38 GRAMINEAE (GRASS FAMILY) 



3. Sagittaria longiloba Engelm. in Torr. Bot. Mex. Bound. 212. 1859. 

 Glabrous: petioles and scapes rather long and slender: leaves with short 

 lanceolate blade and usually very long linear-lanceolate acute lobes, 2-3 times 

 as long as the blade: bracts lanceolate, acuminate: stamens numerous; the 

 filaments longer than the anthers: achene quadrate-obovate, winged all 

 around, beak wanting or nearly so. Nebraska and Colorado to Mexico. 



4. Sagittaria latifolia Willd. Sp. PL 4: 409. 1806. Monoecious, as are all of 

 ours, glabrous or nearly so, 2-10 dm. high: leaves broad and abruptly con- 

 tracted to the acute apex; basal lobes usually broad, divergent and often 

 slightly out-curved, about half as long as the blade: bracts acute or obtuse: 

 flowers rather large, 2-3 cm. broad: achene with broad wing on either side 

 narrowed into the nearly horizontal slender beak, one third as long as the 

 body. Very variable; throughout North America; infrequent in our range. 



15. HYDROCHARITACEAE Aschers. TAPE GRASS FAMILY 



Represented in our range by a single genus, which see for characters. 



PHILOTRIA Raf. WATERWEED 



Perennial slender submerged herbs, with elongated branching stems 

 thickly beset with pellucid and veinless, 1-nerved, sessile, whorled or opposite 

 leaves. The staminate flowers (rarely seen) commonly break off, as in Vallis- 

 neria, and float on the surface, where they expand and shed their pollen 

 around the stigmas of the fertile flowers, raised to the surface by the pro- 

 longed calyx-tube. (Elodea Michx.) 



1. Philotria canadensis (Michx.) Brit. Science II. 2: 5. 1895. Leaves in 

 threes or fours, or the lower opposite, varying from linear to oval-oblong, mi- 

 nutely serrulate: stamens 9 in the sterile flowers, 3-6 almost sessile anthers in 

 the fertile. [P. angustifolia (Muhl.) Brit, and P. minor (Engelm.) Small.] 

 Slow streams and ponds, common; widely distributed in North America; 

 rather rare in our range. 



16. GRAMINEAE Juss. GRASS FAMILY 



Annual or perennial herbs of various habit, rarely shrubs or trees. Stems 

 (culms) generally hollow or sometimes solid, the nodes closed. Leaves sheath- 

 ing, the sheaths usually split to the base on the side opposite the blade, a 

 scarious or cartilaginous ring (ligule) borne at the base of the leaf-blade. 

 Inflorescence spicate, racemose, or paniculate, consisting of spikelets com- 

 posed of two-many 2-ranked imbricated bracts, the 2 lowest in the complete 

 spikelet always empty (glumes), 1 or both sometimes wanting. One or more 

 of the upper bracts (lemmas) usually contains in the axil a flower, which is 

 usually inclosed by a bract-like awnless organ called the palet, placed opposite 

 the lemma with its back to the axis (rachilla) of the spikelet, generally 

 2-keeled. Flowers perfect or staminate, sometimes monoecious or dioecious, 

 subtended by 1-3, usually 2 minute hyaline scales (lodicules) placed at the 

 base of the ovary opposite the palet. Stamens 1-6, usually 3; anthers 2-celled, 

 versatile, longitudinally dehiscent. Ovary 1-celled, 1-ovuled; styles 1-3, 

 usually 2 and lateral; stigmas hairy or plumose. Fruit a seed-like grain 

 (caryopsis). Endosperm starchy. 



Various terms have been used to designate the bracts (glumes) of the 

 spikelets. In the treatment here Mr. C. V. Piper's suggestion has been adopted, 



