POLYGONACEAE 251 



Stem 6 to 12 or 15 inches high, slender, branching, somewhat angular and fur- 

 rowed. Leaves 1 to 2 inches long, the lower ones mostly all hastate, and on 

 petioles as long or longer than the leaves, the upper ones on short petioles, and 

 not hastate. Verticils of flowers halved, 6- to 8- flowered. Pistillate plants mostly 

 taller than the staminate. 

 Hub. Sandy grounds. Nat. of Europe. Fl. May. Fr. Aug. 



Obs. This little weed (well known for its acid juice,) is often so 

 abundant as to be a nuisance on the farm. 



354. RHE V UM, L. 



[Named from Rha, the ancient name of the river Volga, its native region.] 

 Calyx of 6 sepals, withering and persistent. Stamens 9, in pairs 

 opposite the outer sepals, single opposite the inner ones. Styles 3, 

 short; 'stigmas large, multifid, Akene triquetrous, winged at the 

 angles; embryo straight, in the centre of the albumen. Stout 

 perennials : leaves chiefly radical, very large ; flowers fasciculate, 

 racemose-paniculate. 



1. R. RHAPONTICUM, Ait. Leaves cordate-ovate, rather obtuse, 

 the sinus at base dilated ; petioles with a shallow channel above, 

 rounded at the edges. 

 RHAPONTIC RHEUM. Pie Rhubarb. 



Soot tuberous, large, reddish-brown, yellow within. Stem 3 to 5 feet high, stout, 

 Btriate-sulcate, smoothish, fistular, paniculately branched above. Radical leaves 

 1% to 2 feet long ; petioks 5 to 10 or more inches in length, thick and fleshy ; 

 stipules large, membranaceous, sheathing. Flowers greenish, with white edges; 

 pedicels % to % an inch long, articulated near the middle. ' 



nab. Gardens. Nat. of Seythia. Fl. May. Fr. July. 



Obs. Cultivated for its stout acid petioles, which are used by 

 the pastry cook, in early spring, as a substitute for fruit. 



ORDER LXXX. LAURA^CEAE. 



Aromatic trees, or shrubs ; leaves alternate, simple, without stipules ; flowers clus- 

 tered, often polygamo-dioicous; calyx of 4 to 6 colored sepals, imbricated in 2 rows 

 in the bud; stamens definite, usually more numerous than the sepals; anthers 

 introrse, 2- to 4-celled, opening by uplifted persistent valves! style single; fruit a 

 fterry, or drupe ; seed solitary, destitute of albumen. 



The tropical plants of this Order are interesting, affording Cinnamon, Cassia, 

 and Camphor ; and also that species of Laurus (L. nobilis, L.) of which the Ancients 

 formed their Laurel wreaths, or crowns. 



355. SASSAFRAS, Nets. 



[Altered from Salsafras, the popular Spanish name.] 



Flowers dioicous: Sepals 6, united at base. STAM. FL. Stamens 

 9, in 3 series, the 3 innermost each with a pair of stipitate glands 

 at base ; anthers 4-celled. PISTILLATE FL. with 6 rudiments of 

 stamens. Drupe ovoid, on a clavate fleshy peduncle. Trees : leaves 

 often lobed, but the margins entire ; flowers greenish-yellow, coaeta- 

 neous, in terminal bracteate corymbose racemes. 



1. S. officinsUe, Nees. Leaves ovate, or some of them 2- or 3- 



