380 POLYGONACEAE 



often acuminate at the apex, ciliate, more or less papillose, undulate or slightly crisped, 



punctate, containing a very acrid juice : ocreae 0.5-1 cm. long, fringed with long bristles, 



usually enlarged about the bases, often bearing one or two flowers within : racemes linear, 



2-6 cm. long, drooping, much interrupted : ocreolae funnelform, 1.5-2 mm. long : slightly 



oblique, fringed with a few siiort bristles : calyx greenish, 2.5-3 mm. long : sepals rather 



narrowly oblong, obtusish, glandular : stamens 4 or sometimes 6 : achenes lenticular, 



biconvex, slightly gibbous, or 3-angled, 3 mm. long, broadly oblong or ovoid, sometimes 



orbicular or even broader than high, short-tipped, dark brown, strongly granular and dull. 



\_ Polygonum Hydropiper L.] 



Common in moist or waste places, almost throughout North America. Naturalized from Europe 

 southward and eastward, said to l)e native in the north and west. Water Pepper. 



18. Persicaria orientalis (L. ) Vilm. Annual, large, more or less hispid. Stem 

 erect, 4-25 dm. tall, becoming woody below : leaf-blades ovate or broadly oblong, 6-25 

 cm. long, acuminate, varying from acute to cordate at the base, ciliate, hispidulous on tlie 

 midrib and its lateral branches on both surfaces ; petioles 2-8 cm. long, slightly winged : 

 ocreae 1-3 cm. long, with asi)reading border at the summit, 'ciliate : racemes varying from 

 oblong to linear, 3-10 cm. long, drooping or sometimes suberect, often slightly interrupted 

 near the base : ocreolae funnelform, 3-5 mm. long, very oblique, ciliate : calyx dark rose- 

 colored, 4-4.5 mm. long : stamens 7 : achenes lenticular, 3 mm. long, orbicular or broader 

 than high, thickened laterally about the base, biconcave, minutely granular and rather dull. 

 {^Polygonum orientale L.] 



In waste places, generally. Naturalized from India. Summer and fall. Prince's Feather. 



9. FAGOPYRUM Gaertn. 



Annual caulescent smooth and usually glabrous herbs. Leaves alternate : blades 

 entire, hastate or cordate : ocreae oblique, entire. Flowers perfect, white or whitish, 

 several together on slender pedicels subtended by an ocreola. Racemes in cluster-like 

 cymes or corymbs. Calyx corolloid, pei'sistent and unchanged in fruit. Sepals about equal. 

 Stamens 8 : filaments filiform, glabrous. Ovary 3-angled : styles 3 : stigmas capitate. 

 Ovule erect. Achene 3-angled, its anglers slightly margined or crested, its faces transversely 

 striate. Embryo dividing the mealy endosperm by an S-shaped curve. 



1. Pagopyrum Fagopyrum (L. ) Karst. Rather fleshy when young. Stem 1-9 dm. 

 tall, erect, simple or branched, with a little pubescence about the nodes : leaf-blades 

 hastate, 2.5-8 cm. long, cordate, petioled, abruptly narrowed above the middle : ocreae 

 brittle and fugacious : racemes many-flowered, erect or inclined to droop, continuing to 

 flower after fruit is produced : calyx white or whitish : pedicel as long as the calyx, one- 

 half as long as the achene or shorter : achenes broadly ovoid, acute, 5 mm. long, the faces 

 jiinnately-striate when mature, and slightly variegated, the angles acute, entire. 



In waste places, about cultivated fields and along railroads, more or less persistent. Adventive 

 from eastern Europe and western Asia. Summer. Buckwheat. 



10. TRACAULON Raf. 



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

 stems. Leaves alternate : blades truncate, hastate or cordate, membranous, the petiole, 

 midrib and principal nerves armed with small recurved prickles. Ocreae oblique, finely 

 nerved, variously 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 : filaments 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. The plants flower in the summer 

 and fall, or earlier in the extreme south. Tear-thumb. 



Leaf-blades sagittate or subsagittate : achenes 3-angled. 



Inflorescence dichotomous : leaf-blades sessile or nearly so : achenes blunt-angled. 



1. T. Beyrichianum. 

 Inflorescence not dichotomous : leaf-blades manifestly petioled : achenes sharp-angled. 



2. T. safiitfatum. 

 Leaf-blades hastate : achenes lenticular. 3. T. arij'olium. 



1. Tracaulon Beyrichianum < Cham. & Schlecht. ) Small. Perennial, somewhat wiry. 

 Stem 5-10 dm. long, reclining, dichotomously branched, slightly enlarged at the nodes, 



