AR THR O PODIUM 
249 
Ovary 4 — 6-loc. ; ovules 00 in each loc., anatropous, horizontal or 
pendulous. Capsule. Embryo small in rich endosperm. The A. 
are difficult to place in the natural system. They have been put near 
Dioscoreaceae, though they are not monocotyledonous. Benth. -Hooker 
place them in Multiovulatae Terrestres, Eichler (Warming) in Hyste- 
rophyta. Chief genera: Asarum, Aristolochia. 
Aristolochiales. The 8th cohort of Dicot. Archichl. (see p. 127). 
Aristotelia L’Herit. Elaeocarpaceae. 10 sp. S. temp. 
ArmeriaLinn. Plumbaginaceae. sosp.N. temp, and andine. A . vulgaris 
Willd., the thrift or sea pink, is common on the coast of Brit, and in 
high mountain regions of Scotland (see p. 187). The primary root is 
perennial; each year’s shoot dies down all but a short piece, on which 
the following year’s shoot arises as an axillary branch. The infl. 
is a capitulum of cincinni, surrounded by a whorl of bracts, the 
outer ones forming a sheath round the top of the peduncle. After 
fertilisation the calyx becomes a membranous funnel-like organ aiding 
seed-distribution by wind. 
Arnebia Forsk. Boraginaceae (iv. 4). 12 sp. Medit. , Himal. .Some 
have black spots on the corolla, which fade out as it grows older (see 
order, and cf. Diervilla, Fumaria &c.). 
Arnica Rupp. Compositae (vm). 18 sp. N. temp, and arctic. 
Arnoseris Gaertn. Compositae (xm). 1 sp., A . pusilla Gaertn., in 
Eur. (incl. Brit.). The bases of the involucral bracts enclose the ripe 
fruits (cf. Rhagadiolus). 
Aroideae (Benth. -Hook. ) = Araceae. 
Arrhenatherum Beauv. Gramineae (ix). 3 sp. Eur., Medit. A.avena- 
ceum Beauv., the false oat-grass or French rye-grass, in Brit. 
Artabotrys R. Br. Anonaceae (6). 23 sp. Old World trop. They are 
cultivated for their sweetly scented firs, and edible fruit. They 
usually climb by aid of recurved hooks, which are modified inflo- 
rescence-axes. 
Artanthe Miq. = Piper Linn, (usually same spec, names; A . elongata 
Miq. =P. angustifolium). 
Artemisia Linn. Compositae (vn). 200 sp. N. Hemisph., very 
common on the arid soil of the western U.S., the Steppes &c. 
4 in Brit, (wormwood). Fir. -heads small, inconspicuous, and wind 
fertilised (cf. Poterium, Rheum and Rumex, Plantago, Thalictrum, 
&c.). In A. vulgaris L. the marginal florets are ? , the rest g . The 
head is pendulous ; the anther-tube projects beyond the corolla, so 
that the dry powdery pollen is exposed to the wind. On the tips of 
the anthers are long bristles which together form a temporary pollen- 
holder. Afterwards the style emerges and the large hairy stigmas 
spread out. The flr. affords a very interesting case of reacquisition of 
a character not found in most higher flowering plants. 
Arthraxon Beauv. Gramineae (11). 9 sp. trop. Old World. 
Arthropodium R. Br. Liliaceae (hi). 8 sp. Austr., N.Z., New Caled. 
