CALLITRICHACEAE (WATER STARWOBT FAMILY^ 549 



with nearly naked lobes and small almost sessile glands; styles shorter than 

 the ovary, spreading or recurved; pod warty; seeds delicately reticulated 

 {E. arkansana and var. missouriensis Norton.) — Prairies and roadsides, Mo 

 to Ala., and westvv. May-July. 



24. E. Hei,iosc6pia L. (Waetweed.) Stems ascending, 1.5-3.5 dm. high, 

 stout ; leaves all obovate and very rounded or retuse at the end, finely serrale, 

 smooth or a little.hairy, those of the stem wedge-shaped ; umbel divided into fj 

 rays, then into 3, or at length simply forked ; glands orbicvlar, stalked; pads 

 smooth and even I seeds with coarse honeycomb-like reticulations. — Waste places., 

 and dry open soil, e. Que, to Ont., abundant ; locally s. to Pa., 0., and 111. (Na,(, 

 from Eu. ) 



+- H- Leaves entire ; glands crescent-shaped or 2-horned. 

 ** Seeds smooth and dark-colored; perennials, with running rootstocks. 



25. E. ^suLA L. Stems clustered, 3-4 dm. high ; leaves lanceolate to linear, 

 the floral (yellowish) broadly heart-shaped, muoronate ; umbel divided into many 

 rays, then forking ; glands short-horned (brown) ; pods smoothish and granular. 



— Sandy banks, s. Me. (Parliyi) to N. J., Pa., and Mich. (Nat. from Eu.) 



26. E. CvPARfssiAS L. (Cypress S.) Stems densely clustered, 1.2-3 dm. 

 high; stem-leaves. linear, crowded, the floral heart-shaped; umbel many-rayed ; 

 glands crescent-shaped; pods granular. — Escaped from gardens, common. 

 (Introd. from Eu.) 



27. E. LtJOiDA Waldst. & Kit. Stout and tall glabrous perennial ; leaves 

 oblong or oblong-lanceolate, the floral broadly heart-shaped, mucronate ; termi- 

 nal umbel many-rayed, the rays forking ; glands short-horned ; pods finely 

 wrinkled. {E. nicaeensis Man. ed. 6, not All.) — Field and roadsides, Sus- 

 quehanna Valley, N. Y. and Pa. (Nat. from Eu.) 



++ ++ Seeds sculptured, ash-colored ; pod smooth ; annuals or biennials. 



28. E. PtpLus L. (Petit S.) Erect or ascending, 1 .5-3 dm. high ; leaves 

 round-obovate, the upper floral ones ovate ; umbel 3-rayed, then forking ; glands 

 long-horned ; lobes of the pod 2-wing-crested on the back ; seeds ^.-grooved on 

 the inner face, pitted on the hack, scarcely over 1 mm. long. — Waste places 

 and cultivated ground, N. B. to N. J., Pa., and la. (Adv. from Eu.) 



29. E. commutata Engelm. Stems branched from a commonly decumbent 

 base, 1.5-3 dm. high; leaves obovate, obtuse, the upper all sessile, the upper 

 floral ones roundish-dilated, broader than long ; umbel 3-forked ; glands with 

 slender horns ; capsule obtusely angled; seeds ovoid, pitted all over, 2 mm. long. 



— Along streams and shady slopes. Pa. to Fla. , Mo., and Minn. 



* * * Glabrous annual or biennial with entire opposite and decussate leaves, an 

 umbelliform inflorescence, and short-horned glands. 



30. E. LAthyeus L. (Caper S., Mole Plant.) Stem stout, 8-9 dm. high ; 

 leaves thick, linear or oblong, the floral oblong-ovate and heart-shaped ; umbel 

 4-rayed, then forking. — Sparingly escaped from gardens, Ct. and N. Y. to N. C. 

 (Introd. from Eu.) 



CALLITRICHACEAE (Water Starwort Family) 



Low slender and usually tufted chiefly aqjuatic herbs (glabrous or beset with 

 m,icroscopic stellate scales), with entire spatulate or linear leaves, monoecious 

 flowers (solitary or 2 or 3 together in the axil of the same leaf) wholly naked or 

 inclosed by a pair of membranaceous brads. Sterile flower a single stamen, 

 the filament bearing a heart-shaped 4-celled anther, which by confluence becomes 

 1-celled, and opens by a single slit. Fertile flower a single 4-celled ovary, bear- 

 ing 2 distinct filiform stigmas. Fruit nut-like, compressed, 4-lobed, 4-celled, 

 separating at maturity into as many closed 1-seeded portions. Seeds pendulous * 

 embryo slender, straight or slightly curved, nearly the length of the oily albumeu 



