666 OXALIDACEAE 



1. Monoxahs dichondrae folia (A. Gray) Small. Foliage closely pubescent with 

 short gray hairs. Stems woody below, the branches tufted, more or less spreading or 

 decumbent, 1-3 dm. long : leaves rather numerous : leaflet 1, the blade suborbicular, 

 inclined to obovate, oblong or ovate, 1-3 cm. long, retuse and somewhat apiculate at the 

 apex, undulate, ciliate, cordate at the base: pedicels 0.6-1 cm. long, with 2 bracts like the 

 stipules, enlarged upward : sepals lanceolate or triangular-lanceolate, 5-10 mm. long, acute 

 or acuminate, auriculate-cordate at the base : petals about twice as long as the sepals, erose- 

 undulate at the apex, the claw about as long as the blade : capsules oblong or ovoid- 

 oblong, 8-10 mm. long, about as long as the sepals : seeds about 2 mm. long, with promi- 

 nent somewhat confluent tubercles, lustrous. [Oxo/is dichondraefolia A. Gray. ] 



In dry soil, southern and southwestern Texas and adjacent Mexico. Spring to fail. 



4. LOTOXALIS Small. 



Perennial caulescent herbs, with horizontal rootstocks. Stems branched at the base, 

 the branches woody below, corymbosely branched above. Leaves alternate : petioles 

 without stipules : blades pinnately 3-foliolate : leaflets more or less oblique. Peduncles 

 axillary, topped by umbel-like cymes. Pedicels recurved before and after flowering, not 

 deflexed. Flowers perfect. Sepals 5, thin, acute, erect, imbricated. Petals yellow, much 

 longer than the sepals. Stamens 10 : longer filaments ciliate. Stigmas 2-cleft. Capsule 

 oblong-ovoid, surpassing the sepals, drooping. Seeds slightly flattened, with 5-8 longi- 

 tudinal rows of sharp tubercles. WOOD-SORREL. 



1. Lotoxalis Berlandieri (Torr. ) Small. Rootstocks woody. Foliage gray or 

 tawny-pilose. Stems branched at the base, the branches erect or ascending, 5-25 cm. long, 

 woody below, commonly branched : leaflets 3, the blades thickish, cuneate, obovate or ob- 

 long, 5-20 mm. long, unequally notched at the apex, ciliate, mostly pubescent on both 

 surfaces, rounded at the base, the lateral much smaller than the terminal : pedicels often 

 3, recurved at maturity : sepals oblong, 5-8 mm. long : petals yellow, about twice as long 

 as the sepals : longer filaments ciliate : capsules oblong-ovoid, 7-8 mm. high, depressed at 

 the apex : seeds fusiform or nearly elliptic, 1.5-2 mm. long, with sharp tooth-like tubercles 

 in longitudinal rows. [ Oxalis Berlandieri Torr. ] 



In dry or sandy soil, southern Texas and adjacent Mexico. Spring to fall. 



5. XANTHOXALIS Small. 



Annual or perennial caulescent herbs, with descending or horizontal rootsocks. Stems 

 sometimes woody at the base. Leaves alternate : stipules obsolete or appearing as narrow 

 dilations at the base of the petiole : blades palmately 3-foliolate ; leaflets broadly obcordate, 

 usually inequilateral, nearly sessile or rarely stalked, sometimes sensitive. Flowers per- 

 fect, heterogonous or homogenous. Sepals 5, narrow, imbricated. Corolla yellow, some- 

 times with a darker eye. Petals 5, surpassing the sepals, rounded or notched at the apex. 

 Stamens 10 : filaments glabrous or the longer ciliate. Capsule more or less elongated, 

 columnar or narrowed upward, angled, 5-celled. Seeds several in eacli cavity, trans- 

 versely ridged or tuberculate by broken ridges. YELLOW WOOD-SORREL. SOUR-GRASS. 



Plants with creeping elongated stems or branches. 



Sepals ciliate at the tip or only near it : longer filaments glabrous. 1. X. corniculata. 



Sepals ciliate nearly all around : longer filaments ciliate above. 2. X. Langtotitt. 



Plants with erect stems, or if branched at- the base the branches sometimes decum- 

 bent, often with horizontal rootstocks. 



Stems and petioles strigillose with decidedly appressed hairs. 

 Longer filaments ciliate above. 



Sepals 2-4 mm. long, ciliate mainly or only at the tip : corolla pale yellow, 



0.5-1.5 cm. broad. 3. X.filipes. 



Sepals 4-5 mm. long, copiously ciliate all around : corolla golden yellow, 



1.5-2.5 cm. broad. 4. X. macrantha. 



Longer filaments glabrous. 



Leaflets strigillose : sepals copiously ciliate : corolla golden yellow. 5. X. Texana. 



Leaflets glabrous or merely with a few scattered hairs : sepals sparingly 



ciliate : corolla pale or light yellow. 6. A', stricta. 



Stems and petioles villous or with loosely spreading hairs. 

 A Pedicels with erect or appressed hairs. 

 Longer filaments glabrous. 



Sepals ciliate nearly all around : leaflets bright green. 7. X. Bmhii. 



Sepals ciliate only at the apex : leaflets reddish purple. 8. X. rufa. 



Longer filaments ciliate above or throughout. 



Leaf- blades red or purple. 9. A", colored. 



Leaf-blades bright green. 



a. Sepals ciliate nearly all around: leaflets mainly less than 15 mm. broad. 



