mm. long; staminodia 3, linear, obtuse; stigmas 3, bidentate, papillose. 



In ponds and sloughs in Ariz. (Coconino Co.), May-Oct.; apparently endemic. 



2. Elodea longivaginata St. John. Fig. 74. 



Stems elongate, slender, sparingly dichotomously branched; middle and upper 

 leaves opposite or occasionally with at least some in whorls of 3, linear, rounded 

 to broadly obtuse at apex, finely serrulate especially near and at the tip, the longer 

 ones 1.5-2.6 cm. long and 1-2.5 mm. wide, bright green and flaccid, scarcely 

 imbricate; staminate spathe short- to long-pedunculate, 6-10 mm. long, 1 -flowered; 

 flower with an elongate threadlike hypanthium to about 3 dm. long, with sepals 

 about 4 mm. long and petals 5 mm. long; stamens 9, all attached at the summit of 

 the hypanthium; pistillate spathe (and stalk) 3-7 cm. long, the flower with a 

 threadlike hypanthium that elongates to about 3 dm. long so as to bear the flower 

 to the surface of the water; sepals 2.8 mm. long and petals 4 mm. long; staminodia 



3. ligulate; stigmas 3, oblong, undivided; capsule about 1 cm. long; seeds cylindric, 

 6 mm. long. 



Submersed in water of lakes, ponds, sloughs and quiet running water in N.M. 

 (Mora, Rio Arriba and San Miguel cos.), June-Oct.; from Alta. to N. D., s. to 

 Mont., Wyo., Colo., N. M. and Ut. 



.3. Elodea canadensis Rich, in Michx. Fig. 73. 



Stems elongate, slender dichotomously branched; middle and upper leaves in 

 whorls of 3, linear to lance-oblong, mostly 8-15 mm. long and 1.5-3 mm. wide, 

 rarely larger, bright green, thin, flaccid, finely serrulate, strongly imbricate at tip 

 of stems (especially in pistillate plants); staminate spathe with a narrowed pedun- 

 culate base, inflated, ellipsoid to ovoid, 7 mm. long and 4 mm. wide; flowers 

 peduncled by the slender threadlike elongate base of hypanthium, with the sepals 

 3.5-5 mm. long and petals 5 mm. long; stamens 9, with the 3 inner ones raised 

 on a common fused stalk; pistillate spathe cylindric; flowers exserted from the 

 spathe by the threadlike elongate base of the hypanthium which is to 15 cm. 

 long; sepals and petals 2-3 mm. long; staminodia 3, acicular; stigmas 3, 4 mm. 

 long, broad, 2-cleft at apex; capsule ovoid, 6 mm. long; seeds narrowly cylindric, 

 4.5 mm. long, glabrous. Anacharis canadensis (Rich, in Michx.) Rich. 



In lakes, ponds and slow-moving streams, especially in calcareous areas, re- 

 ported (but not seen) from Okla., in N. M. (Sandoval and Taos cos.) and Ariz. 

 (Coconino and Navajo cos.), June-Oct.; from Que. to Sask., s. to Va., Ala., (?) 

 Okla., N. M., Ariz, and Calif.; also introd. in Eur. 



4. Elodea NuttaUu (Planch.) St. John. Fig. 74. 



Stems slender, dichotomously branched, often freely so; middle and upper leaves 

 in whorls of 3 or occasionally with some in 4's, linear to narrowly lance-linear, 

 6-13 mm. long, 0.3-1.5 mm. wide, rarely more, acute at apex, green and flaccid, 

 finely serrulate; staminate spathe borne at the median axils, sessile, ovoid, apicu- 

 late, 2-parted to well below the middle, the 2 acuminate teeth often twisted to 

 form the apiculate tip, the body 2 mm. long; flower single in each spathe, sessile, 

 at maturity breaking loose to float to the surface and there opening; sepals about 

 2 mm. long and 1.6 mm. wide; petals usually wanting or (when occasionally 

 present) 0.5 mm. long; stamens 9, the 3 central ones slightly elevated on a com- 

 mon stalk, the 6 outer ones at a lower level and with separate filaments; pistillate 

 spathe narrowly cylindric, somewhat ovoid at base, usually 1-1.5 cm. long; flower 

 stalked by a slender threadlike elongated hypanthium as much as 9 cm. in length; 

 sepals 1.1 mm. long and petals 1.3 mm. long; staminodia 3, 0.5 mm. long, 

 acicular; stigmas 3, slender, bifid, somewhat exceeding the sepals; capsule sessile, 

 narrowly ovoid to fusiform, 5-7 mm. long, 1.5-2 mm. in diameter; seeds cylindric, 

 short-beaked, 3.5-4.5 mm. long, pilose. Anacharis Nuttallii Planch., A. occidentalis 

 (Pursh) Marie- Vict. 



165 



