30 NAIADACEA 
contain a farinaceous substance. The lower part of the stem, which is often 
tinted with reddish-brown, is of a sweet flavour. This Grass-wrack is very 
abundant on some parts of the coast ; on those of Yarmouth, it is torn up by 
the waves, and strewn so profusely, that mounds are formed of its blackened 
stems and leaves for the purpose of resisting the encroachment of the sea. 
Mr. Gosse, describing the shores of Weymouth, says, ‘‘ Between tide-marks 
the pebbles are washed clean by the surf, but along the line of high water 
there is a broad bank of black Sea-grass, the accumulation of years, perhaps 
ages, rotting into mould, and forming an admirable manure. It is, indeed, 
used for this purpose, being carried away by the farmers, where it is suffi- 
ciently abundant and sufficiently accessible. In the vicinity of Torquay and 
of Ilfracombe, I had not met with this substance in any appreciable quantity, 
but in Poole Harbour, the scene of my early life, I had been familiar enough 
with it, as its dirty littering banks, like a continuous dunghill, fringe the 
shores, the refuse of hundreds of acres of the grass that grows on the muddy 
flats of that land-locked harbour.” 
Both in Sweden and Holland this Sea-grass is very extensively used as a 
manure, and is preferred to hay for filling mattresses. It is sold in England 
by upholsterers under the name of Alva marina, which is probably a cor- 
ruption of Ulva. It is sometimes used for thatch, and is said to last more 
than a century, often becoming quite bleached by exposure to sun and air. 
In sea-coast towns it is collected from the shore for packing earthenware and 
glass; and the rush-like coverings which surround the Italian liquor-flasks 
are made of this plant. Cows refuse to touch it, but it is eaten by horses 
and swine. Hugh Miller remarks of the Grass-wrack, that it is very sus- 
ceptible to frost, and he says that he has seen large quantities nipped by it. 
The French call the plant La zostere, and the Germans, Seetang. A slender 
variety, growing in mud, with about half the number of nerves in its leaves, 
is sometimes termed Z. angustifolia ; and a small plant, scarcely three inches 
long, with slender leaves, which have but one nerve, is described as Z. nana. 
Some botanists doubt if the three plants are truly distinct. In this dwarf 
Grass-wrack the nuts are described as smooth, while in the other kinds these 
are marked with fine lines. The dwarf plant grows in muddy salt-water 
pools in estuaries, but is rare. 
5. Naras (Navas). 
1. Flexible Naias (N. jlexilis).—Stem thread-like, branched ; leaves 
very slender, linear, with fringed sheaths, opposite or in whorls of 3 ; flowers 
solitary, or 2 or 3 together; berry one-eighth of an inch across. This is a 
very slender submerged perennial with brittle stems, and inconspicuous male 
and female flowers on the same plant. It flowers in August and September, 
and has been found in lakes in Perthshire, Skye, and Connemara. 
2. Greater Naias (NV. marina).—Stem branched sparingly, with a few 
teeth ; leaves with strong spiny-teeth and entire sheaths; flowers solitary, 
the males and females on separate plants; berry, a quarter of an inch in 
diameter, purplish. This plant, which flowers in July, has been found in 
Hickling Broad, Norfolk. It is also known as N. major. 
