182 HALORAGEiE. ( WATER-MILFOIL FAMILY.) 



2. P. pectinacea, Lam. Leaves all pectinate, the divisions linear-awl 

 shaped ; fruit rather obtusely angled. — Sandy swamps, near the coast, Mass. 

 to Fla. and La. 



3. HlPPUmS, L. Mare's Tail. 



Flowers perfect or polygamous. Calyx entire. Petals none. Stamen one, 

 inserted on the edge of the calyx. Style single, thread-sliaped, stigmatic down 

 one side, received in the groove between the lobes of the large anther. Fruit 

 nut-like, 1-celled, 1-seeded. — Perennial aquatics, with simple entire leaves in 

 whorls, and minute flowers sessile in the axils in summer. (Xame from Itttto^, 

 a horse, and ovpd, a tail.) 



1. H. vulgaris, L. Stems simple (1 -2° high) ; leaves in whorls of 8 or 

 12, linear, acute ; fruit nearly \" long. — Ponds and springs, Penn. to Ind. and 

 Minn., and northward. (Eu.) 



4. CALLITRICHE, L. Water-Starwort. 



Flowers monoecious, solitary or 2 or .3 together in the axil of the same leaf, 

 wholly naked or between a pair of meml)rauaceous bracts. Sterile flower a 

 single stamen ; filament bearing a heart-shaped 4-celled anther, which bv con- 

 fluence becomes 1-celled, and opens by a single slit. Fertile flower a single 4- 

 celled ovary, either sessile or pedicelled, bearing 2 distinct and filiform sessile. 

 usually persistent stigmas. Fruit nut-like, compressed, 4-lobed, 4-celled, sep- 

 arating at maturity into as many closed 1-seeded portions. Seed pendulous, 

 filling the cell; embryo slender, straight or slightly curved, nearly the lengtli 

 of tlie oily albumen. — Low, slender and usually tufted, glabrous, or beset 

 with minute (microscopic) stellate scales, with spatulate or linear entire leaves, 

 both forms of leaves often occurring on the same stem. (Xame from KaKos, 

 beautiful, and epl^,hair, from the often almost capillary stems.) 



* Small annuals, forming tufts on moist soil, destitute of stellate scales: leaves 

 uniform, very small , ohovate or oblanceolate,3-nerved,croicded : bracts none, 



1. C. deflexa, Braun, var. Austini, Hegelm. Stems ^- I' high; fruit 

 small (I" broad), broader than high, deeply notched above and below, on a 

 pedicel often nearly of its own length or nearly sessile ; lobes of the fruit nar 

 rowly winged and with a deep groove between them ; persistent stigmas shortei 

 than the fruit, spreading or reflexed ; leaves 1 - 2" long. (C- Austini, Engelm.) 

 — On damp soil, N. Y. and N. J. to 111., Mo., and Tex. (S. Am.) 



* * Amphibious perennials; leaves with stellate scales, tlie floating ones obovate 



and 3-nerved, the submersed linear {all uniform and narrow in terrestrial 

 forms) ; flowers usually between a pair of bracts. 



2. C. verna, L. Fruit (^" long) higher than broad, obovate, slightly ob^ 

 cordate, usually thickest at the base, sessile, its lobes sharply keeled or very 

 narrowly winged above, and with a wide groove between them ; stigmas shorter 

 than the fruit, almost erect, usually deciduous ; floating leaves crowded in a 

 tuft, obovate, narrowed into a petiole. — Common in stagnant waters. New 

 England to Fla., west to Minn., Tex., and the Pacific. (Eu.) 



3. C. heterophylla, Pursh. Fruit smaller, as broad or broader than 

 high, deeply emarginate, thick, almost ventricose, sessile or nearly so, its lobes 



