PIPER FLORA OF THE STATE OF WASHINGTON. 227 



Fruiting pedicels erect. 



Stout; akeiies dull II. P. raiiin.sissinniin. 



Slender; akenes smooth, 



shining 12. F. .mwakhense. 



Fruiting pedicels reflexed. 

 Flowers campanulate, 2 



to 3 mm. long 13. P. dougJasii. 



Flowers funnel-form, 



3.5 to 4.5 mm. long. . 14. P. majus. 

 Flowers in interrupted, but rather 

 close spikes. 



Style 3-cleft; filaments slen- 

 der 15. P. s-pen/uhirt<i(^orine. 



Style 3-parted; filaments 



dilated 16. P. nuttallii. 



Blades of the leaves not jointed on the pedicels. 



Segments of the ocreae rigid 17. P. (jreenei. 



Segments of the ocreae not rigid 18. P. parnji. 



Leaves comparatively large: flowers niainh- terminal. 

 Perennials. 



Styles 3: plants with thick roots. 



Flowers in a single dense spike-like raceme; 

 styles long. 



Raceme thick not l)ulhiferous; akenes 



smooth 19. P. lii.'^lorfoide.'^. 



Raceme slender, often l)ull)iferous; akenes / 



dull 20. P. rlrijxinnn. 



Flowers in racemes or panicles: styles short; 

 alpine plants. 



Racemes mainly axillary; leaves pubes- 

 cent 21. P. ntirheiTtji. 



Racemes panicled. 



Leaves ovate; akene ovoid 22. P. j)/i [itoluccacfoHiim 



Leaves lanceolate; akene obovoid. .. . 23. P. ul/ilnum. 

 Styles 2; acjuatic or swamp plants with flowers in 

 spike-like racemes. 



Ocreae fringed at tiie spreading summit 24. P. liaitirrUihtH. 



Ocreae not fringed nor spreading. 



Leaves oblong-elliptic, obtuse 25. P. ainpliibium. 



Leaves ovate, acuminate 2(). P. einersunt. 



Annuals; flowers in several spike-like racemes. 



Styles 3-cleft; akenes 3-angled 27. P. Iii/dtvjiiprroides. 



Styles 2-cleft; akenes lenticular. 



Ocreae naked; racemes drooping. 



Akenes broad; style 2-cleft 28. P. JapatJnfolium. 



Akenes narrow; style 2-parted 29. P. incarnatum. 



Ocreae bristly-ciliate. 



Calyx not glandular; raceme dense Zi). P. p>'r.'<icavia. 



Calyx glandular; racemes interrupted. 



Racemes erect 31. P. jmndatum. 



Racemes drooping 32. P. hydropiper. 



1. Polygonum dumetoruni scandens (L.) Gray, Man. cd. 5. 418. 1867. 

 Polij<jonuiii scaitdens h. Sp. PI. 1: 3t)4. 1753. 

 Type locality: "Habitat in America." 



