802 HALORAGIDACEAE (WATER MILFOIL FAMILY) 



* * Fruit slender-pediceled. 



4. G. f ilipes Spach. Nearly smooth ; stem slender, 6-12 dm. high ; leaves 

 linear, mostly toothed, tapering at base ; branches of the panicle very slender, 

 naked ; fruit obo void-club-shaped, 4-angled at the summit. (G. Michauxii 

 Spach.) Open places, S. C. and Fla. to Tenn. and Okla. ; also said to occur 

 from Va. to O. and Kan., a range in need of further confirmation. 



6. STENOSlPHON Spach. 



Calyx prolonged beyond the ovary into a filiform tube. Fruit 1-celled, 

 1-seeded. Habit of Gaura. (From ffrei/6j, narrow, and <ri<j>uv, a tube.) 



1. S. linifblius (Nutt.) Britton. Slender, 6-12 dm. high, glabrous, leafy ; 

 leaves narrowly lanceolate to linear, pointed, entire, much reduced above ; 

 flowers numerous in an elongated spike, white, 1.2 cm. long ; fruit pubescent, 

 ovoid, 8-ribbed, 2.5-3 mm. long. (S. virgutus Spach.) Gravelly hills and dry 

 prairies, e. Kan. to Col. and Tex. 



7. TRAPA L. WATER NUT. WATEK CALTROP 



Calyx-tube short, inclosing the base of the ovary ; limb 4-parted, the seg- 

 ments persistent and becoming spinescent. Fruit indehiscent, large, with 24 

 strong spines, 1-celled, 1-seeded. Aquatic plants, with opposite or whorled 

 leaves, the upper crowded, with inflated petioles, rhombic, coarsely toothed, the 

 submersed remote, with capillary segments ; flowers borne among the floating 

 leaves. (Name abridged from calcitrapa, a caltrop, in allusion to the spreading 

 points of the fruit.) 



1. T. N.XTANS L. (WATER CHESTNUT.) Fruit 4-horned ; seed edible. Quiet 

 streams and ponds, Middlesex Co., Mass. ; Schenectady Co., N. Y. (Introd. 

 from Eurasia.) 



8. CIRCAEA [Tourn.] L. ENCHANTER'S NIGHTSHADE 



Calyx-tube slightly prolonged, the end filled by a cup-shaped disk, deciduous ; 

 lobes 2, reflexed. Fruit indehiscent, small and bur-like, bristly with hooked 

 hairs, 1-2-celled ; cells 1-seeded. Low perennials, with opposite leaves oil 

 slender petioles, and small whitish flowers in racemes, produced in summer. 

 (Named for Circe, the enchantress.) 



1. C. lutetiana L. Tall (3-9 dm. high); leaves ovate, tending to ovate- 

 oblong, mostly rounded at the base, of rather firm texture, slightly toothed ; 

 bracts none ; hairs of the roundish pyriform 2-celled fruit bristle-like (rarely 

 wanting). Common in dry open woods, N. S. to Ont., and southw. (Eu.) 



2. C. intermedia Ehrh. Lower, 2-4 dm. high ; leaves thin, ovate, the 

 middle and upper more or less cordate, the teeth salient ; minute bracts 

 usually present ; petals as long as the calyx ; fruit nearly as in the preceding. 

 Deep shade, e. Que. to Ont., la., and Tenn. (Eu.) Not always well marked. 



3. C. alpina L. Low (7-20 cm. high), smooth, weak,' leaves heart-shaped, 

 thin, shining, coarsely toothed ; bracts minute ; petals usually shorter than the 

 calyx ; hairs of the obovoid l-celled fruit soft and slender. Deep woods, Lab. 

 to Alaska, s. to Ga., Ind., Mich., n. e. la., and S. Dak. (Eu.) 



HALORAGIDACEAE (WATER MILFOIL FAMILY) 



Aquatic or marsh plants (at least in northern countries), with the incon- 

 spicuous symmetrical (perfect or unisexual) flowers sessile in the axils oj 

 leaves or bracts, calyx-tube adherent to the ovary, irhi<-h <*> insists of 2-4 more 

 or less united carpels (or in Hippuris of only one carpel), the styles or sessile 

 stigmas distinct. Limb of the calyx obsolete or very short in fertile flowers 



