398 CALLITRICHACE^E. ( WATER-STARWORT FAMILY.) 



1. SAUKUBUS, L LIZARD'S-TAIL. 



Stamens 4-8, with long club-shaped filaments. Fruit somewhat fleshy, com- 

 posed of 3 - 4 partly united 1 - 2-seeded carpels, pointed with as many stigmas. 

 Flowers white. 



1. S. cermiUS, L. Stem erect, branching; leaves petioled, cordate-ovate, 

 or oblong-ovate, acuminate ; spikes white, terminal, nodding at the apex ; flow- 

 ers numerous, each from the axil of a small bract. Marshes and muddy banks, 

 Florida, and northward. May -Aug. > Rhizoma creeping. Stem 1- 2 high. 

 Spikes 4' -6' long. 



ORDER 116. CERATOPHYL-LACE^E. (HORNWORT 

 FAMILY.) 



Submerged aquatic herbs, with filiform jointed and branching stems, 

 finely dissected whorled leaves, and small axillary monoecious flowers, 

 destitute of floral envelopes, but surrounded by an involucre of 8-12 

 linear leaves. Anthers 12-24, oblong, 2-3-toothed, sessile. Ovary 

 solitary, simple, with a single suspended orthotropous ovule. Achenium 

 compressed, pointed with the slender persistent style. Albumen none. 

 Cotyledons 4. Plumule conspicuous. Consisting of the single genus 



1. CERATOPHYLLUM, L. HORNWORT. 



1. C. demersum, L. Leaves rigid, 6 - 9 in a whorl, once or twice forking, 

 with the lobes spiny-toothed ; achenium oval, compressed, tubercular-roughened 

 on the sides, and armed near the base with 2 lateral widely-spreading slender 

 spines. In still water, Florida, and northward. Sept. and Oct. Stems 1- 

 4 long. Leaves near the end of the branches much crowded. 



2. C. echinatum, Gray ? Leaves weak, 9-12 in a whorl, 3-4 times 

 forking, the ultimate segments bristly -toothed ; ovaries warty, unarmed ; ache- 

 nium oblong, tubercular-roughened on the sides, the edges margined and armed 

 with 5-7 strong and spreading spines. Shallow ponds, on St. Vincent's Isl- 

 and, West Florida. May. Stems 6' - 12' long. 



3. C. SUbmersum, L. Leaves hair-like, 3-4 times forking, bristly- 

 toothed ; achenium oblong, slightly compressed, tubercular-roughened, with' 

 rounded margins, unarmed. South Florida, Dr. Blodgett. Stems 6' - 12' 

 long. 



ORDER 117. CALLJTRICHACEJE. (WATER-STARWORT 



FAMILY.) 



Small aquatic annuals, with opposite entire leaves, and solitary axillary 

 polygamous flowers without floral envelopes. Stamen mostly solitary, 2- 

 bracted in the sterile flower. Filament slender : anther reniform, the 



