POLYGONACEAE 



409 



reddish or rarely pale green, 5-6 mm. long; achenes included, 

 ovoid, trigonous, acute, yellow-brown, dull. Aug.-Oct. 



Wet grassy places in lowlands and mountains; Hokkaido, 

 Honshu, Shikoku, Kyushu; very common and variable; pos- 

 sibly this species hybridizes with No. 13. China, Korea, and 



Ussuri. 



15. Polygonum oreophilum (Makino) Ohwi. Polygo- 

 num thunbergii var. oreophilum Makino; Persicaria thunbcrgii 

 var. oreophila (Makino) Nemoto; Persicaria oreophila (Ma- 

 kino) Hiyama Yama-mizo-soba. Stems slender, elongate, 



diffuse, loosely branched, sparsely retrorse-prickly, the inter- 

 nodes elongate; leaves thinly hairy on both sides, hastate, 

 broadly ovate, truncate at base, the midlobe large, not con- 

 tracted at base, the lateral ones spreading, deltoid or ovate- 

 deltoid, acute or rather obtuse; petioles rather long, not 

 winged; inflorescence terminal and axillary; achenes gray, 

 lustrous. Mountains; Honshu. 



16. Polygonum bungeanum Turcz. Persicaria bunge- 



ana (Turcz.) Nakai; Polygonum chanetii Lev. Hari-tade. 



Annual; stems erect, branched, 20-60 cm. long, scantily short- 

 prickly; leaves lanceolate, 5-10 cm. long, 1-2.5 cm. wide, acute 

 to subobtuse, acute at base, short-pilose on the underside 

 especially on nerves, the petioles 5-12 mm. long; sheaths 3-8 

 mm. long, membranous, slightly pilose; spikes 2-5 cm. long, 

 very loosely flowered, the peduncles with stipitate glands; 

 flowers pale green, slightly red-tinged, about 3 mm. long, on 

 very short pedicels, the perianth-segments elliptic; achenes 

 subglobose, much inflated, biconvex, black, scarcely lustrous, 



about 2.5 mm. long and as wide. July-Sept. Sparsely 



naturalized in Honshu. Korea, China, Ussuri, and Man- 

 churia. 



17. Polygonum breviochreatum Makino. Persicaria 



breviochreata (Makino) Ohki; Persicaria ramosa Nakai 



Nagab.'V-no-ya-no-negusa. Slender annual, 30-50 cm. high; 

 stems elongate, branched, long-decumbent at the base, with 

 rather hairlike retrorse prickles; leaves thin, broadly lanceo- 

 late, 3-7 cm. long, 1-2 cm. wide, acute to acuminate, subobtuse 

 at tip, sagittate, green, glabrous, or scattered-strigose above, 

 often loosely stellate-pubescent beneath on lower leaves, the 

 basal lobules deltoid and obliquely deflexed, the petioles 2-10 

 mm. long, the sheaths tubular, slightly pilose, 3-4 mm. long, 

 long-ciliate; spikes terminal and lateral, remotely 1- to 3-flow- 

 ered, the peduncles short ascending-setose, often glandular; 

 flowers pale green with a pale reddish tinge, 3^ mm. long; 

 achenes broadly ovoid-ellipsoidal, inflated-trigonous, about 3 



mm. long, yellow-brown, lustrous. Aug.-Oct. Shaded 



grassy places in foothills; Honshu (Kanto Distr. and westw.), 

 Shikoku, Kyushu. Korea. 



18. Polygonum hastatoauriculatum Makino. P. auri- 

 culatum Makino, non Meissn.; Persicaria hastatoauriculata 



(Makino) Nakai Hosoba-no-unagi-tsukami. Annual; 



stems elongate, 30-80 cm. long, ascending or erect from long- 

 decumbent slender branching base, striate, with loose retrorse 

 prickles; lower leaves petiolate, the upper thinly chartaceous, 

 sessile to short-petiolate, hastate, lanceolate to narrowly so, 4-8 

 cm. long, 5-15 mm. wide, gradually narrowed above to an 

 obtuse tip, cordate, the lobules deflexed auriculate on each 

 side, the margin scabrous, the sheaths scarious, glabrous, 1-1.5 

 cm. long, often lobed on one side; spikes 1-3 cm. long, inter- 

 ruptedly 3- to 5-flovvered, the peduncles stipitate-glandular; 

 flowers reddish, 2.5-3 mm. long; achenes orbicular, inflated- 

 biconvex or obtusely trigonous, about 2 mm. long; achenes 



orbicular, inflated-biconvex, or obtusely trigonous, about 2 mm. 



long, pale, dull. Aug.-Nov. Wet places; Honshu (Kanto 



Distr. and west%v.), Shikoku, Kyushu. s. Korea and Ryu- 



kyus. 



