Rhamnales.] 



PENiEACE^. 



577 



Order CCXIX. PEN^ACEiE.— Sarcocollads. 



Penaeaceae, R. Brown, verbally, (1820); Guillemin in Diet. Class. 13. 171. (1828); Kunth in Linnaa, 

 V. 667. (1830) ; Endl. Gen. cxii.; Meisner Gen. p. 329.— Geissolomeae, Endl. Ench. p. 214. 



Diagnosis. — Rhamnal Exofjens, with apetalous flowers, an ovary composed of 4 carpelSf a 

 tubular calyx, with definite divisions, and 2 consolidated cotyledons. 



Shrubs. Leaves opposite, imbricated, without stipules. Flowers terminal and axil- 

 lary, usually red. Calyx mferior, with 2 or more bracts at its base ; hypocrateriform, 

 with a 4-lobed limb, valvate or imbricated 

 in aestivation. Stamens either 4, arismg from 

 below the recesses of the Umb, with which they 

 alternate, or 8, arising from near the base of 

 the calyx ; anthers 2-celled, tui'ned inwards, 

 usually with membranous valves Ipng on the 

 face of a thick fleshy connective, sometimes 

 with fleshy valves, and an obliterated connective. 

 Ovary superior, 4-celIed, with a simple style 

 and 4 half-indusiate stigmas ; ovules anatropal, 

 either ascending, collateral, in pairs, or sohtary 

 and suspended. Fruit capsular, 4 -celled, de- 

 hiscent or indeliiscent ? Seed erect or mverted ; 

 testa brittle ; nucleus a solid fleshy mass, ^vith 

 no distinction of albumen or embi'yo ; hilum 

 fungous. 



According to an observation of Jussieu, this 

 Order is alhed to Epacrids ; but I confess my- 

 self unable to perceive on what account. To 

 me it fonnerly appeai'ed related to such apeta- 

 lous dicotyledons as Proteads, with some of 

 wliich the species agree in habit, and in the 

 case of Pensea fmticulosa even in the thick- 

 ened connective and the structm-e of the lobes 

 of the stigma, each of which is strikingly hke 



that of a Gre\illea. 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 fmigous hilum of the seed is 

 similar to that of Milkworts, with which, however, Penseads have no other appai'ent 

 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 undivided embryo ?). Its half- 

 indusiate stigmas are hke those of some Heathworts. 



The Order exhibits a singular instance of two distinct kmds of aestivation and attach- 

 ment of ovules among species wliich it seems unad\asable to separate from each other. 

 In true Pensea the aestivation is valvate and the o\ades ascending, while in Geissoloma the 

 former is imbricate and the latter suspended. Penaeahas also tetrandi-ous flowers, with 

 pecuharly fleshy anthers, while Geissoloma has octandrous flowers, with no peculiar 

 fleshiness in the anthers. 



All are evergi-een shnibs, natives of the Cape of Good Hope, and chiefly those to the 

 eastward of the Hottentots Holland chain of mountains. 



A sub-viscid, sweetish, somewhat nauseous gum-resin called Sarcocol (Sop/co/cdAAo, 

 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 contams a peculiar 

 principle, named SarcocolUn, which has never been detected m any other vegetable 

 matter, and which has the property of foi-ming oxalic acid, being treated with mtric 



CCCXCI. 



Fig. CCCXCI.— Peiiffia fruticulosa. 1. a flower ; 2. a portion of the calyx with a stamen attached ; 

 3. an anther ; 4. a pistil, with one of the cells cut open ; 5. a seed ; 6. a section of it. 



P P 



