PIPER FLORA OF THE STATE OF* WASHINGTON. 227 



Fruiting pedicels erect. 



Stout; akenes dull II. P. ramosissimum. 



Slender; akenes smooth, 



shining 12. P. satvatchense. 



Fruiting pedicels reflexed. 

 Flowers campanulate, 2 



to 3 mm. long 13. P. douglasii. ' 



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. spergulariaeforme. 



Style 3-parted; filaments 



dilated Ki. P. nuttallii. 



Blades of the leaves not jointed on the pedicels. 



Segments of the ocreae rigid 17. P. greenei. 



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



Leaves comparatively large; flowers mainly terminal. 

 Perennials. 



Styles 3; plants with thick roots. 



Flowers in a single dense spike-like raceme; 

 styles long. 



Raceme thick not bulbiferous; akenes 



smooth 19. P. histortoides. 



Raceme slender, often bulbiferous ; akenes 



dull 20. P. vivi'parum. 



Flowers in racemes or panicles; styles short; 

 alpine plants. 



Racemes mainly axillary; leaves pubes- 

 cent 21. P. Tiewherryi. 



Racemes panicled. 



; Leaves ovate; akene ovoid 22. P. plnjlolaccaefolium 



\ Leaves lanceolate; akene obovoid . 23. P. alpinum. 



\ Styles 2; aquatic or swamp plants with flowers in 



t spike-like racemes. 



Ocreae fringed at the spreading summit 24. P. hartunnghtii. 



t Ocreae not fringed nor spreading. 



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



Leaves ovate, acuminate 26. P. emersum. 



Annuals; flowers in several spike-like racemes. 



Styles 3-cleft; akenes 3-angled 27. P. hydropiperoides. 



Styles 2-cleft; akenes lenticular. 



Ocreae naked; racemes drooping. 



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



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



Ocreae bristly-ciliate. 



Calyx not glandular; raceme dense 30. P. pej-.ncaria. 



Calyx glandular; racemes interrupted. 



Racemes erect - - - - 31 . 7-^. punctaium. 



Racemes drooping 32. P. hydropiper. 



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

 Polygonum scandens L. Sp. PI. 1 : 364. 1753. 

 Type locality: "Habitat in America." 



