veral varieties often described as distinct 

 species, is widely spread over Central and 

 Southern America, and is sometimes plant- 

 ed for its sweetish succulent pods, used for 

 cattle-feeding, called Algarobo after the 

 Spanish Algarobo or Ceratonia, which it 

 resembles in flavour. The P. spicigera, in 

 the East Indies, has also a sweet pod there 

 compared to the Algarobo. P. Stephaniana, 

 sometimes separated as a distinct genus un- 

 der the name of Lagonychium, is a scrubby 

 prickly bush, common in Syria and North- 

 ern Persia, with an irregularly curled or 

 twisted pod. P. torquata, and some other 

 South American shrubby species, have a 

 very curious spirally twisted pod like a 

 corkscrew. The pods of several species 

 supply a large quantity of tannin. 



P. glandulosa, the Mezquit of Texas and 

 the regions to the west, in some situations 

 forms a tree thirty feet high, and yields 

 excessively hard and durable timber, and 

 likewise affords a large quantity of gum 

 resembling gum-arabic. P. pubescens, 

 also a native of Texas, New Mexico, and 

 California, is the Screw-bean or Screw Mez- 

 quit of the Americans, and the Tornillo of 

 the Sonora Mexicans, and is so called from 

 the screw-like form of its pods. 



PROSTANTHERA. A genus of Labiatce, 

 having the corolla somewhat bell-shaped, 

 the upper lip bifid, the lower tiiree-lobed, 

 the middle lobe largest ; and the anthers 

 furnished with spurs beneath. The species j 

 are Australian shrubs, with a powerful 

 odour. P. lasianthos has been long known | 

 in cultivation, having been one of the ear- 

 liest of the species introduced ; its leaves i 

 are lanceolate and serrate, the corolla hairy. 

 The name is from the Greek for 'append- 

 age 'and 'anther,' in allusion to a promi- 

 nent character of the genus. [G. D.] 



PROSTEA. A large tree from tropical 

 Africa, proposed by Cambessedes as a ge- 

 nus of Sapindacece, but now considered as 

 a species of Deinballia. 



PROTEACE^. (Proteads.) A natural 

 order of monochlamydeous dicotyledons 

 belonging to Lindley's daphnal alliance of 

 perigynous Exogens. Perianth four-parted, 

 valvate ; stamens four (one sometimes ste- 

 rile), opposite the segments of the perianth, 

 the anthers bursting lengthwise; ovary 

 superior, one-celled ; ovules erect, the style 

 simple, and the stigma undivided ; seed 

 exalbuminous. They form shrubs or small 

 trees, with hard dry opposite or alternate 

 exstipulate leaves ; and are natives princi- 

 pally of Australia and the Cape of Good 

 Hope. In general they occur in land unfit 

 for cultivation, and seldom attain to a con- 

 siderable size. In the section Nucumen- 

 taeecp the fruit is nucumen taceous and 

 indehiscent ; and in Follicidares it is folli- 

 cular and dehiscent. Protect, Persnonia, Gre- 

 villea, Hakea, Banksia, and Dryandra are 

 examples of the genera, some forty-six in 

 number, comprising over 600 species. 



They have no medicinal properties of im- 

 portance, but present great diversity of 

 aprearance— hence the name of the order ; 



and they are cultivated for theirhandsome 

 habit, and the peculiarity of their flowers. 

 The clustered cone-like heads of the flowers 

 of Banksia are very remarkable. In Gre- 

 villea the style is at first bent downwards, 

 and the discoid stigma is enclosed within 

 the upper part of the perianth where the 

 anthers are placed ; but after the pollen has 

 been scattered the stigma is emancipated, 

 and the style rises upwards. The fruit and 

 seeds of a few plants of the order are eaten, 

 and the wood is used for economical pur- 

 poses. Guevina Avellana yields nuts, which 

 are sold in Chili under the name Avellano. 

 Protea mellifera is called Sugar-bush, on 

 account of the honey furnished by its 

 flowers. Leucadendron argenteum is the 

 Witteboom of the Cape. [J. H. B.] 



PROTEA. A large chiefly South African 

 genus of Proteacea?, one species, P. abys- 

 sinica, being a native of Abyssinia. The 

 genus is distinguished by having an elon- 

 gated unequally divided two-parted calyx, 

 the broader lip bearing three nearly sessile 

 stamens, the narrower lip one ; and by the 

 awl-shaped style having a cylindrical acu- 

 minate stigma. Fruit a hairy nut contain- 

 ing a single seed. The flowers are terminal 

 or axillary, in large heads six to eight inches 

 in diameter, surrounded in some species 

 by coloured bracts four inches in length 

 and half an inch broad.their apices crowned 

 with long silky hairs. The plants them- 

 selves form small trees or shrubs with 

 very variable foliage. In P. speciosa, P. 

 mellifera, P. longifolia, P. coccinea, P. nerii- 

 folia, the leaves are oblong with a narrow 

 base ; in P. cordata, P. latifolia, P. speeta- 

 bilis, &c.,th ey are heart-shaped ; in P. caffra, 

 P. abyssinica, P. pencillata, &c, they are 

 lanceolate; and in P. pidchella, P.formosa, 

 P. acerosa, P. scabra, &c, they are linear 

 and sharp-pointed. [R. H.] 



PROTERANTHOTJS. Having leaves 

 which appear before the flowers. 



PROTHALLUS. A term intended to in- 

 dicate the first results of the germination 

 of the spores in the higher cryptogams. 

 In ferns it is a little kidney-shaped or 

 rounded membrane; in adder's-tongues a 

 little bulb-like body ; in horsetails a bundle 

 of adnate threads; in Selaginella, Isoetes, 

 and Marsileacece, a cellular expansion con- 

 fluent with the spore. In all these cases 

 the new plant springs from the impregna- 

 tion of a cell in peculiar organs called ar- 

 chearonia. The term Prothallus is not ap- 

 plied to the germinating threads in mosses 

 and liverworts, which produce the plant at 

 once without impregnation, that process 

 resulting in the formation of a capsule, 

 and not of a new plant. [M. J. B.] 



PROTOCOCCUS. A genus of chloro- 

 spermous Algce, consisting of plants com- 

 posed of a single cell propagated by the 

 organisation of the endochrome, which is 

 repeatedly divided into four, the individual 

 spores for a time moving about by means 

 of fiagelliform appendages. The species col- 

 lected under the name do not probably pre- 



