POLYGONACEAE (BUCKWHEAT FAMILY) 155 



about 2 mm. long. — Introduced everywhere in the east, and to some extent 

 in our range. 



11. Rumex persicarioides L. 1. c. Annual, simple, or diffusely branched, 

 the low stems erect qr procumbent, ininutely pubescent; , leaves linear- 

 lanceolate, usually truncate or cordate at base, 3-10 cm. long, mostly on 

 short petioles, sogiewhat wavy-margined: flowers in numerous dense verticils 

 along the slender branches: valves pyate-lanoeolate, with 2 or 3 long-awned 

 teeth on each side, all grain-bearing. B. maritima. — ^Mostly in saline soils; 

 transcoiitinental. \ ,' ',/ ' ' 



12. Rumex densiflorus Osterli^ Erythea 6: 13. 1898. Stout erect glabrous 

 scarcely branched perennial, from thick horizontal rootstocks; stems clustered, 

 grooved, :.5-10., dm. high: lower leaves very large, 1.5-3 dm. long, 10-15 cm. 

 wide, usually very ''obtuse, long-petioled; upper leaves gradually reduced: 

 flojvers in dense clusters, terminating the-stem and its branches^ polygamous 

 or dioecious: calyx usually red; the anthers broWn: Valves naked; the wings 

 broadly ovate, shorter than the pedicels: achene ash-color. — Stream banks at 

 high elevations; Colorado and Wyoming. i ' , 



13. Rtjmex polyrrjiizus Greene, Pitt. 4: 305. 1901. Slender sparingly leafy 

 perennial, 5-10 dm.'high: stem solitary from a short vertical crown surmount- 

 ing a small fascicle of fleshy roots, usually a whorl of fibrous roots near summit 

 of crown: leaves from lanceolate to linear, 12^20 cm. long, on petioles usually 

 shorter than the blade, flat or crisped near the base: panicle strict but rather 

 loose; pedicels slightly enlarged upward, jointed well above the base: valves 

 thin^ venulose, the rfilargin obscurely crenate-dentate. {R. Bakeri, Greene, PI. 

 Baker. 3: 15. 1901; iJ. proecoa; Rydb. Bull. Torr. Bot. Club 33: 137. 1906.)— 

 Wet mountain meadows; Colorado and Montana. 



14. Rumex ocddfetitalis Wats. Proc. Am. Acad. 12: 253. 1876. Mostly 

 6-9 dm. high, rather stout, subsimple: leaves somewhat fleshy, glabrous, 

 glossy, biluish-greenJJTwavy margined, the lower very large, ovate or mostly 

 oblong-6v'ate, truncately cordate, the apex rounded to subacute: panicle strict, 

 dense and rosy in fruit, naked or with a few small leaves below; whorfs some- 

 what.remote but overlapping; pedicels 2 to 3 times as long as the fruit: valves 

 sometimes rosy, i-€'\aTa. long, deltoid-ovate, often only shghtly cordate, re- 

 motely erose or denticulate, rounded or obtuse at apex, without callosities. 

 [R. subalpina Jones; : Proc. Cal. Acad. 11. 5: 720. 1895.] — ^Texas to Ontario 

 and California. 



■>';,y,^, ;;;.,: ;„ ,4. POLYGONUM L. , Knotweed 



Terrestrial, aniphibious, or aquatic herbaceous (ours) annuals or pereimials 

 with fibrous roots, of ""tuberous or thickened rootstocks. Stem simple or 

 branched, more or less swollen at the numerous nodes, erect, prostrate or 

 climbing.i Leaves alternate and entire; sheaths truncate or oblique at sum- 

 mit, "lobed, lacerate, or fringed. Flowers axillary-racemose or. spicate; pedi- 

 ,Gels jointed. CalyX mostly 5-parted, the divisions often petal-lite, all erect 

 in fruit, persistent. Stamens 4^9. Styles or stigmas 2 or 3; achene accord- 

 ingly lenticulate or 3-angular. ' 



' ■ ' Key to the Sections 



Flowers in terminal spikes; withscarious bracts; ,fila-^ 



ments filiform. ^ ,^,., 



' RootsdUberous, or fleshy'rhiioiaes . . . . I. BISTORTA. - 

 ; Roots fibrous; . . ; >! 'i ; . . . 11. PERSICAKIA. 

 Flowers axillary, or racemose with foliar bracts. 



. Stems mjtcjunbing , . - HI. AVICULARIA. 



"item^3imbing .■■'. '; ' . . . IV. BILDERDYKU (TIHIAIUA). 



BIST0RTA.7rrPereimials of northern or subalpine distri)}Ution. 



Rootstpok elongated; ispike floriferous throughout . . 1. P. bistOTtoides. 

 'ftootsiocfccorm-likeV Spike bearing bulblets . . . . 2. P. nviparum. 

 .PERSICARIA.— Annuals or perennials, mostly of southern and 

 ' n !of middle to lower altitudes. , 



