100 American Midland Naturalist Monograph No. 7 



spicuously ciliate; plants annual; diy soil, local. July-Sept. 

 L. sulcatum Riddell 



38. Oxalidaceae Lindl. — Wood-sorrel Family 



1. Oxalis L. 

 1. Flowers purple (rarely white), 14-20 mm long; plants scapose, 

 with a thick bulb-like or scaly rhizome; woods, common. Apr.- 



June. Violet Wood-sorrel O. violacea L. 



1. Flowers yellow; stems leafy; rhizomes slender. 



2. Stems creeping, rooting at the nodes, the pubescence of spread- 

 ing hairs; pedicels strigillose; a weed in greenhouses and 

 gardens; native of Eur. Creeping Wood-sorrel. [O. re pens 



Thunb.] O. corniciilata L. 



2- Stems erect, or decumbent at the base. 



3. Pedicels and stems strigillose; capsules finely grayish- 

 pubescent, abruptly pointed, the styles 1-2 mm long; fruit- 

 ing pedicels becoming deflexed but the capsules erect; 

 common in fields, along roads, or in open woods. May- 

 Sept. Common Yellow Wood-sorrel [O. stricta of auth., 



not L.] O. dillenii Jacq. 



3. Pedicels and stems with spreading hairs, or the latter nearly 

 glabrous; capsules sparsely glandular-pilose to nearly 

 glabrous, gradually pointed, the styles 2-3 mm long; fruit- 

 ing pedicels ascending or divergent. 

 4. Petals 3-10 mm long; seeds about 1.5 mm long, with nearly 

 continuous ridges; occasional plants have red foliage; 

 roadsides and open woods, common. June-Nov. 

 Upright Wood-sorrel. [O. cymosa Small; O. europaea 



Jord.] O. stricta L. 



4. Petals 12-16 mm long; capsules 6-10 mm long; seeds 2 

 mm long, the ridges discontinuous; woods, rare; near 

 the Wabash R., Mt. Carmel, Schneck O. grandis Small 



39. Limnanthaceae Lindl. — Limnanthes Family 



1. Floerkea Willd. — False Mennaid 

 F. proserpinacoides Willd. Moist ground in woods, locally abun- 

 dant; extending southward to Edwards and Crawford counties. Apr.- 

 June. 



40. Zygophyllaceae Lindl. — Caltrop Family 

 1. Flowers (in our species) 1-1.5 cm in diameter; carpels five, several-ov-uled, 



at maturity bearing 2-4 prickles 1. Tribulus 



1. Flowers (in our species) 2-2.5 cm in diameter; carpels ten, 1-ovuled, 

 tuberculate, not spiny 2. Kallstroemia 



1. Tribulus L. — Caltrop. Puncture-weed 

 T. terrestris L. Waste places and sandy soil, occasional; nat. from 

 southern Eur. June-Sept. 



