Parr 1, 1909] ELODEACEAE 69 
spathe ovoid, 8-10 cm. long; peduncles of the pistillate plant thread-like, 3-6 dm. long, in 
fruit spirally twisting, drawing the fruit under water; spathe tubular, usually close around 
the flower, 1-1.5 cm. long; |hypanthium in flower 1-2 cm. long, 1.5-2 mm. thick, in fruit 
5-12 cm. long; sepals elliptic, 2-3 mm. long; petals minute; stigmas sessile, ovate in 
outline, 2-cleft for less than half their lerigth. 
TYPE LOCALITY: Pisa [Italy]. 
DISTRIBUTION : In water from Nova Scotia to Virginia, Indiana, and South Dakota; also in 
Europe and Asia. 
ILLUSTRATIONS: Lam. Encyc. £1. 799; Dict. Sci. Nat. p/. 78, 79, Spach, Hist. Vég. p/. 171; FI. 
tae ed. 5, pl. 386; T. Nees, Gen. 62. 431; Britt. & Brown, Ill. Fl. £208; E. & P, Nat. PA. 2: /. 
2. Vallisneria americana Michx. Fl. Bor. Am. 2: 220. 1803. 
Leaves thicker than in the preceding, linear, 3-6 dm. long, 6-20 mm. wide, obtuse, 
often minutely denticulate on the margin ; peduncles of the pistillate plant 5-10 dm. long, 
curved, but scarcely spirally twisted in fruit; spathe 2-2.5 cm. long, rather loose; hypan- 
thium in flowers 2.5-3 cm. long, fully 2 mm. thick, in fruit about 1 dm. long; sepals 
oval, 5-6 mm. long, rounded at the apex; petals about 2 mm. long; stigmas large, about 
5 mm. long, 2-cleft to near the base; each division obliquely obovate, abruptly short- 
acuminate. 
TYPE LOCALITY: Mississippi River. _ 
DISTRIBUTION : Florida to Mississippi. 
3. PHILOTRIA Raf. Am. Monthly Mag. 2: 175. 1818. 
Elodea Michx. Fl. Bor. Am.1: 20. 1803. Not Zlodes Adans. 1763. 
Udora Nutt. Gen, 2: 242. 1818. 
Anacharis Bab. & Planch. Ann. Mag. Nat. Hist. II.1: 81, mainly. 1848. Not Axacharis Rich. 
1811 
Apalanihe Planch, Ann. & Mag. Nat. Hist. II. 1: 87. 1848. 
Submerged water-plants with elongate branched stems, often rooting at the nodes. 
Leaves opposite or whorled, sessile, pellucid, 1-nerved and usually minutely denticulate. 
Plants usually dioecious or polygamo-dioecious, rarely with only perfect flowers. Spathes 
2-cleft at the apex ; that of the staminate plant in our species ovoid or obovoid, sessile or 
peduncled; in the pistillate or hermaphrodite plant lanceolate or lance-tubular. Staminate 
flowers ‘solitary, rarely in threes, sessile or nearly so, early separating from the plant and 
floating on the surface of the water; sepals and petals 3; stamens 9, in two series, the 
outer of 6 and the inner of 3 stamens. Pistillate flowers solitary, sessile; hypanthium 
prolonged in a long, slender tube; sepals and petals 3; stamens none or represented by 3 
rudimentary filaments. Hermaphrodite flowers like the pistillate ones, but with 3-9 sta- 
mens. Fruit linear or lance-linear. Seeds 3-21. 
Type species, Zlodea canadensis Michx. 
Leaves oblong or ovate-oblong, mostly obtuse ; staminate flowersunknown. 1. P. canadensis. 
Leaves linear or oblong, acute; hermaphrodite flowers unknown. 
Staminate spathe sessile. 
Leaves oblong or linear-oblong, 2-3 mm. wide; spathe of the stami- 
nate flowers 5-6 mm. long; anthers 2-2.5 mm. long. 2. P. Nuttallit. 
Leaves linear, 1.5 mm. wide or less (rarely 2 mm. wide); staminate 
spathe 2-3 mm. long; anthers about 1 mm. long. 
Leaves 1-2 cm. long; sepals and petals 1.5-2 mm. long. 3. P. angustifolia. 
Leaves 5-8 mm. long ; sepals and petals 1-1.5 mm. long. 4. P. minor. 
Staminate spathe peduncled. . 
Staminate spathe ovoid, abruptly contracted at the base ; sepals 2.5 mm. 
long ; petals present. 5. P. linearis. 
Staminate spathe obovoid, tapering at the base; sepals of the staminate 
flowers 5mm. long; petals wanting. 6. P. Planchonit, 
1. Philotria canadensis (Michx.) Britton, Science II. 2: 5. 1895. 
Elodea canadensis Michx. Fl. Bor. Am. 1: 20. 1803. 
Anacharis Alsinastrum Bab. Ann, Mag. Nat. Hist. II. 1: 83. 1848. 
? Anacharis canadensis Planch. Ann. Mag, Nat. Hist. II. 1: 86. 1848. 
Elodea latifolia Casp. Jahrb. Wiss. Bot. 1: 467. 1858. 
Stem slender, 3-10 dm. long, usually with short internodes ; leaves verticillate in 3’s 
or 4’s, or the lower ones in 2’s, sessile; blades oblong or ovate-oblong, usually obtuse, 5-10 
