476 CX. POLYGONACE^E. RUMEX 



16. P. ARIFOLIUM. Hastate Knotgrass. 



St. aculeate with reversed prickles; Ivs. hastate; spikes few-flowered; fls 

 distinct; sta. 6 ; sty. 2. (J) Wet grounds, Can. to Ga. and W. States. Distin- 

 guished from the last chiefly by its larger, halbert-shaped leaves, which are 

 2 4' long and % as wide. Petioles 1' long. Clusters racemose, slender 

 loose, few-flowered, at the ends of the branches. June, July. 



17. P. CONVOLVULUS. Knot Bindweed. 



St. twining, angular ; Ivs. cordate-hastate ; seg. of the cal. obtusely keeled ; 

 sta. 8 ; *ty. 3. (f) A common climbing species, in fields and waste grounds, Can. 

 to Ky. and Car. Stem 2 6f long, roughish, angled, with axillary branches. 

 Leaves 1 2' long, \ as wide, on petioles \ f ' long, with somewhat spreading 

 and acute lobes at base. Flowers whitish, in terminal, interrupted spikes, 

 June Sept. 



/?. cilinode. (P. cilinode. MX.) Plant minutely pubescent ; slip, fringed with 

 reflexed hairs at base. 



18. P. SCANDENS. Climbing Knotgrass. 



St. twining, smooth; Ivs. cordate, acuminate; seg. of the cal. winged; sta. 

 8; sty. 3. Tj. N. Eng. to Ark. Stem 3 7f long, climbing, often colored and 

 with axillary branches. Leaves heart-shaped, with distinct, rounded lobes. 

 Flowers in long, interrupted racemes. Calyx and fruit conspicuously 3-winged, 

 the wings decurrent on the slender, jointed pedicels. Aug. 



19. P. FAGOPYRUM. Buckwheat. St. erect, smooth; Ivs. cordate-sagittate; 

 rac. panicled; sta. 8; sty. 3; angles of the ach. equal. d) The name from the 

 Lat. fagus, beech, and pyrum, a pear ; the fruit resembles in shape a beech-nut. 

 Native of Asia, but here naturalized. A valuable grain cultivated for the flour 

 which is made into pan-cakes and eaten warm. Stems 2 4f high. Leaves 

 2 4' long, as wide. Flowers numerous, white, very grateful to bees. 



4. RUMEX. 



Calyx persistent, of 6 colored sepals, the 3 inner (valves) larger , 

 sta. 6 ; sty. 3, spreading ; stigmas many-cleft ; achenium 3-cornered. 

 covered by the 3 valve-like inner sepals. Herbs with the flowers in 

 dense, fasciculate panicles. 



$ 1. LAPATHUM. Flowers all $ . Inner sepals (valves) granuliferous. 

 * Inner sepals entire. 



1. R. CRISPUS. Yellow Dock. 



i/vs. lanceolate, waved, acute; valves (inner sepals) of the cal. entire, ovate, 

 each bearing a tubercle. Tj. Can. and U. S. A weed so common as hardly to 

 need description, growing in cultivated grounds, about rubbish, &c., much to 

 the annoyance of the farmer. Stem 2 3f high, smooth, channeled, from a yel- 

 low, fusiform root. Flowers numerous, in a large panicle, consisting of many 

 racemes of half-whorls, interspersed with leaves. Calyx-valves 3, enclosing 

 the seed, each with a grain on the back. The root is used in medicine for cuta- 

 neous diseases. June. $ 



2. R. SANGUINEUS. Bloody-veined Dock. 



L/vs. petiolate, cordate, lanceolate; valves of the cal. entire, one of them 

 principally bearing the granule. 1J. Can. and N. States. Stem of a reddish 

 color, branching, leafy, 2 3f high. Leaves smooth, radical ones large, mostly 

 with red veins, somewhat cordate, slightly curled at the edges. Flowers in 

 small, distant whorls. Grows in waste and shady places. July. 



3. R. ERITTANICUS. British Water Dock. 



I/vs. broad-lanceolate ; joints with nearly obsolete, torn sheaths ; Jls. poly- 

 gamous; valves entire, all bearing granules. 7J. Can., U. S. Aquatic, growing 

 in muddy places. ' Root yellow internally, large. Stem 3f high, furrowed, 

 angular and branched. Leaves large, petiolate, acute. Flowers in verticillate 

 fascicles, collected into a large, terminal panicle. Pedicels nodding in fruit. 

 Calyx valves large, cordate, July. 



