169 



CLV. PETIVERIACEiE. 



Petiverie^e, Agardh Classes, (1825).— Petiveriace.e, Link Handb. 1.392. (1829.) 



Diagnosis. Apetalous dicotyledons, with definite erect ovula, an in- 

 ferior many-leaved calyx, distinct perigynous stamens, an exalbuminous 

 embryo with spiral cotyledons, and the radicle next the hilum. 



Anomalies. 



Essential Character. — Calyx of several distinct leaves. Stamens perigynous, 

 either indefinite, or, if equal to the segments of the calyx, alternate with them. Ovarium 

 superior, l-ceUed; styles '6 or more; stigma lateral; ovulum erect. Fruit 1 -celled, inde- 

 hiscent, dry. Seed erect, without alhumen ; embryo straight ; cotyledons convolute ; radicle 



inferior Under-shritbs or herbaceous plants, with an alliaceous odour. Leaves alternate, 



entire, with distinct stipulse, often with minute pellucid dots. Floivers racemose. 



Affinities. Obviously akin both to Phytolaccese and Polygonece, with 

 the former of which Mr. Brown combines them. They are, however, dis- 

 tinguished from Phytolaccegg by the presence of stipulse, and by their straight' 

 embryo destitute of albumen, and spiral cotyledons. From Polygoneae they 

 are known by the same characters, and also by the radicle being turned 

 towards the hilum, and the stipulse not having the form of Ochreae. 



Geography. West Indian or tropical American plants; for the Se- 

 guiera asiatica of Loureiro probably does not belong to the order. 



Properties. Nothing is known of their qualities, except that Petiveria 

 alliacea yields a strong smell of garlic. 



Examples. Petiveria, Seguiera. 



CLVI. POLYGONE^. The Buck-wheat Tribe. 



P0LYGONE.1:, Juss. Gen. 82. (1789) ; R. Brown Prodr. 418. (1810); Lindl. Synops. 209. 



(1829.) 



Diagnosis. Apetalous dicotyledons, with definite erect ovula, ochreate 

 stipulse, and a radicle remote from the hilum. 



Anomalies. Eriogonum has not ochreate stipulse. 



Essential Character. — Calyx divided, inferior, imbricated in aestivation. Sta- 

 mens definite, inserted in the bottom of the calyx ; anthers dehiscing lengthwise. Ovarium 

 superior, with a single erect ovulum ; styles or stigmas several. Nut usually triangular, 

 naked, or protected by the calyx. Seed with fai-inaceous albumen, rarely with scarcely any ; 

 embryo inverted, generally on one side ; plumula inconspicuous ; radicle at the end remote 

 from the hilum — Herbaceous plants, rarely shrubs. Leaves alternate, their stipulae coher- 

 ing round the stem in the form of an ochrea ; when young, rolled backwards. Flowers occa- 

 sionally unisexual, often in racemes. 



Affinities. Mr. Brown remarks, that " the erect ovulum with a supe- 

 rior radicle together afford the most important mark of distinction between 

 Polygoneae and Chenopodese, a character which obtains even in the genus 

 Eriogonum, in which there is no petiolar sheath, and scarcely any albumen, 

 the little that exists being fleshy." Generally speaking, however, the cohe- 

 sion of the scarious stipula; into a sheath, technically called an ochrea, or 

 boot, is sufficient to distinguish Polygoneae from all other plants. For their 

 relation to Begoniaceae, see that order. 



Geography. There are few parts of the world that do not acknow- 

 ledge the presence of plants of this order. In Europe, Africa, North Ame- 



