544 
CVII. ARACEA5 
*Acorus Calamus, Linn. ; FI. Br. Ind. vi. 555. An aromatic, 
erect herb ; rootstock thick, creeping ; stems 6-12 in., flat. Leaves 
radical, tufted, 2-3 ft. by about J in. broad, resembling those of 
an Iris, margins crimped. Spathe leaf -like, long, narrow, not 
enclosing the spadix. Spadix 1J-3 in., tapering, not prolonged, 
destitute of neutral organs, covered with small, yellow-green, 
2-sexual flowers. Perianth-segments 6, free, persistent. Stamens 
6, at the base of the segments. Ovary free., oblong, 3-celled, top 
conical ; ovules many. Berries yellow-green, angular from mutual 
compression, 1-3-seeded. 
Throughout India, in marshes or on river banks, ascending to 8000 ft. ; 
June, July. — Temperate and warm regions of the North Hemisphere. (Britain, 
Sweet Flag.) 
CVIII. LEMNACE^E 
Minute, floating plants growing in colonies, consisting of leaf-like 
fronds, either separate or cohering two or three together by their 
edges and usually emitting one or several root-fibres from their 
lower surface. Flowers 1 -sexual, male and female on the same 
plant, issuing from a fissure in the edge or on the upper surface 
of the frond, usually at first enclosed in a minute, membranous 
bract or spathe. Perianth none. Stamens 1 or 2. Ovary 1-celled ; 
style short ; ovules 1-7. Fruit a bottle-shaped utricle containing 
one or more seeds. — In stagnant water over nearly the whole 
world. 
The propagation of these plants is effected usually by means of new fronds 
growing out of the margins of the old ones or by bulbils. Flowers are rarely 
produced. 
Fronds with roots. Flowers in marginal clefts . . . .1. Lemna. 
Fronds exceedingly small, without roots. Flowers bursting through 
the upper surface ........ 2. Wolffici, 
1. LEMNA. The classical name. — Nearly all temperate and 
tropical regions. 
Fronds bearing root-fibres. Flowers in marginal clefts of the 
fronds, at first enclosed in a minute spathe. Stamens 1-2, fila- ' 
ments slender ; anthers 2-celled. Ovules 1-7. 
Root-fibre single. 
Fronds J in. ; lower surface nearly flat . . . 1 . L. minor. 
Fronds in. ; lower surface much swollen . . . 2. L. gibba. 
Root-fibres several . . . . . . . . 3. L. polyrhiza. 
1. Lemna minor, Linn. ; FI. Br. Ind. vi. 556. Boot-fibre 
single. Fronds J— J in. long, broadly ovate or oblong, both sur- 
faces nearly flat. Stamens 2. Ovule 1. 
