396 LEMNACE^E. [LEMSA. 



rare and local (if native) in Scotland; Mid. Ireland, rare. Frond ^-J in., 

 dark green above, purple beneath, tracheae abundant ; epidermal cells with 

 flexuous walls. Spathe 2-lipped. Stamens 2.--DISTRIB. Europe, Siberia. 

 Madeira, N. America. Flower unknown in Britain. 



2. WOLFF'IA, Horlcel. 



Fronds like grains of sand, rootless, oblong or subglobose, flattened above, 

 proliferous, cleft near the base. Flowers bursting through the upper sur- 

 face of the fronds. Spathe 0. Anther sessile, 1-celled ; pollen smooth. 

 Ovary globose ; style short, stigma depressed ; ovule 1, erect, orthotropous. 

 Utricle spherical, indehiscent. Seed oblique ; albumen fleshy, scanty. 

 DISTRIB. Europe local, W. trop. Africa. ETYM. J. F. Wolff, a writer on 

 Lemna. 



1 . W. arrhi'za, Wimm. ; frond loosely cellular beneath. 

 Ponds, Essex, Middlesex, Hants, Surrey, probably common elsewhere. The 



smallest known flowering plant. Frond -' in. long, & in. broad, young 



solitary at the base of the old, soon detached ; epidermal cells with straight 



walls. Flowers described from African specimens. 



ORDER XII. TYPHA'CEJE. 



Marsh or aquatic herbs. Jtootslock creeping. Leaves narrow, linear, 

 obtuse, bases sheathing. Spathe 0. Flowers monoecious, in cylindric 

 spikes or heads, the males uppermost. Perianth or of membranous 

 scales or hairs, imbricate, persistent. MALE. Stamens few or many, fila- 

 ments slender ; anthers basifixed, oblong, 2-celled, dehiscence lateral. 

 FEMALE. Ovary sessile or stalked, 1- rarely 2-celled, contracted into a simple 

 persistent style, stigmas unilateral decurrent papillose ; ovule 1, pendulous 

 from the top of the cell. Fruit small, coriaceous, or a drape, 

 pendulous, albumen fleshy or mealy ; embryo straight, terete, radicle next 

 the hilum. DISTRIB. Temp, and trop.; genera 2; species about 12. 

 AFFINITIES. With Aroi<hxe and Pando.nece (screw-pines), of which Spar- 

 ganium is almost a member. PROPERTIES. The roots of Ty'pha are fari- 

 naceous ; and the pollen is made into cakes in Sind and New Zealand. 



Flowers in globose heads 1. Sparganiuni. 



Flowers in cylindric spikes 2. Typha. 



1. SPARGANIUM, L. BUR-REED. 



Heads globose, subtended by leafy bracts. Perianth of 3-6 spathulnte 

 membranous scales. Stamens 2-3, connective hardly produced at the tip. 

 Ovary 1- rarely 2-celled. Drupe angled, small, 1-2-celled. DISTKIK. 

 Temp, and trop. ; species about 10. ETYM. airipyavov, a band, from the 

 form of the leaf. 



1. S. ramo sum, Hudson ; erect, branched, leaves erect 3-quetrous at 

 the base keeled, stigma linear, drupes sessile broadly ovoid, beak short. 

 Ponds, ditches, and river-banks ; fl. June-July. Stem 1-4 ft. Leaves 2-5 ft., 



1 in. broad. Male faads olive-brown, deciduous, 4-j{ in. diam. ; female as 



large, 1 in. when in fruit ; bracts linear. Drupe in. DISTRIB. Europe, 



Siberia, N. Africa, N. America. 



