Hippuris.] HALORAG-E&. 151 



Order XXX. HALORA'GEffl. 



Herbs or shrubs, often marsh or aquatic, with much-reduced or imper- 

 fect perianths. Leaves opposite alternate or whorled, exstipulate. Flowers 

 often minute and 1 -sexual. Calyx superior ; lobes 2, 4, or 0, valvate or 

 slightly imbricate in bud. Stamens 1-8, epigynous in the 2-sexual flowers, 

 filaments usually short ; anthers (except in Callitriche) long, 4-angled, 

 basifixed, slits lateral. Disk small or 0. Ovary inferior, mostly of 2 or 

 4 connate (rarely of 1) carpels ; styles or stigmas as many as the carpels, 

 2 in Callitriche ; ovules 1 in each cell, pendulous, anatropous. Fruit 

 2-4-celled, indehiscent, or of 1-4 small 1-seeded drupes. Seed pendulous, 

 testa membranous, albumen fleshy ; embryo cylindric, axile, or minute. 

 Distrib. Widely dispersed ; genera 9 ; species 80. — Affinities. Obscure, 

 probably near Saxifragece and Rhizophorece. — Properties unimportant. 



Leaves all whorled, entire. Petals 1. Hippuris. 



Leaves all or lower whorled, much cut. Petals 2-4 2. Myriophyllum. 



Leaves all opposite, quite entire. Perianth 3. Callitriche. 



I. HIPPU'RIS, L. Mare's-tail. 



Glabrous, aquatic herbs. Stems stout, erect, simple, leafy. Leaves 

 whorled, narrow, quite entire. Flowers minute, solitary, sessile, axillary, 

 sometimes 1 -sexual. Calyx-tube subglobose, limb entire. Petals 0. 

 Stamen 1. Ovary 1-celled ; style subulate, stigmatose throughout its 

 length. Drupe ovoid, stone crustaceous. Seed oblong, albumen scanty. 

 — Distrib. Arctic and temp. N, hemisphere, Chili, Fuegia ; species 1 or 

 2. — Etym. 'iirnos and ovpd, horsetail. 



H. vulgaris, L. ; leaves 6-10 in a whorl linear acute. 



Margins of lakes, ponds, &c, from Shetland to Kent and Cornwall, local ; fl. 

 June-July. — Rootstock submerged, stout, creeping. Stem 6-24 in., terete, 

 very many-jointed, as thick as a goose-quill or less ; rarely floating flaccid 

 and flowerless. Leaves |-1§ in., close-set, tips withered. Flowers green, 

 sessile. Anthers red. Drupe minute, smooth, green. — Distrib. Of the 

 genus. 



2. MYRIOPHYL'LUM, L. WATER MlLFOIL. 



Glabrous marsh or aquatic herbs ; branches often floating. Leaves 

 opposite alternate or whorled. Flowers small, axillary, solitary or spiked, 

 anemophilous ; upper male, lower female, intermediate often 2-sexual. — 

 Male fl. Calyx 4- rarely 2-lobed or 0. Petals 2 or 4, concave. Stamens 

 2, 4, or 8. — Fem. fl. Calyx-tube 4-grooved ; lobes 4. minute or 0. Petals 

 minute or 0. Ovary 4- rarely 2-celled ; styles 4, very short, plumose. 

 Drupe deeply 2-4-lobed. Seeds oblong; albumen copious. — Distrib. 

 Ubiquitous ; species 15. — Etym. fxvpios and <pv\Kov, from the finely-divided 

 leaves. 



