212 HALORAGIDACEAE 



1. Circaea alpina L. Small Enchanter's Nightshade. Fig. 3456. 



Circaea alpina L. Sp. PI. 9. 1753. 



Erect, simple or branching, glabrous or puberulent above, 1-3 dm. tall. Leaf-blades cordate, 

 1.5-5 cm. long, almost or quite as wide, acute or acuminate, coarsely dentate, on petioles 1.5- 

 3.5 cm. long; pedicels Z-A mm. long, reflexed in fruit; sepals and petals about 1 mm. long; 

 capsule narrowly obovoid, 1-celled, 2 mm. long, covered with weak soft hooked hairs. 



Cold and moist woods, Boreal Zones; Alaska to Washington east to the Atlantic Coast; also Eurasia. Type 

 locality: Europe. July-Aug. 



2. Circaea pacifica Aschers. & Magnus. Pacific Enchanter's Nightshade. 



Fig. 3457. 



Circaea pacifica Aschers. & Magnus, Bot. Zeit. 29: 392. 1871. 



Circaea alpina f. pacifica G. N. Jones, Univ. Wash. Pub. Biol. 5: 195. 1936. 



Stem from a short rootstock, simple, 2-4 dm. tall; plant glabrous. Leaf-blades ovate, 

 sometimes orbicular, usually rounded at the base, sometimes cordate, entire or minutely denticu- 

 late or obscurely repand-denticulate, 2-6 cm. long, acuminate; petioles 2-3 cm. long; racemes 

 bractless; sepals and petals about 1 mm. long; capsule narrowly obovoid, 1-celled, 1.5-2 mm. 

 long, with hooked hairs. 



Deep woods, Transition Zone; British Columbia to San Bernardino County, California, and the Rocky Moun- 

 tains. Type locality: near San Francisco, California. June-Aug. 



Family 107. HALORAGIDACEAE. 

 Water-milfoil Family. 



Perennial, mainly aquatic herbs, with alternate or verticillate leaves, the sub- 

 merged ones often pectinate-pinnatifid, or pinnately divided into fine capillary divi- 

 sions. Flowers perfect or unisexual, axillary, solitary or clustered, or in interrupted 

 spikes. Calyx of 2-A sepals, or reduced to a narrow ring on the rim of the adnate 

 hypanthium. Petals when present 2-4, small. Stamens 1-8. Ovary inferior, 1-4- 

 celled ; styles 1-4. Fruit a nutlet or drupe-like, angular, ribbed or winged, with 2-4 

 1-seeded carpels. Endosperm fleshy ; cotyledons minute. 



A family of 7 genera and about 100 species, of wide geographical distribution. 



Submerged leaves pinnatifid, the cmersed ones entire or toothed; petals 4 in staminate flowers; stamens 4-8; ovary 



2-4-celled. 1- Myrtophyllum. 



Leaves all simple and entire; petals none; stamen 1; ovary 1-celled. 2. Hippuris. 



1. MYRIOPHYLLUM [Vaill.] L. Sp. PI. 992. 1753. 



Aquatic or terrestrial herbs, with verticillate or alternate leaves, the emersed ones 

 entire, dentate, or pectinate, the submerged ones pinnatifid into capillary segments. Flowers 

 usually monoecious, 2-bracted, in the upper axils, often forming an interrupted spike, the 

 upper ones generally staminate, the lower pistillate, and the intermediate often perfect. 

 Staminate flowers with a very short hypanthium, 2-4 sepals, 2-4 petals and 4-8 stamens. 

 Hypanthium of pistillate flowers 4-grooved. Sepals 4, minute, or sometimes reduced to a 

 mere ring. Ovary 2-4-celled ; ovules 1 in each cell, pendulous ; style 4, short, often plumose. 

 Fruit splitting when ripe into 4 indehiscent 1-seeded bony carpels. [Name from the 

 Greek myrios, numberless, and phyllon, leaf.] 



About 20 species, of wide geographical distribution. Type species M yriophyllutn spicatum L. 

 Petals fugacious; stamens 8; flower-verticils in a terminal emersed interrupted spike; floral leaves reduced to 

 bracts, shorter or but slightly exceeding the fruits. 



Bracts entire or the lower serrate, spatulate-obovate. 1. M. exalbescens. 



Bracts pectinate. 2. M. verticillatum. 



Petals tardily deciduous; stamens 4; flower-verticils in the axils of the linear pectinate emersed leaves, these 

 much exceeding the flowers. 3. M. htppurtoides. 



1. Myriophyllum exalbescens Fernald. American Milfoil. Fig. 3458. 



Myriophyllum exalbescens Fernald, Rhodora 21: 120. 1919. 



Myriophyllum spicatum var. exalbescens Jepson, Man. Fl. PI. Calif. 691. 1925. 



Stems simple or branching, 3-9 dm. high, submerged leaves in whorls of 3 or 4, commonly 

 12-30 mm. long, pinnately divided into 7-11 pairs of capillary segments, the rachis scarcely 

 thicker than the capillary segments ; flowers in emersed almost naked spicate verticils ; floral 

 bracts rarely equaling the fruit, spatulate-obovate or cochleiform, the lower serrate, the upper 

 entire ; petals fugacious, oblong-obovate, concave, 2 . 5 mm. long ; stamens 8, about 1 . 5 mm. long ; 

 fruit subglobose, 2.5-3 mm. long; carpels rounded on the back, smooth or rugulose. 



Ponds and quiet streams, mainly Transition and Upper Sonoran Zones; throughout the Pacific States and east 

 across the continent, closely related to the Old World M. spicatum L. Type locality: York River, Quebec. July- 

 Sept. 



