284 XXXT. ZYGOPHYLLE^) (OLIVEll). [TribulllS. 



divergent, straight, acute spines inserted above the middle and 2 shorter 

 spines near the base directed downwards ; the spines rarely reduced to mere 

 tubercles. —T. albus, Poir. ; DC. Prod. i. 703. T. humifusus, Schum. et 

 Thonn. Guin. PI. 215. T. Kolschyanns, Boiss. Diag. Ser. 2. i. 111. T. 

 mollis, Ehrenb. in Schweinf. PL ;3£thiop. 29. T. excrucians, Wawr. et Peyr. 

 Sert. Beng. 17. 



Var. /3. cistoides (T. cistoides, Linn. ; DC. Prod. i. 703). Petals f-1 \ in. long. Stig- 

 matic lobes not longer than the diameter of the style. 



A widely-spread and very variable weed, common throughout tropical Africa as, indeed, 

 through the tropics of the Old World, extending into South Europe and Australia. The 

 variety cistoides is most frequent in tropical America. In Africa I have only seen it from 

 Guinea {Brunner), Angola {Dr. Wehoitsch), and Mozambique. 



2. T. alatus, Delile ; DC. Prod. i. 703. A procumbent or ascending, 

 hispid-villous annual, very similar to T. terrestris, the general description of 

 which will apply, differing principally in the fruit which is broadly pyramidal- 

 ovoid, as broad as long, somewhat pointed ; the spines more or less confluent 

 into prominent vertical, hard or coriaceous wings on each side, the back of 

 the carpels usually rugose, pilose. Calyx persistent or deciduous. — T. longi- 

 petalus, Viv. Dec. 10 {fide Boiss. Fl. Orient, i. 902). 



Nile Land. Nubia {Schweinf. et Asch. JSnum.). 

 From North Africa eastward to India. 



3. T. ptero carpus, Ehrenb. in Walp. Ann. iv. 404, and Schweinf. Fl. 

 Mthiop. i. 29. Habit and general aspect that of T. terrestris. Branches 

 somewhat hispid-pilose, with unequal, spreading short hairs. Fruit reflexed 

 or patent on peduncles of \ in. or shorter, roundish or ovate-rotuudate in cir- 

 cumscription, 3-4 lines long and broad. Carpels pilose on the back ; margins 

 with a continuous, crenulate, vertical wing, slightly exceeding the apex of 

 the fruit, about 1 line broad ; nerves of wing inconspicuous, parallel. — (An 

 T. macropterus, Boiss. Diag. Ser. 1. i. 61 ? An etiam T. megistopterus, 

 Kralik. in Ann. Sc. Nat. Ser. 3. xi. 32? cf. Schweinf. Fl. iEthiop. i. 24^). 



Nile Land. Dongola, Ehrenberg ! 



4. T. Ehrenbergii, Asch. in Schweinf. Fl. ^Ethiop. i. 249. Densely 

 villous. Leaves 1\ in., 6-jugnte. Peduncles erect, \ in. or less. Fruit 

 large, 4-angled, shortly and densely pubescent or pilose. Carpels broadly 

 winged ; wings rigid, \-\ in. long, \-\ in. broad, strongly reticulate below, 

 irregularly and deeply toothed.— T. crislatus, Ehrenb. in Walp. Ann. iv. 

 404, and Schweinf. Fl. Mthiop. i. 29. 



Nile Land. Dongola, Ehrenberg ! 



5. T. maximus, Torr. et Gray, Fl. North Amer. i. 213, var. minor. 

 A spreading herb or suffrutescent, hispid-pilose or pubescent. Larger leaf of 

 each pair with 3-4 pairs of elliptic-oblong, subacute or obtuse, mucronate 

 leaflets, glabrate above. Peduncles shorter than or nearly equalling the 

 leaves, at length slightly thickened upwards. Flowers small, white. Ovary 

 pubescent, pyramidal, 10-celled. Calyx persistent.— Kallslrcema minor, 



