134 
very hardwood, the branches often articulated at the joints. Leaves opposite, with stipules, 
very seldom simple, usually unequally pinnate, not dotted. Flowers solitary, or in pairs or 
threes, white, blue, or red, often yellow. 
Anomalies. Ovules occasionally erect. Tribulus has the fruit separating into spiny 
nuts, with transverse phragmata, and no albumen. Melianthus has very irregular flowers. 
Affinities. Nearly related to Oxalidacese, from which, however, they 
are distinguished by a multitude of characters. With Simarubacese they ac- 
cord in the stamens springing from the hack of a hypogynous scale ; a structure 
well worth more attentive consideration than it has yet received. Something 
analogous to it will be found in Silenacese. 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 the vegetation or habit of this order are, the 
leaves being constantly opposite, with lateral or intermediate stipules, being 
generally compound, and always destitute of the pellucid glands which univer- 
sally exist in true Rutaceae, 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 ZygophyUaceae. 
(See many good remarks upon this subject in Brown’s Appendix to Denham, 
P- - . . 
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. deJ. 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 
properties ; the bark and wood of Guaiacum sanctum and officinale have a 
somewhat bitter and acrid flavour, and are principally employed as sudorifics, 
diaphoretics, or alteratives ; they contain a particular matter often designated 
as resin or gum-resin, but which is now considered a distinct substance, called 
Guaiacine. DC. Porlieria hygrometrica has similar properties. The wood 
of Guaiacum officinale, or Lignum vitse, is remarkable for the direction of its 
fibres, each layer nf which crosses the preceding diagonally ; a circumstance 
first pointed out to me by Professor Voigt. 
GENERA. 
§ 1. Trieule^e, A.deJ.§ 2. Zygophylle^, 
Tribulus, L. 
Figaraea, Viv. 
Ehrenbergia, Mart. 
Kallstraemia, Scop. 
Biebersteinia, Steph. 
A. de J. 
Peganum, L. 
Fagonia, L. 
Seezenia, R. Br. 
Roepera, A. de J. 
Zygophyllum, L. 
Fabago, Tourn. 
Larrea, Cav. 
Porliera, R. et P. 
Guajacum, L. 
Trichanthera, Ehr. 
Anatropa, Ehr. 
Plectrocarpa, Hook. 
Melianthus, L. 
