GENUS 7. 



BUCKWHEAT FAMILY. 



667 



In waste places, throughout temperate North America. Naturalized from Europe. Some- 

 times a troublesome weed. Native also of Asia. Willow-weed. June-Sept. 



Persicaria tomentosa (Schrank) Bicknell (Polygonum tomentosum Schrank) has been sepa- 

 rated from P. lapathifolia by the pubescent leaves and slightly larger flowers and fruits. 



4. Persicaria portoricensis (Bertero) Small. 

 Dense-flowered Persicaria. Fig. 1633. 



Polygonum densifiorum Meisn. in Mart. Fr. Bras. 5: Part 



i, 13. 1855. Not Blunie, 1825-26. 

 Polygonum portoricense Bertero ; Meisn. in DC. Prodr. 



14: 121. 1856. 

 Persicaria portoricensis Small, Fl. SE. U. S. 377. 1903. 



Perennial, more or less scurfy; stem erect, decum- 

 bent or floating, 3-5 long or longer, branched, en- 

 larged at the nodes, often dark brown. Leaves lan- 

 ceolate or linear-lanceolate, ii'-i2' long, acuminate 

 at both ends, obscurely punctate, short-petioled. the 

 nerves prominent beneath ; ocreae cylindric, sometimes 

 bristly when young, naked when mature, sometimes 

 hispid ; racemes spicate, paniculate, often in pairs, I'-j' 

 long, dense, erect ; calyx white or whitish, 5-parted to 

 near the base; stamens 6-8, included; style 2-3-cleit, 

 somewhat exserted ; achene lenticular and strongly 

 biconvex or 3-angled, i"-\\" long, broadly oblong, or- 

 bicular or even broader than high, black, smooth and 

 shining, or minutely granular. 



In wet soil, southern New Jersey and Missouri to Florida, Texas, the West Indies and South 

 America. May-Nov. 



5. Persicaria pennsylvanica (L.) Small. Penn- 

 sylvania Persicaria. Fig. 1634. 



Polygonum pennsylvanicum L. Sp. PI. 362. 1753. 

 Persicaria pennsylvanica Small, Fl. SE. U. S. 377. 1903- 



Annual, glabrous below ; stem erect, simple or branched, 

 i-3 tall, the upper parts, the peduncles and pedicels 

 glandular. Leaves lanceolate, acuminate at the apex, 

 petioled, ciliate, 2'-ii' long, the upper sometimes glandu- 

 lar beneath; ocreae cylindric, thin, naked, glabrous; 

 racem.es panicled, erect, thick, oblong or cylindric, dense, 

 i '-2' long; calyx dark pink or rose-color, 5-parted; 

 stamens 8 or fewer, style 2-cleft to about the middle; 

 achene orbicular or mostly broader than high, I*" long, 

 short-pointed, lenticular, smooth, shining. 



In moist soil, Nova Scotia to Ontario, Minnesota, Florida 

 and Texas. Ascends to 2000 ft. in Virginia. July-Sept. 



Persicaria omissa (Greene) Small, differing by an ovoid 

 achene and copiously glandular peduncles, recently found in 

 western Kansas, was first discovered in Colorado. 



6. Persicaria longistyla Small. Long-styled 

 Persicaria. Fig. 1635. 



Polygonum longistylum Small, Bull. Torr. Club 21 : 



169. 1894. 

 Persicaria longistyla Small, Fl. SE. U. S. 377. 1903. 



Annual or perennial, glabrous except the glan- 

 dular upper branches and peduncles; stem erect, 

 rather slender, i-3 tall, becoming somewhat 

 woody below. Leaves lanceolate or ovate-lanceo- 

 late, i '-6' long, acuminate at both ends, petioled, 

 their margins undulate, slightly crispecl,_ more or 

 less ciliolate ; ocreae cylindric, entire, brittle, soon 

 falling away; racemes panicled, sometimes gemi- 

 nate, i '-4' long, rather dense, erect; calyx lilac, 

 spicuously exserted ; stigmas black ; achene broadly 

 5-parted "to below the middle, the lobes petaloid; 

 stamens 6-8, included; style 2-parted, slender, con- 

 ovoid, lenticular, slightly gibbous on both sides, 

 long-pointed, black, granular, but somewhat shin- 

 ing, ii" long. 



In moist soil, southern Illinois, Missouri and Kansas 

 to Louisiana and New Mexico. Aug.-Oct. 



