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CXIX. ZYGOPHYLLEiE. The Bean Caper Tribe. 



Zygophylleje, R. Brown in Minders, (1814); Dec. Prodr. 1. 703. (1824); Adrian de Juss. 



Rutacces, 67. (1825.) 



Diagnosis. Polypetalous dicotyledons, with definite hypogynous stamens, 

 concrete carpella, an entire ovarium of several cells, an imbricated calyx, sym- 

 metrical flowers, pendulous ovules, stamens arising from hypogynous scales, 

 and opposite stipulate leaves without pellucid dots. 



Anomalies. Ovules occasionally erect. Tribulus has the fruit separated 

 into spiny nuts, with transverse phragmata, and no albumen. Melianthus has 

 very irregular flowers. 



Essential Character. — Flowers monoclinous, regular. Calyx divided into 4 or 5 pieces 

 with convolute aestivation. Petals unguiculate, alternate with the segments of the calyx and 

 a little longer, in activation, which is usually convolute, at first very short and scale-like. 

 Slamens double the number of the petals, dilated at the base, sometimes naked, sometimes 

 placed on the back of a small scale, hypogynous. Ovarium simple, surrounded at the base 

 with glands or a short einous disk, more or less deeply 4- or 5-furrowed, with 4 or 5 cells ; 

 ovula in each cell 2 or more, attached to the inner angle, pendulous, or occasionally erect; 

 style simple, usually with 4 or 5 furrows ; stigma simple, or with 4 or 5 lobes. Fruit capsu- 

 lar, rarely somewhat fleshy, with 4 or 5 angles or wings, bursting by 4 or 5 valves bearing the 

 dissepiments in the middle, or into as many close cells; the sarcocarp not separable from the 

 endocarp. Seeds usually fewer than the ovules, either compressed and scabrous when dry, or 

 ovate and smooth, with a thin herbaceous integument. Embryo green ; radicle superior ; co- 

 tyledons foliaceous ; albumen whitish, between horny and cartilaginous, in Tribulus want- 

 ing. Ad. J. — Herbaceous plants, shrubs, or trees, with a very hard wood, the branches often 

 articulated at the joints. Leaves opposite, with stipula;, very seldom simple, usually une- 

 qually pinnate, not dotted. Flowers solitary, or in pairs or threes, white, blue, or red, often 

 yellow. 



Affinities. Nearly related to Oxalideee, from which, however, they are 

 distinguished by a multitude of characters. With Simarubacere they accord 

 in the stamens springing from the back of a hypogynous scale ; a structure 

 well worth more attentive consideration than it has yet received. Something 

 analogous to it will be found in Caryophylleffi. M. Adrien de Jussieu also 

 observes that the petals are remarkable for their being, in an early state, minute 

 and hidden by the calyx, which they only exceed about the time of flowering, 

 while in other Rutaceous orders the petals are always larger than the calyx. 

 The distinguishing characters in its vegetation or habit are, the leaves being 

 constantly opposite, with lateral or intermediate stipule, being generally com- 

 pound, and always destitute of the pellucid glands which universally exist in 

 true DiosmeK. Brown in Denham, 26. It is also a very common character 

 of the order to have the radicle at that extremity of the seed which is most 

 remote from the hilum ; but this, which is of great importance in many natural 

 families, is of less value in Zygophylleae. (See many good remarks upon this 

 subject in Mr. Brown's Appendix to Denham, p. 27.) 



Biebersteinia, appended to this order by A. de Jussieu, is a genus that requires 

 further examination. 



Geography. Guaiacum, Porlieria, and Larrea, are peculiar to America. 

 Fagonia is distributed over the south of Europe, the Levant, Persia, and India. 

 Zygophyllum inhabits the same regions, and also the south of Africa, and is 

 represented in New Holland by Ropera. Tribulus is found in all the Old 

 World within the tropics, or in countries bordering upon them. Ad. de J. Me- 

 lianthus, a most anomalous genus, is remarkable for being found both at the 

 Cape of Good Hope and in Nipal, without any intermediate station. 



Properties. Zygophyllum Fabago is sometimes employed as an anthel- 

 mintic. The ligneous plants of the order are remarkable for the extreme hard- 

 ness of their wood. All the Guaiacums are well known for their exciting pro- 



