672 



POLYGONACEAE. 



Vol. I. 



1. Fagopyrum Fagopyrum (L.) Karst. Buckwheat. Fig. 1646. 



Polygonum Fagopyrum L. Sp. PI. 364. 1753. 

 Fagopyrum esculentum Moench, Meth. 290.- 1794. 

 F. Fagopyrum Karst. Deutsch. Fl. 522. 1880-83. 



Annual, glabrous except at the nodes, stem 

 strongly grooved when old, l°-3° high. Leaves 

 hastate, 1/-3' long, abruptly narrowed above the 

 middle, acuminate, the nerves on the lower sur- 

 face slightly scurfy ; ocreae brittle and fugacious ; 

 racemes mostly panicled, sometimes corymbose, 

 many-flowered, erect or inclined to droop; pedi- 

 cels as long as the calyx ; segments white or whit- 

 ish ; stamens included ; style-branches deflexed 

 in fruit; achene acute, 2i" long, about twice as 

 long as the calyx, its faces pinnately-striate when 

 mature, the angles acute, entire. 



In waste places, and persistent in fields after culti- 

 vation. Reported from almost all parts of the north- 

 ern United States and southern British America. 

 Also in the West Indies. Native of eastern Europe 

 or western Asia. Brank. Corn-heath. Beech-wheat. 

 Crap. Saracen's-corn or -wheat. June-Sept. 



2. Fagopyrum tataricum (L.) Gaertn. 

 Tartary Buckwheat. Fig. 1647. 



Polygonum tataricum L. Sp. PI. 364. 1753. 



Fagopyrum tataricum Gaertn. Fr. & Sem. 2 : 182. pi, 

 180. f. 6. 1791. 



Annual, similar to the preceding species, but 

 the leaves deltoid-hastate or oblong-hastate, often 

 broader than long, i'-4' wide, acute or short- 

 acuminate at the apex; racemes terminal and 

 axillary, mostly solitary, simple and few-flowered, 

 long-peduncled ; flowers whitish, short-pedicelled ; 

 achene subacute, 2I" long, its angles crested with 

 3 prominent lobes above the middle, its faces 

 pinnately sulcate from a conspicuous groove. 



In waste places, eastern Canada and New England. 

 Rough buckwheat. Adventive from Asia. Summer. 



10. TRACAULON Raf. Fl. Tell. 3: 13. 1836. 



Annual or sometimes perennial prickle-armed herbs, with reclining-climbing 4-angled 

 stems. Leaves alternate, truncate, hastate or cordate, membranous, the petiole, midrib and 

 principal nerves armed with small recurved prickles. Ocreae oblique, finely nerved, vari- 

 ously roughened about the base. Flowers in terminal and axillary spike-like racemes, these 

 usually somewhat interrupted, or in capitate clusters. Sepals somewhat colored, 4-5, neither 

 keeled nor winged, enveloping the achene. Stamens varying from 5 to 8, included; fila- 

 ments not dilated. Styles 2 or 3, partially united, included. Achenes lenticular or 3-angled, 

 variously colored, strongly biconvex or three-angled, smooth and shining. Endosperm 

 horny. Cotyledons accumbent. [Greek, rough-stem.] 



About 18 species, natives mostly of North America and Asia. Type species: Tracaulon ari- 

 folium Raf. 



Leaves sagittate ; achene 3-angled. 

 Leaves halberd-shaped ; achene lenticular. 



1. T. sagittatum. 



2. T. arifolium. 



