EVENING-PRIMROSE FAMILY 605 



4-6 mm. long; capsule 5-7 mm. long, canescent. G. marginata Lehm. Plains 

 and prairies: S.D. — Tex. — Ariz. — Mont.; Mex. Plain — Submont. Ap-Jl. 



5. G. parvifolia Torr. Stem 3-4 dm. high, with erect branches, sparingly 

 strigose or in age glabrate; leaves 1-2.5 cm. long; tube of hypanthium 5 mm. 

 long; petals 4-5 mm. long, scarlet; capsule 6-7 mm. long. Dry hills and plains: 

 Tex. — Colo. — N.M. Son. — Submont. Jl-Au. 



6. G. glabra Lehm. Stem 2^ dm. high, in age straw-colored and shreddy; 

 leaves oblong or lanceolate, or those of the branches linear-lanceolate; tube of 

 hypanthium 6-7 mm. long; petals pink or brick-red, rarely white; fruit 5-6 mm. 

 long. Dry plains and prairies: S.D. — Colo. — Ariz. — Mont. Plain — Submont. 

 Je-Au. 



22. CIRCAEA L. Enchanter's Nightshade. 



Low perennial herbs, with succulent but slender stems. Leaves opposite, 

 petioled. Flowers small, in racemes. Hypanthium slightly produced beyond 

 the ovary into a slender short tube. Sepals 2. Petals 2, notched, white. Sta- 

 mens 2, alternate with the petals. Fruit 1-2-ceLled, 1-2-seeded, obovoid, inde- 

 hiscent, usually covered with hooked hairs. 



Plant 1-2 dm. high; leaves sharply dentate, usually cordate at the base. 1. C. alpina. 



Plant 3-6 dm. liigh; leaf-blades sinuately denticulate, usually truncate or rounded at 

 the base. 2. C. pacifica. 



1. C. alpina L. Stem 0.5-2 dm. high, glabrous or pubescent above; leaf- 

 blades cordate, 2.5-5 cm. long; pedicels 3-4 mm. long, reflexed in fruit; fruit nar- 

 rowly obovoid, about 2 mm. long. Cold woods: Lab. — Ga. — S.D. — Colo. — 

 Alaska; Eurasia. Mont. Jl-S. 



2. C. pacifica Asch. & Magn. Stem mostly glabrous, 1.5-3 dm. high; leaf- 

 blades ovate, 3-6 cm. long; fruit obovoid, fully 2 mm. long, spraingly pubescent. 

 Woods: Mont.— Colo.— Calif.— B.C. Jl-Au. 



Family 92. HALORAGIDACEAE. Water Milfoil Family. 



Perennial or rarely annual, caulescent herbs, aquatic or amphibious, with 

 alternate, opposite, or whorled leaves, the submerged ones often finely 

 divided. Flowers perfect or monoecious, solitary or clustered, either axil- 

 lary or in terminal spikes. Sepals 2-4. Petals usually wanting or small, 

 2-4. Stamens 1-8. Gynoecium of 1-4, somewhat united carpels. Ovary 

 1-4-celled, inferior, angled or winged; style wanting. Fruit a nutlet or drupe. 



Flowers monoecious or polygamous, 4-merovis; stamens 4 or 8; submerged leaves finely 

 pinnatifid. 1. AIyriophylujm. 



Flowers perfect, without sepals and petals; stamen 1 ; leaves all entire.* 2. HiPPtlRis. 



1. MYRIOPHYLLUM (VaUl.) L. Water Milfoil. 



Aquatic herbs, with slender stems, usually floating. Leaves alternate or 

 whorled, the emersed ones entire or pectinately lobed, the submerged ones finely 

 pectinately dissected into filiform divisions. Flowers monoecious or polyga- 

 mous, axillary or in terminal spikes, the upper ones usually staminate, with 

 short hypanthium, 2—4 sepals, 2-4 small petals and 4-8 stamens ; the intermediate 

 ones often perfect; the lower ones pistillate, with 4 minute sepals, 4 small petals, 

 or none, and a 2-4-celled ovary; stigmas 2-4, plumose. Fruit bony, splitting 

 into 2 or 4, angled nutlets. Seeds solitary in each nutlet. 



Floral leaves ovate, entire or dentate, usually shorter than the flowers. 



1. M. spicatum. 

 Floral leaves pinnatifid, much longer than the flowers. 2. A/, verticillatum. 



1. M. spicatum L. Stem submerged, 3-20 dm. long; leaves verticillate in 

 4's or 5's, 1-3 cm. long, pinnatifid into fihform divisions; flowers verticillate in 

 an interrupted spike; stigmas rounded, sessile, not elongate; sepals of the stam- 

 inate flowers usually deep purple. Still water and slow streams: Newf. — Conn. 

 — Kans. — N.M.- — Cahf. — Alaska; Eurasia. Plain — Submont. Je-Au. 



