3. Triglochin debilis (M.E. Jones) Love & Love. 



Plant slender, 1-3 dm. tall, usually well-spaced and erect-spreading from a 

 slender elongate rootstock, the base covered with coarse brownish fibers of the 

 leaf bases, the rootstock with conspicuous internodes and bracteate nodes; leaves 

 8-20 cm. long, the sheaths membranous-margined, terminating above in a 2-lobed 

 ligule 0.5-1 mm. long; scapes longer than the leaves, terminated by a strict 

 raceme, the rachis may be either straight or fractiflex; pedicels slender; flower 

 with 6 perianthlike appendages each bearing an attached anther; mature fruit 

 composed of 6 united carpels about 3-3.5 mm. long and 1-2 mm. thick, usually 

 all fertile; fruiting carpels separating readily from the slender carpophore, inde- 

 hiscent; seeds slender, needlelike. T. concinnum Davy var. debilis (M.E. Jones) 

 J. T. Howell. 



In wet meadows and marshes along streams, in brackish to saline or alkaline 

 situations, in Ariz. (Coconino and Navajo cos.), May-Oct.; from Ore. to Calif., 

 e. to and beyond the Rocky Mts., from N. D. to Colo, and Ariz. 



Fam. 21. Alismataceae Vent. Water Plantain Family 



Annual or perennial lacticiferous aquatic or marsh plants with fibrous roots 

 from a usually somewhat thickened rootstock and a cluster of basal leaves with 

 their long petioles sheathing a scape; leaves at first typically bladeless but soon 

 developing either a linear or sagittate type of blade with prominent nerves and 

 transverse veinlets; scape erect or arching, with a simple or branched bracteate 

 inflorescence; flowers perfect or unisexual, regular, borne in verticils; perianth 

 segments imbricate or involute in bud; sepals 3, green, persistent; petals 3, decidu- 

 ous; stamens 6 to many, included, the filaments distinct, the anthers 2-celled and 

 dehiscing by longitudinal slits; carpels numerous, distinct, 1-celled and mostly 

 1-ovuled, arranged in a ring or crowded on a receptable to produce a headlike 

 fruit of flat or turgid achenes that are usually provided with resin ducts and/ or 

 wings. 



A family of about 13 genera and 90 species of worldwide distribution. 



Species that comprise this family are known to attract marsh and song birds 

 and to provide shade and shelter for young fish, while the tubers formed by many 

 species, as well as the achenes, are eaten by wildfowl. Mammals, such as muskrats, 

 beavers and porcupines, are known to eat the vegetative parts of many species of 

 Sagittaria. 



Seeds of most of our species are ideafly suited for dissemination by birds and 

 animals in that the beak formed by the style can readily become hooked in 

 feathers and furs, and even to minute particles of soil that may remain on muddy 

 feet. Also, the resin ducts and suberous wings and excrescences of the achenes 

 of many species enable them to float great distances. 



1. Achenes arranged in a single ring on the receptacle, strongly flattened; 

 stamens 6 1. Alisma 



1. Achenes densely crowded over the surface of the receptacle; stamens more 



than 6 (2) 



2(1). Flowers all perfect; achenes plump; fruiting heads simulating a bur 



2. Echinodorus 



2. Flowers perfect or unisexual, the upper ones mostly staminate; achenes flat- 



tened; fruiting heads not burlike 3. Sagittaria 



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