A(z 
156 ; CRYPTOGAMIA ANTARCTICA. | Puegia, the 1 
plane, and it often depends on the smoothness of the water how long they may remain so. This variety is abundant i 
everywhere in the Antarctic seas. " 
Variety y. angustifrons. The character, drawn from the tenuity of the vesicles, is utterly unsatisfactory, being : 
attributable to the drying of the specimen, and the locality of the live plant. Besides the Antarctic habitats of " 
this variety, it has been found in Chili, New Zealand, and the Indian Ocean. à 
Varieties e. luxurians, and ¢. membranacea. If any form of this genus deserves specific distinction it is surely m 
the noble one we have designated e. luxurians; and yet permanent characters, distinguishing it from pyrifera, were 
vainly sought in plants gathered on the shores of Berkeley Sound. Both there and at Cape Horn these two states 
inhabited deep and still waters, where, as might be expected, the Macrocystis would acquire its greatest develop- » 
ment, where its substance would be most membranous, its stems most slender, and the vesicles broad with thin walls, | l P 
and the base of the frond broadest. We have seen no specimens of these varieties except what were brought home ۱ 0 
by the Antarctic Expedition. A 
Variety y. Humboldtü, at first sight appears different, and the specimens found on the outer shores of the | - 
Falklands we once thought might belong to a distinct species. The rounded form of the vesicles, however, which a i 
affords the main character, is not constant on specimens collected in the Coral Islands by Captain Beechey. It n oft 
has been gathered at various places along the west coast of South America, from Cape Horn to the Equator, and a dà 
far westward in the Pacific amongst the Coral Islands. : ۱ The 
With regard to other states, which we have not seen, the most remarkable is the M. Orbignyana of Montagne Seba 
(Sert. Patagon. p. 12. t. 1.), which has the vesicles remarkably lengthened and the leaf attenuated at the base above | the 
the vesicle into a distinct petiole. The M. latifolia, Bory, is intermediate between our e. luxurians and pyrifera. f | " 
M. tenuifolia, Post. and Ruppr., is apparently between M. pyrifera and M. zosterafolia. The character of M. plani- uà 
caulis is founded on the compression of the stem, produced by drying, and we have therefore quoted it as a vig 
ERDE: i sho 
In thus bringing together under one, the ten species which have been described by five authors, of whom hardly | Fos 
one has ever seen even the genus in a living state, we are only taking advantage of opportunities which a long | the 
residence in the Southern Hemisphere has afforded. Without studying these plants on the coasts they inhabit, it is | 
impossible to judge of the influence of local causes on their plastic forms. We venture to say that few botanists 
in Europe have seen even tolerable specimens from one single plant of this Alga, such, we mean, as give a fair ia 
idea of the differences between the leaves and bladders, along, perhaps, 300 feet of stem, with the submerged m 
fructifying fronds from the root. Out of some thirty specimens brought home by ten different collectors and J 
preserved in the Hookerian Herbarium previous to our visit to the seas which M. pyrifera inhabits, not one ۳ 
conyeys any notion of the variations which even a solitary individual can assume. ۳ 
The fructification of this plant appears to be produced only on the young newly-formed submerged leaves, : ۳ 
where it forms large irregular brown patches or sori, causing the frond to separate into two lamine, as in Lessonia. y ۱ 
The spores are fusiform, first divided into four, each afterwards breaking up into as many sporidia. Under a high ha 
power the surface of the fertile frond is seen generally to be covered with anastomosing raised lines of a dark colour, , 
on which the spores are placed; the spaces between are pale and transparent. We have not noticed spores, "n 
like what are figured by Agardh (l.c. t. 28. f. 11), but plenty of the kind he represents at f. 10° of the same 
plate, though not contained in sporangia. These, magnified as highly as his f. 10°, are evidently divided, as in of t 
D'Urvillea. The granules also, which occur abundantly with the spores, are surrounded by a hyaline border, and | atte 
divided into two to four sporidia; we suppose them to be merely small spores. odil 
It is seldom that the history of an Ælga is likely to. afford interest or amusement to the general reader, unless the 
it be a positively valuable plant in an economic point of view. Like the Sargasso-weed of the Tropics, however, Tha 
the Macrocystis i is so conspicuous, and from its wandering habits, often occurs so unexpectedly, that the attention hav 
of our earliest voyagers has been directed to it, and we are consequently led back by our enquiries into its first | that 
