16 SCHEUCHZERIACEAE. 



25. ZANNICHELLIA. 



Submersed herbs; leaves small, linear; stems, flowers and leaf 

 buds at first enclosed in a hyaline envelope; flowers unisexual, in 

 axillary clusters, each composed of one staminate and 2-5 

 pistillate flowers; staminate flower with no perianth; pistillate 

 with a funnel-shaped undivided perianth; ovary flask-shaped 

 with a short style. 



Zannichellia palustris L. Stems slender, branching, leafy, 10-60 cm. long; 

 leaves thin, filiform, 1-nerved, 5-8 cm. long; fruit nearly sessile, flattened, 

 somewhat incurved, often more or less toothed on the back, 2-3 mm. long, 

 about twice as long as the style. In clear ponds and slow streams. 



Family 12. NAJADACEAE. 



Submersed aquatic herbs with slender branching stems; 

 leaves flat or filiform, opposite, alternate or whorled; flowers 

 monoecious or dioecious, axillary, solitary; staminate enclosed 

 in a membranous sheath; stamen 1, sessile or stalked with a 1-4 

 celled anther; ovary 1 with a short style, 1 -celled, 1-ovuled; endo- 

 sperm none. 



26. NAJAS. 



Characters of the family. 



Najas flexilis (Willd.) Rostk. & Schmidt. Stems slender; leaves numerous, 

 linear, acute or acuminate, 1-2 cm. long, minutely serrulate, the sheath broadly- 

 oblong; fruit 3 mm. long, oblong-linear, tipped with the persistent style; seed 

 pale-brown, shining. Near Viola, Idaho, Henderson. 



Family 13. SCHEUCHZERIACEAE. ARROW GRASS 



FAMILY. 



Swamp plants with narrow leaves and terminal racemose or 

 spike-like inflorescences; flowers perfect or unisexual, naked or 

 with a usually evanescent bract-like perianth; stamens 2 or 3; 

 carpels 3-6, each 1-2-ovuled, more or less united till maturity, 

 dehiscent or indehiscent. 



27. TRIGLOCHIN. ARROW GRASS. 



Flowers small, perfect, in terminal scapose, spike-like racemes; 

 perianth segments 3-6, greenish, evanescent; stamens 3-6; 

 anthers 2-celled, on very short filaments; carpels 3-6, united 

 into a compound pistil; ovules solitary; capsule, when ripe, 

 splitting into 3-6 carpels with a persistent central axis. 



Triglochin maritima L. Scapes subterete, 20-40 cm. high, exceeding the 

 leaves; leaves thickish, narrow; raceme elongate, 15^10 cm. long; fruit ovoid, 

 angled, 5-6 mm. long; carpels usually 6, sometimes 3. In salt marshes. 



