666 PONTEDERIACE^E xerophyllum 



HETERANTHERA 



2 or 3, short: raceme loose, becoming 3-15 inches long, 30-40-flowered : 

 pedicels 3-6 lines long, twice longer than the linear-lanceolate bracts and 

 bractlets : segments of the perianth 3-4 linfs long, a third longer than the 

 stamens, bright yellow : filaments woolly except near the top : capsule ex- 

 serted, the cells 10-15-seeded. In marshes in the Coast Mountains, south- 

 ern Oregon and northern California. 



6 XEROPHYLLUM Michx. Fl. i, 210. (1803.) 



Tall perennial herbs with thick short woody rootstocks, coarse 

 fibrous roots, simple erect leafy stems, narrow linear serrulate 

 persistent leaves and many small white flowers in a terminal ra- 

 ceme. Perianth of 6 distinct several-nerved persistent segments. 

 Stamens 6, inserted at the base of the segments, with filiform- 

 subulate filaments and rounded extrorse laterally dehiscent an- 

 thers. Ovary sessile, ovate, 3-lobed, with 1-2 pairs of ovules in 

 each cell. Capsule chartaceous, loculicidally dehiscent to the 

 base, and sometimes also septicidal. Seeds 2-4 in each cell, as- 

 cending, oblong, somewhat triangular-flattened, with thin longi- 

 tudinally wrinkled, rather light-colored testa. 



X. tenax Nutt. Gen. i, 235. Rootstock often an inch thick or more: 

 stems stout, 2-6 feet high, leafy below: radical leaves numerous, 1-3 feet 

 long, about 2 lines wide, flat above, rather rigid ; cauline leaves shorter, 

 scattered, gradually reduced udward : racemes at first dense, elongating 

 and becoming 1-2 feet long : lower bracts foliaceous and serrulate, the up- 

 per scarious and oflen upon the lower part of the pedicel : pedicels an inch 

 or two long, erect in fruit : segments of the perianth 4-5 lines long, scarcely 

 equalling the stamens : styles 2 lines long : capsule broadly ovate, acute, 

 nearly 3 lines long, 3-valved : seeds narrowly oblong. Common in the high 

 mountains, California to Brit. Columbia and Idaho. 



X. Douglasii Watson Proc. Am. Acad, xiv, 284. " Pedicels shorter, 

 (6-15 lines long) : flowers smaller, the segments (2% lines long) exceeding 

 the stamens : styles a line long : capsule cordate-ovate, 2 lines long, 6-valved, 

 the abruptly acute cells separating and then dehiscing: seeds snorter and 

 broader. Oregon to Montana. " 



Order XCIX PONTEDERIACE^ Dumort. Fam. 59. (1829) 



Perennial aquatic or bog plants with grass-like or petioled 

 thick leaves and perfect more or less irregular solitary or spiked 

 flowers subtended by le^f-like spathes, Perianth free from the 

 ovary, corolla-like, 6-parted. Stamens 3 or 6, inserted on the 

 tube or the base of the perianth: filaments filiform, dilated at 

 base or thickened at the middle: anthers 2-celled, linear-oblong 

 or rarely ovate. Ovary 3-celled with the placentae in the axis, 

 or 1-celled with 3 parietal placentae. Style filiform or columnar, 

 with terminal entire or minutely toothed stigma, ovules ana- 

 tropous, numerous, sometimes only one of them perfect. Fruit 

 a many-seeded capsule or 1-seeded utricle. Embryo central, 

 cylindrical, in copious albumen. 



1 HETERANTHERA R. & P, Prodr. Fl. Per. 9. (1791.) 



Herbs with creeping, ascending or floating stems, grass-like or 

 petioled leaves and small yellow, white or blue flowers subtended 



