672 



POLYGONACEAE. 



VOL. I. 



i. 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, i-3 high. Leaves 

 hastate, i'~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, 2\" 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: i8.3. pi. 

 189. 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, 2!" long, its angles crested with 

 3 prominent lobes above the mid<.'>, 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- 

 folitim Raf. 



Leaves sagittate ; achene 3-angled. 

 Leaves halberd-shaped ; achene lenticular. 



1. T. sagittatinn. 



2. T. arifolium. 



