44, BRITISH MARINE ALG. 
remarkable of the rapidity of growth in marine algz on various parts 
of the coasts of England,—rocks, which in December were comparatively 
bare, being in April or May of the following year covered with Fuci of 
various kinds, Laminarie, and other species of alge. 
The Sporochnacee are a small but remarkably beautiful tribe of plants, 
six species only being found on the British coasts. Though chiefly 
characteristic of temperate waters, some of the species of this order are 
widely dispersed. Desmarestia viridis for instance, which is common on 
the shores of these islands, being found in the Antarctic Ocean, while 
Desmarestia ligulata (Fig. 51), also abundant on the British coasts, is found 
on the north-west coast of America, at Cape Horn, and at the Cape of Good 
Hope. Carpomitra Cabrere (Fig. 53c), which is said to be a native of New 
Zealand, is rare on our shores, being found only on the south coast of 
Ireland and in Plymouth Sound. These graceful plants are characterised 
as inarticulate olive-coloured seaweeds, whose spores are attached to 
external jointed filaments, which are either produced from the stems 
and branches in delicate tufts, or compacted together in long oval 
masses, some of which in early growth, as in Sporochnus, are terminated 
by pencils of thread-like filaments. As the plant advances in growth 
these delicate fibres fall away. In two species, Arthrocladia villosa 
(Figs. 58a and 54), and Desmarestia aculeata (Fig. 52), the summer 
and winter states of the plants are so widely different, that they are 
constantly mistaken for separate species, and deceived Linnzus himself. 
All the Sporochnacee, though of a delicate olive while growing, rapidly 
change to a verdigris green in drying, and have also the remarkable 
property of causing decomposition in all kinds of delicate alge with 
which they are placed in contact. Collectors who are aware of this pecu- 
liarity should be prepared with a separate vessel or bag, especially for the 
Desmarestia; for all the plants of this genus decay very rapidly, and it is 
impossible to display their beautiful tufts of pencilled filaments when 
once decomposition has set in. Whenever I have had the good fortune to 
meet with fine specimens of any of this group of plants, I have rarely 
loitered on the shore, or cared to look for anything else, but hastened 
home with my treasures and mounted them on paper as soon as possible 
Although, as observed by Dr. Harvey, there is so much similarity in the 
structure and habits of these plants, a peculiar difference in the organs of 
fructification has obliged botanists to break up this order into two 
families ; the first of which is Arthrocladia, the spores being attached 
to pencilled filaments which spring from the sides of the branches. First 
in this family stands the genus Desmarestia, named in honour of M. 
Desmarest, a French naturalist. It contains three beautiful species, 
which I will deseribe. 
It is very remarkable that no fructification has yet been observed on 
any of the Desmarestiew. Judging from analogy, one would expect to find 
it connected, in some way or other, with the lateral tufts of fibres 
abundantly produced in early growth : but until some fortunate discoverer 
