SAUItURACE^E, CERATOPIIYLLACE^ AND CALLITRlCHACE^. 313 



Order 97. SAURURACEffi.— LizarcVs-tail Family. 



Herbs, with jointed stems, alternate entire leaves ivith stipules, and perfect Jlotccrt 

 in spikes, entirely destitute of a perianth, and 3 to 5 more or less united ovaries.— 

 Ovules few, orthotropous. Fruit a capsule or berry, 3 to 5-celled, few-seeded 



SAURUBUS, Linn. Lizard's-tail, 



Gr. saura, a lizard, and oura, a tail ; in allusion to the form of the Inflorescence. 



Inflorescence an anient or spike of 1-flowered scales. 

 Stamens mostly G or 7, hjpogynous, with long and distinct 

 filaments. Fruit scnic-what fleshy, wrinkled,- of 3 or 4 

 pistils united at the base, with recurved stigmas. Seeds 

 usually solitary, ascending. — A perennial aquatic herb, with 

 heart-shaped petiolcd leaves, and white flowers, each from the axil.of 

 a small bract, closely aggregated in a slender terminal spike, 



S. cernuus, L. Lizard's-tail. 



Stem angular; leaves cordate, acuminate. 



Marrins of ponds and stream?; common. Juno— Aug. Stem 1 to 2^ feet high, 

 weak, furrowed. Leaves 4 to G inches long, l / 2 as wide, smooth and glauceous. on 

 i etioles 1 to 2 inches long. Spike slender, 3 to 6 inches long, drooping at the end 



Order 98. CERATOPHYLLACEJE.— Hornwort Family. 



Aquatic herbs, tcilit tohorled Jinety dissected leaves, and minute axillary and stStiU 

 vicnacioi'.s founs viV.oui cry feral envelope?, lh.t vrifh aviany cleft involucre. — 

 Stahens 16 to 2-1. Fertile ovart free, l-cclled with a suspended o\ule; style £Ii 

 form, oblique, sessile. Fr.ui an acheniura beaked with the indurated stigma 

 Seed containing 4 cotyledons. 



CERATOPIIYLLUM, Linn. Hornwort. 



Gr. leras, a horn, phutton, a leaf, alluding to tho horn-like divisions of the loavet. 



Sterile flowers of 12 to 24 stamens with large sessile 

 "anthers. Fruit an achenium, beaked with the slender per- 

 sistent style. — Herbs, growing under water, in ponds or sloto 

 flowing streams ,• the sesliU leaves cut into 2 or 3 forking filiform 

 rather rigid divisions. 



C. eciiixatum, A. Gray. Hornwort. 



Ac-ienium elliptical, rough-pointed on the Bides, with a Wrtn'.rial and 2 short 

 lateral spines, the slightly winged margins armed with blunt teeth, which finally 

 elongate and equal the lateral spines; divisions of the kavas minutely serrulate, 

 mostly 2-toothed at the apex. 

 Common. June, July. Flo-xcrs minute. 



Order 99. CALLITRI0HACE13.— Starwort Family. 



Aquatic :ma!l annuals, witJi opposite entire leaves., and polygamous solitary fowtrs 



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