424 AROIDEjE. [Arum. 



Cornwall to Sussex, very local ; Channel Islands; fl. June.— A larger, stouter 

 plant than A . macula'tum, leaves more triangular ; spathe falling over 

 at the top as soon as it expands ; spadix always yellow ; pistillodes much 

 longer ; berries longer; seeds larger. — Distrib. W. France, S. Europe, N. 

 Africa. 



2. A'CORUS, L. Sweet-flag. 



Rootstock creeping. Leaves radical, ensiform, equitant. Scape flattened. 

 Spathe continuous with the scape, 2-edged. Spadix lateral, terete, nar- 

 rowed upwards, covered with flowers. Perianth-segments 6, free, mem- 

 branous, oblong, persistent. Stamens 6, on the base of the segments, 

 r) laments flattened ; anthers didymous. Ovary 2-3-celled ; stigma sessile, 

 minute ; ovules many, pendulous from the top of the cell, orthotropous. 

 Berry 6-gonous, full of mucus. Seeds 1-3, testa thin, albumen horny ; 

 embryo green, cylindric, radicle next the hilum. — Distrib. Europe, temp. 

 Asia and America ; species 2. — Etym. Classical. 



A. Calamus, L. ; midrib of leaf thick. 



Ditches, ponds, &c, from York and Lancaster to Somerset and Sussex, rare ; 

 naturalized in Scotland and Ireland ; fl. June-July. Leaves 3-6 ft., §-lJ in. 

 diarn., margins waved. Scape leaf-like, ^ in. diam. Spathe long. Spadix 

 3-4 in., | in. thick, curved. Perianth-segments not longer than the ovary. 

 Fruit obovoid, top pyramidal.— Distrib. Europe (excl. Greece), N. Asia, 

 Himalaya, N. America. — Aromatic, stimulant, tonic. Supposed to have 

 been introd. from India. I have never seen fruit. 



Order LXXXV. LEMNA'CEJE. 



Minute annual floating green scale-like plants, rootless or with capil- 

 lary simple roots, propagated by budding, and by autumnal hibernating 

 bulbils, rarely by seed ; vascular tissue or rudimentary ; roots tipped by 

 a membranous sheath. Flowers rarely produced, most minute, 1-3 in a 

 spathe, or naked. Perianth 0. Stamens 1-2 ; anthers 1-2-celled, de- 

 hiscence transverse ; pollen spherical. Ovary 1 -celled ; style short, 

 stigma truncate or funnel-shaped ; ovules 1-7, orthotropous anatropous 

 or ^-anatropous. Utricle bottle-shaped. Seeds 1 or more, testa coriaceous, 

 inner coat thickened and discoid over the radicle, albumen fleshy or ; 

 embryo axile, straight, stout, cylindric. — Distrib. All standing waters ; 

 genera 2 ; species about 20. — Affinities. With Naiadacece and Aroidcoe. 

 — Properties 0. 



Frond with 1 or more capillary roots. Anthers 2-celled 1. Lemna. 



Frond rootless. Anthers 1-celled 2. Wolffia. 