19. Polygonum sieboldii Meissn. P. sagittatum sensu 

 auct. Japon., non L.; P. sagittatum var. sieboldii (Meissn.) 

 Maxim.; P. anguillanum Koidz.; Persicaria sieboldii (Meissn.) 



Ohki Unaci-tsukami. Glabrous annual; stems slender, 



angled, ascending to erect, decumbent and branched at the 

 base, often prominently retrorse-prickly, 20-100 cm. long; 

 leaves rather thin, broadly lanceolate or narrowly ovate-oblong, 

 4-8 cm. long, 1.5-3 cm. wide, obtuse to subacuminate and ob- 

 tuse at the tip, slightly glaucous, glabrous on both sides, 

 deeply cordate; stipules scarious, 5-10 mm. long, glabrous, 

 obhquely cut; spikes globose to ovoid-globose, densely flow- 

 ered, about 10 mm. long, the peduncles slender, glabrous, the 

 pedicels very short; flowers slightly reddish, 3-3.5 mm. long; 

 achenes obtusely trigonous, ovoid-globose, nearly lustreless, 



black, about 3 mm. long. June-Sept. Wet grassy places 



in lowlands. Hokkaido, Honshu. Korea, China, Man- 

 churia, and e. Siberia. 



Var. sericeum Nakai. Persicaria sieboldii var. tomentosa 



Hara Ke-aki-no-unagi-tsukami. Leaves and sometimes 



the peduncles pilose. Hokkaido, Honshu; rare. Korea. 



20. Polygonum hastatosagittatum Makino. Persicaria 

 hastatosagittata (Makino) Nakai; Polygonum strigosum var. 



hastatosagittatum (Makino) Steward. Nagaba-no-unagi- 



TsuKAMi. Annual; stems slender, elongate, from decumbent 

 branching base, 30-80 cm. long, scattered retrorse-prickly; 

 leaves narrowly ovate-oblong to lanceolate, subacuminate, 

 truncate to shallowly cordate at base, the lower corners (lobes) 

 rounded or deltoid to subhastate, the nerves beneadi retrorse- 

 prickly, antrorsely scabrous-setulose on upper margin, re- 

 trorsely so on lower margin, the petioles usually retrorse- 

 prickly, the sheaths scarious, tubular, 2-3.5 cm. long, truncate, 

 ciliolate; spikes globose to broadly ovoid, few toward the ends 

 of the branches, densely rather many-flowered, 1-1.5 cm. long, 

 the peduncles short-pubescent and glandular-pilose; flowers 

 about 3 mm. long, the pedicels 3-5 mm. long, often glandular- 

 pilose, longer than the bracts; achenes ovoid, trigonous, lus- 

 trous, deep brown, about 3 mm. long. Sept.-Oct. Wet 



grassy places in lowlands; Honshu, Kyushu; rather common. 



21. Polygonum nipponense Makino. P. hastatosagit- 

 tatum var. latifoliu?n Makino; Persicaria nipponensis (Ma- 

 kino) Gross Ya-no-negusa. Closely allied to the pre- 

 ceding; leaves broader, oblong to elliptic-ovate, abruptly acute, 

 5-8 cm. long, 2.5-4.5 cm. wide, truncate to shallowly cordate 

 at base without a distinct lobe on lower margin; flowers with 



pedicels 1-2 mm. long, shorter than the flowers. Sept.-Oct. 



Wet grassy places in lowlands; Hokkaido, Honshu, Shikoku, 

 Kyushu; common. Korea. 



22. Polygonum nepalense Meissn. P. alatum var. 

 nepalense (Meissn.) Hook, f.; Persicaria nepalensis (Meissn.) 

 Miyabe; Polygonum quadrifidum Hayata; P. lyratum Nakai 

 Tani-soba. Annual; stems branched and decumbent be- 

 low, 30-50 cm. long, glabrous, die nodes with fleshy retrorse 

 hairs; leaves petiolate or sessile, ovate-deltoid, gradually acute, 

 1.5-5 cm. long, 1-3 cm. wide, rounded to truncate and abruptly 

 decurrent on the winged petiole, scattered pilose and with a 

 yellowish sessile discoid gland beneath, glabrous above, the 

 sheaths thinly membranous, 4-8 mm. long, nearly nerveless; 

 spikes globose, terminal and axillary, densely flowered, with a 



