912 ZYGOPHYLLACEyE. Tribuleje. 



species of Nuttall, O. pumila from Oregon, and O. pilosa from California, we 

 should also refer to O. corniculata.* 



6. O. stricta (Linn.): [root annual; ] stem erect, leafy; peduncles umbel- 

 liferous, 2-6-flowered, about the length of the leaves; leaflets obcordate; 

 petals [yellow] entire ; styles the length of the inner stamens. DC. I. c. ; 

 Jacq. Oxal. t. 4; Fl. Dan. t. 873 ; Michx. I. c. ; Pursh, Ji. 1. p. 322; Ell. 

 sk. 1. p. 526; Jlook. I. c. O. Dillenii, Willd. sp. 2. p. 799. O. recurva, Ell. 

 I.e. 



In cultivated grounds, Canada ! to Louisiana ! Common west of the Rocky 

 Mountains, Douglas ex Hook. — Variable in size, mode of growth, and in the 

 juumber and magnitude of the flowers. Flowers throughout the summer. 



Order XXXII. ZYGOPHYLLACE^. B. Br. 



Flowers perfect, regnlar. Sepals 4-5 : aestivation usually convo- 

 lute. Petals as many as sepafs, and alternate with them, unguiculate, 

 at first very short and scale-like (in aestivation mostly convolute), at 

 length rather longer than the sepals. Stamens twice as many as the 

 petals, hypogynous : filaments distinct, dilated at the base, sometimes 

 placed on the back of a small scale : anthers fixed near their middle, 

 introrse. Ovary composed of 4-5 united carpels placed opposite the 

 petals, surrounded at the base with 5 scales or glands, or by a sinuate 

 disk : ovules in each carpel 2 or more, attached to the inner angle, 

 pendulous or rarely erect : styles and stigmas united. Fruit capsular 

 or rarely fleshy, 4-5-coccous (or 10-coccous by the carpels being spuri- 

 ously 'i-celied), indehiscent, the cocci at length separating, or loculi- 

 cidal ; the sarcocarp not separable from the endocarp. Seeds usually 

 fewer than the ovules, anatropous : albumen cartilaginous or horny, 

 rarely none. Embryo green : cotyledons foliaceous. — Herbs, shrubs, 

 or trees ; with the branches mostly articulated at the nodes. Leaves 

 opposite, stipulate, not dotted, rarely simple. 



Tribe L TRIBULE^E. Ad. Jtiss. 



Stigma 5- or 10-ribbed, broader than the short style. Carpels inde- 

 hiscent, externally tuberculate or prickly, internally divided by ob- 



• The characters given by Mr. Nutlall are subjoined; 



"0.pum.ila: perennial, more or less hairy; umbelliferous 2-flowered peduncles 

 scarcely longer than the petioles; leaflets obcordate, deeply emarginated ; sepals ob- 

 long-lanceolate; styles shorter than the inner stamens; capsules nearly smooth, 

 about twice the length of the calyx. — Forests of the Rocky Mountains and Oregon. 

 Root at length woody ; branches decumbent. Capsules unusually short." J^^utt. 



" O. pilosa : perennial, densely hirsute, decumbent ; peduncles about 1-flowered 



{1-3 in specimen], longer than the petioles; leaflets obcordate, almost bifid; sepals 

 anceolate ; styles short; capsules very hairy, more than 3 times the length of the 

 calyx. — Woods around St. Barbara, California. A small very hairy species, with 

 ytliow flowers: nearly allied to the preceding." NuU. 



