XXVri. ZYGOPHYLLK^. 171 



Seeds exalbuminous. 

 Leaves pinnate. Petals 5, flat. Pi'nitot 5 hard, indehisoent, usually prickly 

 or tuberculate oooci . . . . . . ... ... 1. Tribuluk. 



Leaves simple. Petals H, oonoave. Fruit a drupe with ahaid 1-seeded nut 2. Niteaeia. 

 Seeds albuminous 

 Leaves with 2 leafletsor lobos. Petals ior j, flat. Fruit a i or5-angled or 



winged capsule ... . . ... . . . .... 3. ZvooPHyLLUM. 



1. TRIBULUS, Linn. 



(From tfibo, to tear ; referring to the prickly fruits.) 



(Tribulopis, E. Br.) 



Sepals 5, rarely 6. Petals as many, flat. Disk annular, 10-lobed or sinuate, 

 with a gland at tiie base of each of the inner stamens, alternating with the petals. 

 Stamens twice as many as petals, the filaments filiform, without appendages. 

 Ovary of 5 or sometimes more cells, with 1 or 2 to 6 superposed ovules in each 

 cell. Fruit separating into as many cocci as carpels, hard, indehiscent, and 

 each usually bearing 2 or more prickles or tubercles. — Herbs, usually prostrate 

 or divaricate and hairy. Leaves abruptly pinnate, opposite, with one of each pair 

 smaller than the other, or sometimes abortive or all alternate. Stipules small, 

 lanceolate, or falcate. Pedicels solitary in the axil of the smaller leaf of each 

 pair, or opposed to the leaf when alternate. Flowers white or yellow. 



The genus is dispersed over the greater part of the tropical and warm regions of the globe, 

 extending into Europe and N. America. Of the Queensland species, one is abundant in Asia, 

 Africa, and S. Europe, another is most common in tropical America, less so in Asia and Africa, 

 and the others are all endemic— Bent/j. 



Leaves, at least the upper ones, opposite. Glands of the disk not very 

 prominent. Ovules 2 or more in each cell. (Tribulus proper). 

 Cocci rounded at the back, without angular or winged edges. 

 Cocci with 2 or 4 prickles, rarely minute or deficient. 

 Leaves almost all opposite. Ovules 3 or 4 in each cell. 

 Annual. Flowers small. Petals about Jin. . 1. T. terrestris. 



Perennial. Flowers large. Petals about Jin. . . . 2. T. cistoides. 



Flowers large. 



Cocci 2 maturing, each 7 lines diameter, silky . . . . . . 3. T. occidentalis. 



Cocci covered with numerous nearly equal prickles . . ... 4. T. hystrix. 



Leaves (except T. minutus) all alternate. Glands of the disk prominent. 

 Ovules solitary. Fruit pyramidal, the cocci with 2 or 4 tubercles or 

 small prickles below the middle. (Tribulopis, R. Br.) 

 Leaflets 2 pairs, the lowest much smaller. Perfect stamens usually 5 5. T. pentandrus. 



Leaflets about 3 pairs, ovate, or lanceolate, the lowest distant from the 



stem. Anthers 10, nearly similar. Flowers small . . . . 6. T. Solandri. 



Leaflets 4 to 6 pairs, linear. Anthers 10, similar. Flowers large ... 7. T. anriustifolius. 

 Leaflets 2 or 3 pairs, linear. Flowers small, 5 perfect. Anthers 5, sterile. 8. T. lejjtophyllus. 

 Leaflets 3 to 6 pairs, small, ovate or lanceolate. Leaves mostly opposite. 



Anthers 10, similar. Flowers very small , 9. T. miimtux. 



1. T. terrestris (from its prostrate habit), Linn.; DC. Prod. i. 703 ; Benth. 

 Fl. Austr. i. 288. Cat's-head, or Catrops. A prostrate annual or biennial, more 

 or less hirsute or silky-hairy, especially the young shoots, the stems extending 

 often to 1 or 2ft. Leaves opposite, unequal ; leaflets of the larger one usually 5 

 to 7 pairs, obliquely oblong, 8 to 5 lines long. Pedicels shorter than the opposite 

 larger leaf. Flowers small, the sepals rarely attaining 2 lines and often much 

 less, the petals rather longer, but very rarely nearly twice as long. Anthers 10, 

 all small and perfect. Ovules 3 or 1 in each cell. Cocci 5, hard, 2 to 3 lines 

 long, glabrous or hairy, rounded on the back, with 2 marginal, divaricate, 

 horizontal, subulate or conical prickles about half-way up, and often 2 smaller 

 reflexed ones lower down, the rest of the surface usually tuberculate or shortly 



