578 PENJEACE^E. [Rhamnales. 



style and 4 half-indusiate stigmas ; ovules anatropal, either ascending, collateral, in 

 pairs, or solitary and suspended. Fruit capsular, 4 -celled, dehiscent or indehiscent? 

 Seed erect or inverted ; testa brittle ; embryo amygdaloid, exalbuminous, with two 

 very minute cotyledons ; hilum fungous. 



According to an observation of Jussieu, this Order is allied to Epacrids ; but I 

 confess myself unable to perceive in what manner. To me it formerly appeared 

 related to such apetalous dicotyledons as Proteads, with some of which the species 

 agree in habit, and in the case of Stylapterus even in the thickened connective 

 and the structure of the lobes of the stigma, each of which is strikingly like that of 

 a Grevillea. To Bruniads they may be compared, notwithstanding the presence of 

 petals in that Order, for the sake of Linconia, in which the pendulous ovule agrees 

 with Geissoloma, and of the thickened connective of the anthers, which is common to 

 several species, although not present in Geissoloma. The fungous hilum of the seed is 

 similar to that of Milkworts, with which, however, Penaeads have no other apparent 

 relation. It is, probably, to Rhamnads that the Order claims the nearest station, for 

 it corresponds with them in the important fact of the stamens being alternate with the 

 valvate lobes of the calyx, when the stamens are of an equal number, and it differs 

 from them principally in its peculiar anthers (and amygdaloid embryo). Its half- 

 indusiate stigmas are like those of some Ericads. 



The Order exhibits a singular instance of two distinct kinds of aestivation and 

 attachment of ovules among species which it seems unadvisable to separate from each 

 other. In true Penaea the aestivation is valvate and the ovules ascending, while in 

 Geissoloma the former is imbricate and the latter suspended. Penaea has also 

 tetrandrous flowers, with peculiarly fleshy anthers, while Geissoloma has octandrous 

 flowers, with no peculiar fleshiness in the anthers. 



M. Adr. de Jussieu, who has re-examined the Order, finds that the stigmas alternate 

 with the cells of the ovary, in the true Penaeads ; but that is certainly not the case 

 in Geissoloma. He has also ascertained that the great amygdaloid embryo of Penaea 

 has a minute cleft at one end, indicating rudimentary cotyledons. 



All are evergreen shrubs, natives of the Cape of Good Hope, and chiefly to the 

 eastward of the Hottentots Holland chain of mountains. 



A sub-viscid, sweetish, somewhat nauseous gum-resin called Sarcocol (Saptfo/c^AAa, 

 Diosc.) is said to be produced by various species. It was supposed by the Arabians to 

 possess, as its name indicates, the power of agglutinating wounds, and contains a 

 peculiar principle, named Sarcocollin, which has never been detected in any other 

 vegetable matter, and which has the property of forming oxalic acid, being treated 

 with nitric acid. Endlicher, however, remarks that this drug is not likely to be a 

 product of the present Order. Dioscorides says that it was obtained from a Persian 

 tree ; but whether that were so or not, the manifest relation of the drug called 

 Sarcocol to Galbanum and Sagapenum, renders it more likely to come from some 

 Umbellifer. 



GENERA. 



Pensea, X. 

 Sarcocolla, Kth. 

 Stylapterus, A. de J. 



Brachvsiphon, Id. 

 Endoneraa, Id. 

 Geissoloma, Lindl. 



Numbers. Gen. 6. Sp. 21. 



Bruniacece. 



Position' Pen^ace^;. — Rhaninacece. 



Proteacece. 



