A VENA 
255 
L. (the bird’s-nest fern) is an interesting epiphyte of the Old World 
tropics. It bears a rosette of leaves forming a nest in which humus 
collects; the roots ramify in this and obtain food and water. A. rhi- 
zophyllum Kunze is the walking fern, so-called because the leaf-tips 
when they touch the soil bud into new individuals, and thus the plant 
spreads to some distance. 
Astelia Banks et Soland. Liliaceae (vi). 9 sp. Polynes. Dioecious. 
Aster Tourn. Compositae (ill). 200 sp. Am., As., Afr., Eur. 2 sp. 
on the coast of Brit. (Michaelmas daisy), both, like so many shore 
plants (p. 169), somewhat fleshy. The China-aster of gardens (A. 
chinensis L.) is a sp. of Callistephus. 
Asterales. The 2nd cohort of Dicotyledons (Gamopet.) in the classifi- 
cation of Bentham and Hooker. See p. 134. 
Astilbe Buch.-Ham. Saxifragaceae (1). 6 sp. As., N. Am. 
Astragalus Tourn. Leguminosae (in. 6). Abt. 1200 sp. cosmop., 
except Austr. 3 in Brit, (milk- vetch). The bulk are N. temp, plants 
living on steppes, prairies &c. and are more or less xerophytic. A 
great number are thorny ; the thorns commonly form by the stiffening 
of the petiole or midrib of the leaf when the blade falls off. A. gum - 
mifer Labill. and others yield gum-tragacanth, obtained by wounding 
the stem and allowing the resin to exude and harden. 
Astrantia (Tourn.) Linn. Umbelliferae (3). 5 sp. Eur., As. 
Astrocarpus Neck. Resedaceae. 1 variable sp. S. W. Eur. 
Astrocaryum G. F. W. Mey. Palmae (iv. 7). 29 sp. trop. Am. 
Asystasia Blume. Acanthaceae (iv. b). 20 sp. Old World trop. 
Atalantia Correa. Rutaceae (x). 12 sp. trop. As., China, Austr. 
Athamanta Linn. Umbelliferae (6). 3 sp. Eur., W. As. 
Athanasia Linn. Compositae (vn). 40 sp. S. Afr. 
Athrotaxis D. Don. Coniferae (Arauc. 1 c ; see C. for genus charac- 
ters). 4 sp. Tasm. 
Athyrium Roth. = Asplenium Linn. 
Atractylis Linn. Compositae (xi). 15 sp. Medit. to Japan. 
Atragene Linn. = Clematis Linn. 
Atriplex (Tourn.) Linn. Chenopodiaceae (4). 120 sp. temp, and sub- 
trop. 6 in Brit, (orache). Firs, unisexual, naked or with perianth. 
Atropa Linn. Solanaceae (11). 2 sp. Eur., Medit., As. A. Belladonna 
L. is the deadly nightshade. It contains the alkaloid atropin, the 
basis of the drug belladonna used in medicine. 
Attalea H. B. et K. Palmae (iv. 7). 23 sp. S. Am. A. funifera Mart, 
yields some of the Piassaba fibre of commerce. 
Aubrietia Adans. Cruciferae (iv. 14). 12 sp. Medit. 
Aucuba Thunb. Cornaceae. 3 sp. Himal. to Japan. A. japonica 
Thunb. is the Japan laurel of our shrubberies. It is dioecious. 
Augusta Leandr. = Stifftia Mikan. 
Avellinia Pari. Gramineae (x). 1 sp. Medit. 
Avena Linn. Gramineae (ix). 50 sp. temp. 2 in Brit, (oat-grass). A . 
