BUCKWHEAT FAMILY. 137 



Flowers in axillary clusters, either widely separated or crowded into a terminal spike- 

 like raceme, with foliaceous bracts; stamens mostly 8, the filaments or some of them 

 often dilated at the base; achene triangular; leaves mostly narrow and lanceolate or 

 linear, jointed upon a very short petiole adnate to the short sheath of the scarious 

 stipules. — Subgenus Avictlaria. 

 Perennial and more or less suffrutescent. 



Flowers several in a cluster, crowded at the ends of the branches; stipules con- 

 spicuously lacerate; leaves revolute 1. P. paronychia. 



Flowers 1 or 2 in each axil, less crowded; stipules 2-lobed, the lower lobe lacerate; 



leaves plane 2. P. bolanderi. 



Annuals. 



Prostrate; branches leafy to the ends 3. P. avicularc. 



Erect; leaves diminishing upwards and becoming bract-like, the branches terminating 



in more or less loose spikes 4. P. spcrgulariaeforme. 



Flowers spicate, solitary in the axils, the internodes very short; stamens 8; achene 

 triangular; leaves very narrow, not jointed to the lacerate stipule; ours slender wiry 

 brittle annuals. — Subgenus DvRAVIA. 



Plants 3 to 7 in. high; rlowers in terminal or axillary spikes 5. P.californicum. 



Plants 1 to 2 in. high, flowering even from the base; leaves 1 to 2 lines long 



6. P. parry i. 

 Flowers in dense spike-like racemes (usually geminate or paniculate), with small scari- 

 ous bracts; calyx 5-parted, appressed to the triangular or lenticular achene; stamens 

 4 to 8, filaments filiform; leaves ample, not jointed to the petiole. — Subgenus 

 Persicaria. 

 Spikes solitary or sometimes 2; flowers red; stamens 5, exserted; achene lenticular; 

 mostly aquatic perennials. 



Leaves mostly elliptical or oblong; spikes oblong or ovate, l / 2 to 1 in. long 



7. P. amphibiutn. 



Leaves ovate-lanceolate; spikes more elongated, 1 to 3 in. long 8. P. muhlenbcrgii. 



Spikes several to many, geminate or more or less paniculate; stamens 6 to 8, included; 

 achene either lenticular or triangular. 

 Sheathing stipules naked in age; spikes often drooping; sepals white or flesh-color; 



stamens 6; annual 9. P. lapathifolium. 



Sheathing stipules fringed with bristles; spikes erect. 



Sepals pink, red or greenish; spikes not interrupted; stamens generally 6; annual. 



10. P. persicaria. 

 Sepals greenish and glandular-dotted; spikes interrupted; stamens 8; perennial of 



marshy places 11. P. punctatum. 



Flowers in loose panicled racemes; stamens 8; achene triangular; leaves cordate; 

 twining plants. — Subgenus Tiniaria. 

 Annual 12. P. convolvulus. 



1. P. paronychia C. & S. Stems from large woody rootstocks, suffrutes- 

 cent, prostrate or ascending, 1 to 3 ft. long; branches leafy above, below 

 clothed with old sheaths; sheaths large, 4 to 6 lines long, brown and 5-nerved, 

 the margin freely lacerate above, persistent, the segments becoming hair-like 

 in age; leaves linear-lanceolate, 5 to 8 (or 11) lines long, acute, the margin 

 revolute; flowers about 3 in an axil, on short pedicels, densely crowded at the 

 ends of the branches in short, more or less leafy spikes; sepals white or rose- 

 color, oblong-ovate, 3 lines long; stameiis 8. 



.Sandy hills near the coast: San Francisco and northward. Sepals centrally 

 and pinnately green-veined, the pinnae tooth-like. 



2. P. bolanderi Brewer. Stems many, erect, suffrutescent below or aris- 

 ing from a woody taproot, 5 to 10 in. high; sheathing stipules scarious, 2- 

 lobed, the lower lobe finely lacerate, persistent; leaves narrowly linear to sului- 

 late, acute or cuspidate, 2 or 3 lines long, not revolute; flowers 1 or 2 in the 

 axils on the branchlets, involucrate with a sheath-like scarious bract on the joint 

 of the very short pedicel, 1% lines long; calyx 5-parted; sepals white or 

 rose-color, with a green midrib, oblong-ovate, slightly spreading; stamens 

 8 or 9, included. 



Rocky outcroppings, exact localities known only in tin- Napa and Mt. Eood 

 ranges. July-Sept. 



