376 ARCTIUM, ASCLEPIAS. 



171. ARCTIUM. 49. 54. 



lapf'pa (burdock. O. r. Au. 4). cauline leaves heart-form, petioled, toothed 

 flowers panicled, globose : calyx smooth. 



103. ARENARIA. 22. 82. 



1 Leaves oblong. 



laterifior"a (sand-wort. O. w. J. 4). stem filiform, simple: leaves ovate, obtuse, 

 Bub-triple-nerved : peduncles lateral, solitary, elongated, 2 cleft; oneped.cel 

 middle-bracted ; corolla longer than the calyx. 610 i. 



181. ARETHUSA. 7. 21. 



bulbo'sa (arethusa. O. r. J. 4) leafless : root globose; scape sheathed, 1 flow- 

 ered ; calyx with the superior divisions incurved ; lip sub-crenulate, Flowers 

 large, sweet-scented. Damp. 



186. ARISTOLOCHIA. 11. 23. 



serpenta'ria (O. p. J. 4). leaves heart-form, oblong, acuminate ; stem zigzag, 

 ascending ; peduncles radical ; lips of the corolla lanceolate. (The Virginia 

 snake-root). There is a variety with very long, narrow leaves. 

 111. ARMENIACA. 36. 92. 



J-}.rtic. 



vulga'ris (apricot > ). leaves sub-cordate ; stipules palmate. Var.precox (early 

 apricot), fruit small, yellow. Var. persicoides (peach apricot), fruit sub- 

 compressed. 



115. ARONIA. 36. 92. 



botri/a'pium (shad-bush, june-berry. O. w. Ap. ^ ). leaves oblong-oval, cuspi- 

 date, glabrous when mature (when first expanded lanceolate and downy) ; 

 flowers racemed ; petals linear ; germs pubescent ; segments of the calyx 

 glabrous. 



172. ARTEMISIA. 49. 55. 



Exotic. 



pon"tica (roman artemisia). leaves downy beneath ; cauline ones bipinnate ; 

 leafets linear ; branches simple ; flowers roundish, pedunclcd, nodding. 



absynth"ium (wormwood. 4). stem branching, panicled ; leaves hoary ; radical 

 ones triply pinnatifid ; divisions lanceolate, toothed, obtuse ; cauline ones 2 

 pinnatifid or pinnatifid ; divisions lanceolate, acutish ; floral ones undivi- 

 ded, lanceolate. Naturalized in the most mountain districts of New Ki in- 

 land. 



abrota'nttm (southern-wood. 4. & * ). stem straight ; lower leaves bipinnate ; 

 upper ones hair form, pinnate ; calyx pubescent, hemispheric 

 19-12. ARUM. 2. 7. 



triphyl"lum (indian turnip, wild turnip, wake robin. O. p. g. & w. M. 4). sub- 

 caulescent; leaves ternate ; leafets ovate, acuminate, spadix club-form; 

 spatha ovate, acuminate, peduncled with the lamina as long as the spadix. 

 One variety, virens, has a green spatha ; another, atropurpureum, has a dark- 

 purple spatha ; another, album, has a white spatha. 1 3 f. 



32. ARUNDO. 4. 10. 



canaden"sif (E. Au. 4). panicle oblong, loose ; glumes scabrous, pubescent, as 

 long as the corolla ; corolla awned on the back ; hairs at the base e<j nai- 

 ling the valves : culm and leaves smooth. 34 f 



1812. ASARUM. 11. 23. 



canaden"se (white snake-root, wild ginger. O. g-p. M. 4), leaves broad-reniform, 

 in pairs ; calyx woolly, deeply 3 parted ; the segments sub-lanceolate, 

 reflexed. S. 



185. ASCLEPIAS. 30. 47. 



1. Leaves apposite. 



xyri'aca (common milkweed, O. w-p. Ju. 4), stem very simple ; leaves lanceo- 

 late-oblong, gradually acute, downy beneath ; umbels sub-nodding, downy, 

 3 to five feet high ; flowers in large, close clusters, sweet-scented pollinia 

 are fly-traps. 35 f. S. 



incama'ta (O. r. Ju 4), stem erect, branching above, downy ; leaves lanceolate, 

 sub-downy both sides ; umbels mostly double at their origin ; the little horn 

 of the nectary exsert. A variety pulrhra is more hairy. Var. glabra, almost 

 glabrous. Var. alba, has white flowers. Damp. 3f S, 



