122 " OXALIDACEiE Oxalis. 



Order XXVI. OXALIDACE^. DC. The Wood-sorrel Tribe. 



Calyx of 5 persistent equal sepals, imbricated in aestivation. Corolla of 5 equal 

 hypogynous deciduous petals, twisted in aestivation. Stamens 10, hypogynous ; 

 the filaments broad, and somewhat united at the base. Ovary of 5 united 

 carpels placed opposite the sepals : styles distinct : stigmas capitate or pencil- 

 late. Capsule usually membranaceous, 5-lobed, 5-celled, opening by the 

 dorsal suture, 1 - several-seeded. Seeds with a loose fleshy arilliform epi- 

 dermis, which bursts elastically when ripe. Albumen between fleshy and 

 cartilaginous. Embryo straight, as long as the albumen, with a rather long 

 radicle : cotyledons broad and foliaceous. — Mostly low herbaceous plants 

 (rarely suffrutescent or arborescent), with an acid juice. Leaves alternate, 

 compound : leaflets usually obcordate. 



1. OXALIS. Linn.; Endl. gen. 6058. woOD-SORREL. 



[ From the Greek, oxys, sharp or sour ; in allusion to the strong acid taste of the plant.] 



Sepals distinct, or only united at the base. Capsule oblong or somewhat globose, membrana- 

 ceous. Seeds 1, or commonly several in each carpel: testa 5 - 10-ribbed, transversely 

 rugose. — Perennial (rarely annual) herbs ; caulescent or stemless. Leaves in all the 

 North American species trifoliolate, circinate in vernation : leaflets articulated to the petiole. 

 Stipules coherent with the base of the petiole, or wanting. 



1. Oxalis Acetosella, Linn. Common Wood-sorrel. 



Rhizoma creeping, scaly ; leaflets obcordate, puberulent ; scapes at length longer than the 

 leaves, one-flowered, with 2 bracteoles above the middle ; petals oblong-obovaie (white, with 

 red veins) ; styles and longer stamens of equal length, longer than the sepals. — Eng. hot. 

 t. 762; Michx.jl. 2. p. 38; Pursh,fl. l.p. 322; Torr.Jl. \.p. 461 ; Bigel.fl. Bost.p. 257; 

 DC. prodr. 1. p. 700 ; Hook. fl. Bar. -Am. 1. p. 118 (partly) ; Torr. ^ Gr. fl. N. Am. 1. 

 p. 211. 0. Americana, Bigel. in DC. I. c. ; Zucc. man. Oxal.p, 35. 



Rhizoma scaly and somewhat toothed with the persistent and somewhat fleshy bases of the 

 petioles. Petioles 2-3 inches long : leaflets broadly obcordate. Scape 3-5 inches long. 

 Flower about three-quarters of an inch in diameter, drooping. Sepals villous-ciliate, with 

 reddish hairs. Petals often obliquely emarginate, yellow at the base. Stigmas 2-lobed. 

 Cells of the capsule about 2-seedcd. 



In woods ; often on high mountains; west and north of Catskill. June. — The American 

 plant is identical with the European, except that the petals of the former are for the most 



