508 LEMNACE^E 



the leaves have risen above the ground. The appendix is a rich 

 crimson, dull purple, or light pink, which is easily rubbed off, or 

 yellow. At the base of the spadix are numerous sessile ovaries 

 or carpellate flowers ; above them a row with aborted styles ; yet 

 higher up several whorls of purple sessile anthers or staminate 

 flowers ; and above them some aborted ones or staminodes. The 

 spathe and appendix soon wither, leaving the ovaries, which 

 finally become a mass of scarlet berries, conspicuous in autumn. 

 — Hedges and woods; common. --F1. April, May. Perennial. 

 The berries are poisonous. 



2. A. itdlicum, a larger species, with larger, longer-stalked, 

 hastate, winter leaves, sometimes with yellowish veins 5 spathe 

 three times as long as the spadix, nodding ; appendix yellow. — 

 Along the south coast ; local. — Fl. June. Perennial. 



2. Acorus (Sweet Sedge). — Rhizome long ; leaves radical, 

 sword-shaped ; spathe leaf-like, not convolute or contracted ; 

 spadix lateral, without an appendix ; flowers perfect ; perianth of 

 6 membranous segments ; stamens 6 ; ovary 3-chambered, superior. 

 (Name in Greek denoting that the plant has the power of curing 

 diseases of the pupil of the eye.) 



1. A. Calamus (Sweet Sedge). — The only British species, an 

 aquatic plant, with somewhat the habit of a Sedge, easily dis- 

 tinguished from all other British plants by the wavy margins of 

 the leaves, the peculiar spadix, and the fragrance of the stems 

 and leaves when bruised. — In water ; rare. — Fl. June, July. 

 Perennial. 



Ord. LXXXVI. Lemnace^e. — Duck-weed Family 

 A small group of widely-distributed, minute, green plants, 

 floating in standing waters, composed of leaf-like scales, with no 

 distinction of stem and leaf, generally with unbranched, thread- 

 like roots hanging downwards in the water, propagating themselves 

 principally by offsets, but sometimes producing 1 — 3 minute 

 flowers, which are monoecious, generally enclosed in a small, mem- 

 branous spathe ; perianth absent ; staminate flowers each of a single 

 stamen; carpellate-flower a i-chambered, 1 — 7 -ovuled ovary ; fruit 

 bladdery, indehiscent. 



1. Lemna. — Roots present ; flowers marginal ; spathe mem- 

 branous ; stamens stalked, with 2-chambered anthers. 



2. Wolffia. — Rootless ; flowers on the upper surface ; spathe 

 absent; stamens sessile; anthers 1 -chambered. 



1. Lemna (Duck-weed). — Minute, green, floating plants, with 

 simple or lobed scale-like fronds ; with thread-like roots; rarely 





