THE SEA-WEEDS AT HOME AND ABROAD. 285 
Some tropical sea-weeds belonging to this section now 
claim the attention. These are the Siphonaces, so-called 
beeause whatever be the form or size of the alga the different 
parts have a continuous cavity throughout like a pipe or 
siphon. And a very great difference exists in these several 
forms, some of which are very singular, others very beautiful. 
They are described as green, marine or fresh-water alge, 
either naked or else coated with carbonate of lime, which 
they extract by the method of their growth and life from the 
water. A few kinds, of which the elegant Bryopsis is an 
instance, are found in our northern bays and waters. It is a 
pretty little ereen-tufted feather-like alga, parasitic on other 
weeds, and growing on the rocks near the shores. Yet in 
its range it reaches to Cape Horn, the Falkland Islands and 
New Zealand. The green particles within its substance 
break up into smaller parts, and bursting through the sides 
of the branches escape to furnish the needed seed dispersion. 
In a somewhat similar branching kind, but in which the single 
jointed filaments and branchlets or twigs, as we may call 
them, are compacted together into flattened bundles, so as 
to look like a rude fan furnished with a handle or stem, and 
the sticks somewhat encrusted with carbonate of lime, we have 
the Udotea, named by Lamouroux after some ocean goddess, 
known to Hesiod. One species, the U. conglutinata, of 
Lamouroux, has been seen growing at Key West; and 
another, in which the lime is uniformly and evenly depos- 
ited on the entire surface, much more resembles a spread- 
out fan, and is known in our tropical seas as U. flabellata, 
while other seas produce still other forms. They are so 
bizarre and unlike ordinary alge that no one but an adept 
would recognize their place among sea-weeds. In Halimeda 
(fig. 74) we have still other singular and anomalous looking 
plants, short-jointed and broadly dilated for the length of 
the joints, looking not unlike some smaller truncated cactus 
of the green-house, but soon fading to a dull white tint, and 
on drying becoming brittle. Several species are met with 
