OXALIDACEAE 401 



OXALIDACEAE. Oxalis Family 



Ours low lierbs with sour juice. Leaves palmately 3-foliolate, alternate or the 

 basal opposite. Flowers borne in peduneled cymes or solitary, complete, regular, 

 symmetrical, 5-merous. Ovary superior, 5-celled; styles 5, distinct. Fruit a 

 loculicidal capsule. — Genera 7 and species about 350, all continents, some in 

 temperate regions but chieflj^ in the tropics. 



Bibliog. — Trelease, W., Oxalideae [of N. Am.], (Mem. Bost. Soc. Nat. Hist. 4:86-98, — 

 1888) ; Small, J. K,, Oxalidaceae in N. Am. Fl. 25:25-58 (1907). 



1. OXALIS L. Wood Sorrel 



Leaflets obcordate, closing and drooping at night. Peduncles axillary, 1 to 

 several-flowered. Sepals imbricated. Stamens 10 in two sets of 5 each, the longer 

 set alternate with the petals ; filaments somewhat dilated and united at base. Glands 

 none. Capsule membranous, 5-celled, more or less 5-lobed, the cells opening on 

 the dorsal sutures through which the seeds are explosively ejected, the valves re- 

 maining attached to the axis by the partitions. Seeds 2 to several in each cell, trans- 

 versely, regularly and sharpl}^ lineate. — Species about 300, all continents, chiefly 

 in subtropical regions. (Greek oxus, sour, the juice containing oxalic acid.) 



Leaves alternate on the stem ; flowers yellow. 



Filaments glabrous; leaves with hairy stipules; flowers homomorphic (styles and stamens of 



one form) 1. 0. corniculaia. 



Filaments pubescent ; leaves without stipules, the petioles merely scarious-margined at base ; 

 flowers trimorphic (styles and stamens reciprocally of three forms). .2. 0. sulcsdorfii. 

 Leaves all basal ; flowers pink, white or rose-color. 



Scapes commonly 1-flowered; petals 9 to 12 lines long 3. 0. oregana. 



Scapes commonly 3 to 6-flowered; petals 3 to 6 lines long 4. 0. trilliifolia. 



1. 0. corniculata L. Yellow Sorrel. Stems slender, several to many from 

 the crown of a tap-root, ascending, 3 to 6 inches high, or decumbent and often root- 

 ing at the nodes, 3 to 12 inches long ; herbage villous, sometimes scantily so ; leaflets 

 3 to 6 lines long, on slender petioles with small villous stipules ; peduncles axillary, 

 elongated, bearing 2 or 3 flowers; petals yellow; styles longer than or equaling the 

 longer stamens ; capsules linear, 6 to 8 lines long, many-seeded. 



Moist valleys, dry hillslopes and canons, 10 to 2000 feet : along the coast from 

 Del Norte Co. to San Diego Co., rarely in the interior. More or less cosmopolitan, 

 especially in the tropics. Apr.-Oct. 



Biol. note. — The plant soon develops a stout perennial taproot from the crown of which many 

 stems are usually produced. If the stems are trailing or decumbent, under favorable conditions 

 they may root at the nodes and thus become stolons. In general habit and in morphologic detail 

 our plants throughout the coastal region are alike ; they represent one unit. Pedicels may be erect, 

 spreading or deflexed, even on one individual. Capsules may be a little longer or very much 

 shorter than the pedicels, even on one individual. The filaments are united for about one-half 

 their length, although the proportion varies insensibly. The hairiness is inconstant. The stipules 

 do not differ. While often a weed in lawns or gardens, it is frequently found in situations where 

 we regard it as a native plant. All the stations cited below, save Santa Cruz, are thought to repre- 

 sent indigenous habitats. We exclude Oxalis wrightii Gray from California, as does J. K. Small 

 (N. Am. Fl. 25 :54), but on wholly different grounds. 



Locs. — La Junta near Jamul, Newlon 344; La Mesa, w. San Diego Co., Jepson 6680; Pala, 

 Parish 4397; Oceanside, Parish 4l4:4:2; Fish Caiion, San Gabriel Mts., Peirson 2126; Sycamore 

 Canon, Santa Lucia Mts., Jepson 9161 ; Santa Cruz Isl., T. Brandegee; Lucia, Santa Lucia Mts., 

 Jepson 1669; Capitola, Santa Cruz Co., Pendleton; San Francisco, about 1791, Menzies (Cal. 

 Hist. Soc. Quar. 2:289); Potter Valley, Mendocino Co., Nettie Purpus; Eureka, Tracy 5119; 

 Kequa, Del Norte Co., Davy 5903b ; Butte Creek, e. of Chico, B. M. Austin 204. 



Var. atropurpurea Planch. Stems and foliage deep red-purple. — Native of Europe, some- 

 times used in gardens for bedding and thus an escape : Berkeley ; San Bernardino. 



Eefs. — Oxalis corniculata L. Sp. PI. 435 (1753), type from Italy; Jepson, Fl. W. Mid, Cal. 

 245 (1901), ed. 2, 241 (1911), Man. 588 (1925) ; Parish, Muhl. 3:4 (1907). 0. wrightii Jepson, 

 Man. 588 (1925) and other Cal. authors, not Gray. Xanthoxalis calif ornica Abrams, Bull. Torr. 



