alpine Plants: Or, Flowers of the Swiss Woods and Meadows.
Trees or shrubs with alternate stipulate leaves. Flowers monoecious. Male flowers in drooping catkins, sepals 4 or less, stamens 2-4; female flowers 2-3, under each scale of a catkin; perianth o. Fruit indehiscent.
A large family chiefly found in the temperate regions.
Stamens 2; scales of female catkin thin, deciduous, trifid.
A small dwarf shrub. Leaves very shortly stalked, nearly orbicular, about 1/2 inch long, very obtuse, crenate or serrate. Catkins small and sessile, the males oblong, the females very short, erect.
Moors and bogs in the Alps and sub-Alps up to 6500 feet. May, June.
Central and Northern Europe, Northern Asia and Arctic America. British.
A small tree, 40-50 or rarely 70 feet high, with white papery bark and glabrous ovate-acuminate, doubly serrate leaves. Fruit broadly winged.
Europe, temperate and Arctic Asia; N. America (a variety).
A similar tree with narrower pointed leaves which are pubescent and finally only downy at the midrib. Fruit broadly winged.
Damp woods, peat-bogs and moors in the plains, sub-Alps and Alps. April, May.
Switzerland, Jura, Alps, Pyrenees; Central and Northern Europe, Caucasus, Northern Asia, Greenland.
Stamens 4. Scales of female catkin persistent, woody.
A shrub sometimes attaining the height of a small tree in the lower mountains. Leaves stalked, green, ovate-acute, doubly serrate, glabrous. Flowers in monoecious catkins, male cylindrical, drooping; female oval, stalked, 2-5 in erect racemes, not 1/2 inch long, forming a woody cone ripening the second year.
Mountains and clearings in the lower Alps, from 3000 to 6600 feet, especially abundant on granite and schist.
Central and Eastern Europe, Northern Asia and America.
A shrub or tree with silvery bark and oval-acute leaves doubly serrate, glabrous above, downy and grey beneath. Fruit not winged.
Damp woods, borders of streams, etc., up to 5000 feet. March, April.
Alps, Jura; Europe, temperate Asia, N. America.
This well-known tree has obtuse, almost orbicular leaves, which are shortly petioled and sticky at first on the upper side. Damp woods, by water, etc., up to 4000 feet. February to April.
Europe, temperate Asia, N. Africa. British.