CALLITRICHACE.E. (WATER-STARWORTS.) 427 



Order 93. SAUEUBACEJ1. (Lizard's-tail Family.) 



Herbs, with jointed stems, alternate entire leaves, and perfect flowers in 

 spikes, entirely destitute of any floral envelopes, and ivith 3-5 more or less 

 separate or united ovaries. — Ovules few, orthotropous. Embryo heart- 

 shaped, minute, contained in a little sac at the apex of the albumen. — An 

 offshoot of the (tropical) Pepper Family, and represented only by 



1. SAURURUS, L. Lizard's-tail. 



Sramens mostly 6 or 7, hypogynous, with distinct filaments. Fruit somewhat 

 fleshy, wrinkled, of 3 -4 pistils united at the base. Stigmas recurved. Seeds 

 usually solitary, ascending. — Perennial marsh herbs, with heart-shaped con- 

 verging-ribbed petioled leaves, without distinct stipules ; flowers (each with a 

 small bract) crowded in a slender wand-like and naked peduncled terminal 

 spike or raceme (its appearance giving rise to the name, from <ravpos, a lizard 

 and ovpd, tail). Bract adnate to or borne on the pedicel. 



1. S. C^rnuus, L. Flowers white, in a dense spike nodding at the end; 

 bract lanceolate; filaments long and capillary. — Swamps: common. June- 

 Aug. 



Order 94. CEEATWHYLLACEJ1. (Hornwokt Family.) 



Aquatic herbs, with ivliorled finely dissected leaves, and minute axillary 

 and sessile monoecious flowers without floral envelopes, but with an 8-12- 

 cleft involucre in place of a calyx, the fertile a simple 1-celled ovary, with a 

 suspended orthotropous ovule : seed filed by a highly developed embryo with 4 

 cotyledons ! and, a conspicuous plumule. — Consists only of the genus 



1. CERATOPHYLLUI, L. IIornwort. 



Sterile flowers of 12-*24 stamens, with large sessile anthers. Fruit an ache- 

 nium, beaked with the slender persistent style. — Herbs growing under water, 

 in ponds or slow-flowing streams : the sessile leaves cut into thrice-forked thread- 

 like rigid divisions (whence the name from nepas, a horn, and (pvWov, leaf). 



1- C. demersum, L. — Var. commune has a smooth marginless fruit 

 beaked with a long persistent style, and with a short spine or tubercle at the 

 base on each side. — Var. echinatum (C. echinatum, Gray) has the fruit 

 mostly larger (3" long), rough-pimpled on the sides, the narrowly winged mar- 

 gin spiny-toothed. — Slow streams and ponds : common, but rarely seen in fruit. 

 Probably there is only one species. (Eu.) 



Order 95. CALX.ITRICHACE.aE. (Water-Starworts.) 



Small annuals or perennials, mostly aquatics, with opposite entire leaves 

 and axillary monozcious flowers without any proper floral envelopes, and with 

 a 4-lobed and ^-celled A-seeded fruit ; — consisting only of the genus Calli- 

 triche (regarded by many botanists, perhaps with good reason, as repre- 



