j being either unequal or nearly equal ; and 

 twelve stamens in four series, the inner 



] one of which is sterile and the three outer 



I fertile, with four-celled anthers, the inner 

 series of fertile ones having two globular 



I stalked glands at their bases. All the spe- 

 cies are trees, with alternate entire arch- 

 nerved leaves, and panicles of small flowers 

 in clusters, producing large fleshy one- 

 seeded fruits, supported upon a thickened 

 stalk. 



P. gratissima, the Avocado or Alligator 

 Pear, is a common tree in tropical America 

 and the West India Islands, where it at- 

 tains the height of twenty-five or thirty 

 feet. It has elliptical leaves, narrow to- 

 wards the base and about six inches long, 

 and bears large pear-shaped fruits covered 

 with a smooth brownish-green or deep- 

 purple skin. These fruits are highly es- 

 teemed in the West Indies and tropical 

 America, though strangers at first do not 

 relish them. They contain a large quantity 

 of firm pulp possessing a buttery or mar- 

 row-like caste, and are hepce frequently 

 called Vegetable Marrow or Midshipman's 

 Butter. It is usually eaten with spice, lime- 

 juice, or pepper and salt. An abundance 

 of oil, useful for illuminating purposes and 

 for soapmaking, may be obtained from the 

 pulp by expression. The seeds yield a deep 

 indelible black stain, and are used for 

 marking linen. [A. S.] 



PERSIAN-BERRIES. The seeds of 

 JBhamnus infectorius. 



PERSICA. The Peach, Amygdalus Per- 

 sica. 



PERSICARY. Polygonum Persicaria. 



PERSICAIRE. (Fr.) Polygonum. — DU 

 LEVANT. Polygonum orientate. 



PERSIL, or P. COMMUN. (Fr.) Petro- 

 seUnura sativum. — A LARGES FEU- 

 ILLES. Petroselinum peregrinum. — 

 BATARD. Caucalis latifolia. — DANE. 

 Anthriseus sylvestris. — DE MACE"DOINE. 

 Athamanta macedonica. — DES MARAIS. 

 Apium graveolens. — DES MONT AGNES. 

 Athamanta; also Ligusticum Levisticum. — 

 FRISE. Curled Parsley — SAUVAGE. 

 Anthriseus vulgaris. 



PERSIMMON. Biospyros virginiana. 



PERSISTENT. Not falling off, but re- 

 maining green until the part which bears 

 it is wholly matured : as the leaves of ever- 

 green plants. 



PERSONAT2E. A name given by Lin- 

 naeus to a natural order embracing certain 

 plants which have irregular gamopetalous 

 ormonopetalous corollas: such as figworts, 

 yerbenas, bignonias, &c. 



PERSONATE. A term applied to a mo- 

 nopetalous corolla, the limb of which is 

 unequally divided : the upper division or 

 lip being arched, the lower prominent and 

 pressed against It, so that when compressed 

 the whole resembles the mouth of a gaping 

 animal ; as the corolla of Antirrhinum. 



PERSOONIA. An extensive genus of 



Proteacace, distinguished by having a calyx 

 of four equal sepals, sometimes only four- 

 cleft, thickened at the base, which occasion- 

 ally is enlarged into a small sac ; by having 

 a stamen inserted on the middleof each 

 sepal or segment ; by its filiform style, 

 generally longer than the stamens, straight 

 or curved, with an obtuse stigma; and by 

 its one or two-celled fruit being a drupe, 

 with a leathery covering, and having a 

 I single seed in each cell. The flowers are 

 I generally solitary, but at times are pro- 

 ! duced in terminal spikes, often clothed 

 I with brownish hairs. The leaves are scat- 

 tered, leathery in texture ; needle-shaped 

 as in P. microcarpa, pini/olia, tenuifolia, 

 ' and Cliamcepitys ; linear as in P. mollis and 

 : longifolia ; lanceolate as in P. angulata and 

 . daphnoides ; obovate as in P. elliptica, mar- 

 ginata, velutina, and cornifolia ; and oval 

 i and acuminate as in P. Cnnninghamii. 

 They form trees or large shrubs, and are 

 j found in most parts of Australia. One 

 species, P. Toro, a lofty tree, is found in 

 New Zealand. [R. H.] 



PEB.TUSARIA. A genus of lichens be- 

 longing to the natural order Endocarpei, 

 which are characterised by a pale single or 

 double perithecium piercing the horizontal 

 thallus by a distinct ostiolum. PeHusaria 

 | is distinguished by the perithecia being 

 sunk several together in wart-like pro- 

 cesses, while in Porina, separated from it— 

 the species of which are inhabitants of 

 warm climates, while those of Pertusaria 

 belong more especially to the temperate 

 zones— the perithecia are solitary. Pertu- 

 saria has large sporidia, which become blue 

 when treated with iodine. P. communis is 

 one of our commonest lichens on the trunks 

 of trees. When barren, the mealy disks 

 called soredia, which are so common on 

 lichens, abound to such a degree that it 

 assumes a totally different habit, and with 

 some other metamorphosed species consti- 

 tutes the spurious genus Variolar ia. This 

 again, especially on old trunks, spreads 

 with the growth of the bark for many 

 inches, and the soredia predominating 

 over the crust it assumes the name of 

 Lepraria. [M. J. B.] 



PERTUSE. Having slits or holes. 



PERULE. The covering of a leaf-bud 

 formed by scales ; also a projection in the 

 flower of orchids formed by the enlarge- 

 ment of two lateral sepals. See Mentum. 



PERVENCHE. (Fr.) Vinca. — DU CAP. 

 Vinca rosea. — , GRANDE. Vinca major. 

 — , PETITE. Vinca minor. 



PERVILLyEA. A genus of Asclepiadacea, 

 consisting of onlyone species, P. tomentosa, 

 a Madagascar twiner, with opposite broad 

 oval or obovate leaves, tomentose on the 

 under-surface, and cymose flowers, of a 

 yellowish colour blotched with purple. The 

 calyx is five-cleft, the corolla rotate, and 

 the fruit oblong, covered with woolly hair, 

 and enclosing comose seeds. [B. S.J 



PESCATOREA. This genus of orchids 

 was founded upon a species from Veraguas, 



