THE APETALOUS ORDERS. 



463 



ternate leaves ; remarkable for their stipules (ochrese, 304), which 

 usually form sheaths around the stems above the leaves, and for 

 their orthotropous ovules. Stamens definite, inserted on the peta- 

 loid calyx. Fruit achenium-like, compressed or triangular. Em- 

 bryo curved, or nearly straight, applied to the outside (rarely in 

 the centre) of starchy albumen. Ex. Polygonum, Rumex (Dock, 

 Sorrel), Rheum (Rhubarb). The stems and leaves of Rhubarb 

 and Sorrel are pleasantly acid : while several Polygonums (Knot- 

 weed, Smart-weed, Water Pepper, &c.) are acrid or rubefacient. 

 The farinaceous seeds of P. Fagopyrum (the Buckwheat) are used 

 for food. The roots of most species of Rhubarb are purgative : 

 but it is not yet known what particular species of Tartary yield 

 the genuine officinal article. The ERIOGONE^: (of southern and 

 western North America) form a tribe remarkable for their exstipu- 

 late leaves and involucrate flowers. 



864. Ord, Lauraceft (the Laurel Family). Trees or shrubs, with 

 pellucid-punctate alternate leaves, their margins entire. Flowers 

 sometimes polygamo-dioecious. Calyx of four to six somewhat 

 united petaloid sepals, which are imbricated in two series, free 

 from the ovary. Stamens definite, but usually more numerous 

 than the sepals, inserted on the base of the calyx : anthers two- to 

 four-celled, opening by recurved valves ! Fruit a berry or drupe, 

 the pedicel often thickened. Seed with a large almond-like em- 



bryo, destitute of albumen. Ex. Laurus, Sassafras, Benzoin. 

 All aromatic plants, almost every part abounding in warm and 



FIG. 997. A staminate, and 993, a pistillate flower of Sassafras. 999. A stamen with its 

 glands at the base : the anthers opening by two sets of valves. 1000. Pistil ; the ovary divided. 

 1001 . Branch in fruit. 1002. Section of the drupe and seed. 



