XXXI. ZYG0PHYLLE2E (OLIVEU). 283 



1-2 or more in each cell. Fruit crustaceous or coriaceous (in the following 

 genera), often separating in as many dehiscent or indehiscent cocci as carpels, 

 sometimes spinose or winged. Seeds with or without albumen. Embryo 

 as long as the seed. Cotyledons oblong or linear; radicle straight.— 

 Shrubs or herbs, woody below, with divaricate jointed branches. Leaves 

 opposite, one of the pair usually smaller, 1-2-foliolate or pinnate, glabrous, 

 pilose or hispid, often fleshy, with interpetiolar often spinescent stipules, 

 rarely simple, alternate or fascicled (Nitraria). Flowers pedunculate, solitary 

 or geminate, apparently axillary, usually yellow white or rose. 



Leaves opposite. 

 Flowers with petals. 



Leaves abruptly pinnate. Filaments naked 1. Tribulus. 



Leaves 1-2-foliolate. Filaments with a scale at the base ... 2. Zygophyllum. 



Leaves 3-1-foliolate. Filaments naked 3. Fagonia. 



Flowers apetalous. Leaves 3-foliolate 4. Seetzema. 



Leaves alternate or fascicled, simple, spathulate or cuneate. (A 



spreading shrub.) 5. Nitraria. 



1. TBIBULTTS, Linn. ; Benth. et Hook. f. Gen. PL i. 264. 



Sepals 5, persistent or deciduous. Petals 5, spreading. Stamens 10; 

 filaments filiform, those opposite to the petals sometimes adnate at the base. 

 Ovary sessile, usually densely hirsute, 5-1 0-(-l 2-)celled. Style short ; adnate 

 lobes of the stigma as many as cells. Ovules 1-5, superimposed. Fruit of 

 5-12 indehiscent cocci (or fewer by abortion), woody or bony, spinose 

 winged or tubercled. " Seeds exalbuminous." — Ascending or prostrate, 

 branching, usually pilose or hispid herbs. Leaves opposite, one in each pair 

 smaller, abruptly pinnate, stipulate. Flowers solitary, axillary, pedunculate, 

 white or yellow. 



The species want a thorough revision. I am not satisfied with the characters given be- 

 low. It ig doubtful if any of these species are confined to the tropics of this continent. 

 Ovary 5-(4-)celled. Stigma 5-(4-)angled or lobed. 



Carpels not winged, usually spinose I. T. terrestru. 



Carpels winged, with or without spinose margins. 



Fruit pyramidal-ovoid, spinosely winged . 2. T. alatus. 



Fruit roundish or roundish-ovoid, depressed at apex, 3-4 lines 



long and broad. Wings crenulate, about 1 line broad . . . 3. T. pterocarpiix. 

 Fruit larger than in No. 3. Wings toothed, strongly nerved, 



i-i in. broad 4 - T - Ehrenbergii. 



Ovary 10-12-celled. Stigma 10-12-angled or lobed 5. T. maximus. 



1. T. terrestris, Linn. ; DC. Prod. i. 703. A spreading prostrate or 

 decumbent annual, occasionally more or less frutescent below and persisting 

 two or more years. Branches from a few inches to 2 or 3 ft. in length, pu- 

 bescent, villous or hispid. Leaves in unequal pairs, the larger l-2£ in., 

 with 5-8 pairs of oblong or linear-oblong, more or less acute, sessile or sub- 

 sessile, opposite leaflets,°oblique at the base, villous beneath, often glabres- 

 wnt above. Peduncles £-1 in., scarcely or not at all thickened in fruit. 

 Flowers usually yellow. Stigmatic lobes longer than the diameter of the 

 style (or shorter in £. cistoides). Calyx deciduous. Fruit-carpels tubercled 

 and often setose on the back and above, each carpel usually with 2 lateral 



