424 



NATURAL HISTORY OF PLANTS. 



Zygophyllum (Ttmperd) 

 fabagifolium. 



frutescent plant, with fluted branches, often prismatic, the leaves 

 opposite, compound-pinnate, with two opposite unsymmetrical 

 folioles, beyond which the rachis is often prolonged under the form of 

 a small tongue, and with a petiole articulate at the base, accompanied 

 by two lateral stipules. The flowers are situated in the vicinity of 

 the axil of the stipules belonging to two opposite leaves, and at the 

 same time almost at the bottom of the angle formed by the diver- 

 gence of the axillary branches of these two leaves. 1 They are either 

 solitary, or more frequently geminate, one of the two being } r ounger 

 than the other, upon the side of which it is placed. 2 



In some species of this genus, distinguished under the name of 

 Agrophylhtwi? the folioles are rounded instead of being flattened, as 



in the preceding ; the dehiscence of the fruit is 

 septicidal, and the ovules present slight differences 

 in their form. 4 In others again, inhabiting Aus- 

 tralia, and which have been made into the genus 

 R(cpera h (fig. 503), the fruit is sometimes loculi- 

 cidal and sometimes septicidal, and the staminal 

 filaments have no interior appendage. There are, 

 moreover, other characters which may vaiy in the 

 genus Zygophyllum — viz., the number of folioles 

 to each leaf, which may be reduced to one ; the 

 consistence of the stipules, which may become spinescent ; the 

 floral type, which is sometimes quaternate ; the form of the disk, 

 which is rarely cupuliform ; and the number of the ovules, which 

 may be reduced to two in each cell. Thus Sarcozygiunf consists 

 of species of Zygojjhylltan, with winged fruits, 7 the flowers of 

 which are tetramerous, and the leaves opposite and bifoliolate, cha- 

 racters quite insufficient to found a genus; and Z. port 'ulacoides* from 

 Bokhara, distinguished under the name of Miltianthus? has penta- 

 gonal fruits not winged ; but the cal^x is developed and petaloid, while 



Fig. 503. 



Flower. 



1 The real situation of this inflorescence is 

 such that it corresponds probably to the axil of 

 a leaf placed lower, and has been drawn and 

 raised with the internode, above which it be- 

 comes free. This is an extraordinary fact in 

 most species of Zygophyllum, especially in the 

 various sections of the genus Guaiacum. (See 

 Adansonia, x. 312, 315.) 



2 In this case the inflorescence is a two- 

 flowered uniparous cyme. 



3 Neck., Elan., n. %7. 



4 The raphe is said to be free. 



5 A. Juss., in Mem. JIus., xii. 454, t. 15, 

 fig. 3. — Endl., Gen., n. 6035. 



6 Bge., in Linncea, xvii. 7, t. 1. — B. H., 

 Gen., 266. — H. Bx., in Adansonia, x. 315. 



' As is often the case iu the species of Zygo- 

 phyllum proper. 



8 Cham. & Schltl., in Walp. Ann., i. 495. 



9 Enum. PI. Lehm., 58, t. 9 (ex Arbt. d. 

 Nat. Ver. Riga, i. 197).— B.| H., Gen., 266, n. 

 7. — H. Bn., in Adansonia, x. 313. 



