100 
PLANTS INDIGENOUS TO 
[Zygophylle®. 
petals obovate-cuneate, not much long’er than the calyx, or extending* to twice its length; style frequently 
longer than the stigma 5 carpels wingless^ depressed) with two dorsal tliowis, downy and often tuberculated 
at the back, generally three-celled. 
On the arid plains near the junction of the Murrumbidgee with the Murray River, where it is accom¬ 
panied by Euphorbia Chamsesyce, Frankenia lsevis, Cressa Cretica and a few other plants, extending from 
South Europe through Asia and the hotter parts of Australia to the northern boundaries of our colony. In 
South Australia north of Lake Torrens; in Western Australia within the settlements, according to J. Hooker; 
not rare within the tropics of Australia, Asia and Africa, rarer in America. 
Root annual, perhaps occasionally also bi- or triennial, cylindrical, producing some capillary-filiform 
fibres. Stems §-2 feet long, nearly terete, streaked, simple or branched, densely covered with short grey 
ascending or occasionally spreading downs, and besides beset with scattered longer hair, according to Kralick 
sometimes quite smooth. Leaves sliort-petiolate, alternately smaller, if—2 inches long'. Stipules from a broad 
base ovate- or falcate-lanceolate, sometimes linear-lanceolate or even linear, 1-4 lines long. Leaflets l |-6 
lines long, f -3 rarely 4 lines broad, oftener blunt than acute, above soon glabrous or rarely retaining its 
pubescence in age, beneath and at the margin, as well as the rachis, pedicels and sepals, covered with an 
indument similar to that of the stem and branches, the upper and lower ones gradually diminishing in size. 
Pedicels slender-filiform, 4-14 lines long. Sepals measuring in length 1J-3 lines. Petals smooth, connected 
at the base with the opposite stamens. Filaments yellow, glabrous, generally 1J-2 lines long. Anthers J-J 
line long, ovate, sometimes verging' into a more round or oblong form. Pollen-grains globose, slightly 
rough. Style green, smooth, sometimes exceedingly short, sometimes more or less elongated, capable of 
extending to the length of three lines, at last dropping. Rays of the stigma yellowish, about J line Ion*. 
Ovary clothed with appressed white hair. Carpels connected into a starry fruit, 2—5 lines long, glabrous and 
lacunose at the commissural side, about the middle of the lateral edges armed on both sides with a stout 
subulate straight slightly dovm-bent thorn, which is generally less than 3 lines long, provided besides not 
rarely at the base with two shorter thorns, which point downward, rarely thornless, covered at the back with 
downs and with either tubercles or small pungent points, which again are terminated by a short bristle. 
Seeds placed oblique-horizontally, 1—2 lines long, pointed at the liilum, ovate-cuneate. Testa pale-grey, 
almost opaque. 
Specimens of this species, gathered in South Europe, Ceylon, Bengal, China, Timor and the Islands of 
Torres Straits, and compared on this occasion, differ in no essential note from the Australian plant, which 
moreover has been identified by J. Hooker with T. cistoides, and accords with the figures quoted. An allied 
species, found in the deserts around Lake Torrens, T. Hystrix (R. Br. in Sturt’s Exped. ii. App. 69; T. 
lanatus, Walp. Annal. ii. 243), differs principally in copiously" thorny fruit. To Tribulus terrestris belong 
evidently many of the plants hitherto acknowledged as distinct congeners. 
ZYGOPHYLLUM. 
IAnncy Gen . Plant . 530. 
Sepals 4 or 5, persistent or deciduous. Petals 4 or 5, unguiculate. Stamens twice as many as 
petals and as sepals, opposite to them, all fertile. Filaments free. Anthers two-celled, versatile, 
with introrse longitudinal dehiscence. Hypogynous disk annular, sinuate. Ovary 4-5- rarely 2-3- 
celled. Ovules 2 or more, sometimes numerous in each cell, suspended in a double row from the 
central angle, anatropal. Style setaceous or subulate, furrowed. Stigma very small, furrowed or 
cleft. Capsule 4-5- rarely 2—3-celled, 'with loculicidal rarely with septicidal dehiscence. Column 
persistent. Seeds 1 , 2 , or several in each cell, pendent. Hilum situate below the apex of the seed. 
Exterior i/ntegu/ment of the seed when moistened mucilaginous; interior one subcoriaceous or 
