38 : FLORA OF TASMANIA. | Zyphacee. 
Semina erecta v. horizontalia; festa membranacea. Embryo exalbuminosus, orthotropus v. semi-antitro- 
pus; cotyledone crassa, farinacea, inferne excavata, radiculam includens, infra centrum plumulam minimam 
involvens, tubo membranaceo globulis repleto percursa.—Herbe minima; frondibus lenticularibus, aquis 
dulcibus natantibus, marginibus proliferis; radiculis simplicibus, calyptra majuscula terminatis. 
A genus of very curious minute water-plants, found all over the temperate and tropical parts of the globe, 
familiar as “ Duckweed,” covering the surface of stagnant fresh-water with a pale bright-green stratum.— Fronds 
scale-like, proliferous at the margin, furnished with tufts of thread-like, solitary, or tufted roots that have thick- 
ened extremities. Flowers very minute, and seldom produced, included in slits of the frond, enclosed in a mem- 
branous spathe that bursts irregularly. Stamens two, exserted, unequal, with two-lobed anthers.— The flowers, 
which are, when present, detected with difficulty, from their excessive minuteness, may best be found by examining 
the yellowish patches of the floating stratum. (Name, the old Greek one.) 
l. Lemna minor (Linn. Sp. Pl. 137 6); frondibus ovalibus utrinque planis, radicibus solitariis.— 
Br. Prodr. 345; Fl. N. Zeal. i. 239. (Gunn, 1015.) 
Has. Still waters, abundant.— (v. v.) 
DIsrRIB. Australia, New Zealand, throughout Europe, Asia, North and South Africa, America, and 
the Pacifie Islands. i 
Fronds nearly ovate, compressed, 1-2 lines long, rather thick and succulent in texture, very slightly convex 
below. Roots solitary, Utrieulus one-seeded.— Lesser Duckweed” of England. 
2. Lemna trisulca (Linn. Sp. Pl. 1376); frondibus lanceolatis petiolatis eruciatim coherentibus, 
radicibus solitariis.— Br. Prodr. 345. (Gunn, 1014.) 
Haz. Still waters; less frequent than Z, minor, Brown, Gunn, ete.— (v. v.) 
DIsrarB. Australia, Europe, and various temperate and tropical countries. 
The * Ivy-leaved Duckweed ” of England.— Fronds 2-3 inch long, thin, elliptic-lanceolate, with one extremity 
prolonged, the other serrate, pellucid at the margin. Roots solitary. Seed solitary, transverse, with a short funi- 
culus. 
Nar. On». VII. TYPHACEA. 
The small Order to which Typha belongs, may, along with Pistiacee, be reduced to a section of 
Aroidee. The only genera belonging to it, Typa and Sparganium, are both Australian, though the former 
only has hitherto been found in Tasmania. 
Gen. I. TYPHA, ZL. 
Flores amentacei. Amenta cylindrica, mascula et feeminea eundem culmum vestientia, masculo supe- 
riore. Flores densissime congesti, papposi :—Masc. Perianthium 3-setosum, staminibus 3-6, filamentis 
filiformibus liberis v. varie monadelphis, antheris basifixis 3—Fam. Ovarium 1-loculare, longe stipitatum, in 
| stylum elongatum gracilem, apice lateraliter stigmatosum angustatum, stipite setis capillaribus (perianthio) 
b'umoso; ovulo unico, pendulo, anatropo. Utriculus evalvis, monospermus. Semen pendulum; testa 
membranaceo, albumine farinaceo, embryone axili, radicula hilo proxima, plumula fissura lateral; inserta, — 
Herbe; rhizomate repente, fibras crassas emittente ; foliis ensiformibus, subspongiosis, integerrimis; culmis 
inarticulatis, cylindraceis. 
This genus contains the common English Reed-mace, or “ Cat's-tail,” 
on the margins of fresh-water ponds, etc., where it is conspicuous for the cylindrical, bright-brown catkins of pap- 
pose flowers. These yield an immense quantity of pollen, which is 
* 
