POLYGONACE^. (BUCKWHEAT FAMILY.) .311) 



4- -»- Branches slender and virgate, angled, terminating in more or less open spikes, 

 the narrow leaves diminishing upward and hecominff bract-iike. 



3. P. ramosissimum, Michx. Erect or ascending, usualli/ 2 to 4 feet 

 high, often braucliing only above, glabrous, the whole plant t/dlowish : shialhs 

 loose, becoming lacerate to the base: leaves lunceolato to linear: (lowerrt and 

 fruit as in P. erectum, the sepals more frequently G, st<imeus 3 to G, and akt-no 

 usually smooth and shining. — From the JSierra Nevada eastward atross the 

 continent. 



4. P. tenue, ^lichx. Erect and slender, ^ to l^fat high, glabrous and 

 somewhat glaucous, sometimes slightlg scabrous at thevodes: shtaths with a close 

 somewhat herbaceous base, sparinglij scarious and lacerate al>0Le: loavej« linear to 

 lanceolate, usually much reduced above : flowers often solitary and unually dis- 

 tant, soon reflexed, the sepals margined with white or rose-color: stamtns 8: 

 akenes ovate, black and shining. — From Arizona to British Columbia nnd 

 eastward across the continent. The following varieties occur in the Uocky 

 Mountains : — 



Var. latifolium, Engelm. With broader leaves and more numoruus 

 flowers. 



Var. mierospermum, Engelm. A low slender form, with minute flowers 

 and fruit. 



* * Low and slender: flowers in short dense spikes, with imbricated bracts : sepals 



colored: leaves linear. 



5. P. imbricatum, Xutt. Stem l to 8 inches high, smooth or slightly 

 scabrous at the nodes, often diffusely branched : sheaths rather large. 2 j)arted 

 or lacerate above the short scarious base : bracts with sometimes a scarious 

 m:irgiu : flowers nearly sessile, rose-colored or white : stamens 3 or 5 : akeuc 

 minutely tuberculate striate or smoothish. — Alpine and subalj)ine, from Colo- 

 rado to California and Oregon. It has usually been referred to P. c(xirctatum. 



§ 2. Flowers fascicled, in usuallg dense spikes, icith small scarious bracts: Uares 

 not jointed on the petiole: sheaths cylindrical and truncate, scarious, entire, 

 naked or ciliate-fringed or margined: perianth colored, h-parted, apprcs>cd to 

 the lenticular or triangular akene : stamens 4 to S; fllaments fllij'urm. — 

 Persicaria. 



* Sheaths and bracts not ciliate nor fringed: sepals not punctate: style 2-clffl, 



and akene flattened or lenticular. 



6. P. Pennsylvanicum, L. Stem l to 3 fed high, smooth l)elow, the 

 branches above and especially the peduncles beset irith bristly-stalktd glands: 

 leaves lanceolate, roughish on the midrib and margins : sju'krs oblung, ol>tuse, 

 erect, thick: flowers bright rose-color: stamens mostly 8, somewhat exserted. — 

 Colorado and eastward to the Atlantic States. 



7. P. inearnatum, Ell. Stem 3 to efeet high, nearly glabrous, the pedun- 

 cles, etc. often minutely rough with scattered sessile glands: leaves rough on 

 the margins and midrib, elongated-lanceolate : spikes linear, nodding, btt»ming 

 slender: flowers smaller than in the last, lighter rose-color shading to white: 

 stamens 6 and styles 2, both included. — Colorado and e:istward to the Atlantic 

 States. 



8 P. lapathifolium, Ait., var. incanura, Koch. Lourr, with shorter 

 and less pointed leaves, which are lanceolate, obtuse, and white-downif beneath: 



