BUCKWHEAT FAMILY 233 



Fruit erect. 



Inflorescence of small axillary clusters scattered more or less thoroughout the plant; 



all except P. minimum with elongated stems or branches; perianth-lobes never 



keeled near the apex. 

 Plants copiously leafy throughout; upper leaves scarcely reduced and more 



crowded. 

 Very slender and low annuals, with red wiry, terete, non-stnate stems. 



1. P. minimitm. 



Stouter and larger plants, often perennial, with prominently striate stems, 



usually 3-8 dm. long. 

 Perianth-lobes with yellowish green margins; plant erect, with spreading 



branches in age; leaves broad, yellowish green. 2. P. erectum. 

 Perianth-lobes with white, pink or purplish margins; plant prostrate or 

 diffusely spreading; leaves from bright to pale bluish green. • 

 Leaves thick, prominently veined, oblong, oval, or spatulate, obtuse or 

 roimded at the apex, usually pale; ocreae very conspicuous; 

 faces of the achene^s granular. 3. P. buxiforme. 



Leaves thin, not prominently veined, bright green; ocreae not conspicu- 

 ous; faces of the achenes finely striate. 

 Perianth 2.5-3.5 mm. long; achenes 2.5-3 mm. long, acute; leaves 



2-4 cm. long. 4. P. aviculare. 



Perianth 2-2.5 mm. long; achenes 2-2.5 mm. long, acuminate; leaves 

 mostly less than 2 cm. long. 5. P. negkctum. 



Plants with the upper leaves more scattered and reduced; mostly erect perenmals. 

 Upper bracts not subulate; achenes mostly dull. 



Lobes of the perianth with yellowish margins; perianth 3-4 mm. long; 



achenes about 3 nun. long, nearly smooth. 6. P. ramosissimum. 



Lobes of the perianth with whitish or pinkish margins; perianth 2-3 mm. 



long; achenes 2-2.5 mm. long, distinctly granulate or striate. 

 Plant copiously branched and broom-like; leaf-blades Unear or nearly 



so; achenes granulate. 7. F. prohpcurn. 



Plant sparingly branched, mostly below; leaf-blades oblanceolate 

 eUiptic; achenes flnelv striate. . 8. P. rubescens. 



Upper bracts subulate; achenes smooth and shining. 9. P. sawatchense. 



Inflorescence aggregate at the ends of the branches, or more scattered in P. parony- 

 chioides, in which, however, some of the perianth-lobes are keeled near the 

 apex; bracts leaf-Ukeand usually broader than the narrowly Unear leaves ; plants 



d warf annuals. 



Perianth-lobes not keeled. . , ^ i j a 



Leaves several, gradually mergmg into the bracts; achenes blunt-angled and 



strongly striate. 10. P- ^^^somi. 



Leaf usually solitary and much longer than the bracts; achenes sharp-angiea 

 and obscurely striate. • H- P- umfolium. 



Some of the perianth-lobes keeled near the apex. 



Bracts herbaceous or the uppermost with a very narrow scanous margin. 



Bracts linear; ocreae conspicuous; inflorescence interrupted. . . .^ « 



12. P. paronychiotaes. 



Bracts oblong or narrowly oblong; ocreae inconspicuous; inflorescence con- 

 tiguous and dense. 13- P- ^f ^^<^fjv. 

 Bracts with broad white petaloid margms. 14. P. polygacotaes. 



Fruit reflexed. 



Upper bracts much reduced and subulate. t™^««v,- 



Perianth 1.5-2.5 mm. long; leaves narrowly Unear. 15. P. ±.ngelmanmi. 



Perianth 3-5 mm. long. , , i- u ^^ ^u^ 



Outer perianth-lobes oblong, obtusish, thickened and green or purphsh on the 

 back; lower leaves oblanceolate to linear-oblanceolate. . 



16. P- Douglastx, 



Outer perianth-lobes obovate, rounded at the apex, merely with a narrow 



midrib; lower leaves linear. , , . . 



Inflorescence long, lax, virgate; ocreae of the bracts inconspicuous. 



17. P. majus. 



Inflorescence dense, crowded at the ends of the branches; ocreae of Uie 

 bracts contiguous and conspicuous. 18. P. spergulanforme. 



Upper bracts foliaceous, relatively broad lanceolate or oblong. 



Perianth 3.5-4 mm. long; lower leaves oblong or nearly so. , « 



Achenes included. 19- P- montanunu 



Achenes exserted. 20. P. commixtum. 



Perianth 2-2.5 mm. long; lower leaves obovate, very acute. stinae 



k 



1. P. minimum S. Wats. Annual; stem erect or spreading, 3-20 cm., 

 rarely 30 cm. high, branched mostly at the base; leaves obovate, sometimes 

 ovate or elliptic, 0.5-2 cm. long, evenly distributed or crowded above; perianth- 

 segments 1.5-2 mm. long, greenish with rose-colored margms; achenes 2-2.6 

 mm. long, smooth and shining. P. Torreyi S. Wats. Dry or sandy slopes: 

 B.C.— Mont.— Colo.— CaUf. Suhmont. Jl-S. 



2. P. erectum L. Annual; stem usually erect, 2-6 dm. high, yeUowish 

 green; leaves oval, elliptic or obovate, 1-6 cm. long; flowers m small axillary 



