176 CXXXVIII. NAIADE X. [ Zostera. 
spatha, which otherwise resembles the stem-leaves. Rhachis of the 
spike broad and thin, with the margins folded inwards and bearing the 
flowers and fruits only on the inner surface. 
The genus consists of very few species, perhaps reducible to two only, common in 
most seas at or near the shores. The Australian i s 
end. 
other seas, although the common broader leaved variety of Z. marina has not yet 
turned up fr lian sea 
Floral sheaths 3 to $ in. long and scarcely above 1 line 
broad, the rhachis inside with a little transverse ver- 
a evita ma etis 2. Manas 
Floral sheaths nearly 1 in. long and 2 lines broad, the : 
t ppendages . . . 9. Z. tasmanea. 
Kı 
Leaves narrow-linear, rarely above 1 line broad, varying in length e 
a few inches to Lor 2 ft., usually truncate or notched at the end, with 
conspicuous central nerve and 1 or 2 lateral ones on each side often 
of the sheath but free from it, the margins folded inwards and bearing. 
just within the edge on each side 2 or 3 vertical plates folded inwards 
over some of the flo .—Z. marina, Hook. f. , R. 
Br. Prod. 338? partly; Z. Muelleri, Irmisch; Aschers. in Linn, 
xxxv. 168. 
Coasts of Victoria and S. Australia, F. Mueller and of Tasmania Gw" 
J. D. Hooker. 
e Australian form is distinguished by Ascherson and others from the Z. nana 
the northern hemisphere, chiefly by the apex of the leaf being truncate with à d 
i e, and narrow with a deep narrow notch in the other, but I fin 
differences as great in this respect between different specimens from the menores 
à where 
to vary in the number and shape of the inflected plates as well as in the foliage, one 
always find these plates just within the margin of the rhachis, as drawn in Nee 
Ge y marginal as they are usually described. 
2. Z. tasmanica, G. v. Mart.; Aschers. in Linnea, xxxv. ron? 
Foliage of the broader leaved specimens of Z. nana, or of the narrowes 
varieties of the northern Z. marina, the leaves rather above 1 line broad; 
