May 20, 1875] 



NATURE 



57 



during different periods of their development, and this more fre- 

 quently in an analogous manner. During the first period they 

 are so like each other that it is almost impossible to separate one 

 from the other the younger forms of the most dissimilar species. 

 They all begin with a short stalk and an undivided frond (lamina) ; 

 then the stalk continues short in some, and lengthens consider- 

 ably in others ; in some the lamina continues undivided ; in 

 others it is cloven. But it is especially to be; observed that 

 this lamina, whether undivided or cloven, is variable in most 

 species. Thus, all are at first small and extended in length, 

 with a more or less wedge-like base ; but the wedge-like base 

 becomes heart-shaped and even kidney-shaped in some ; in others 

 it retains a wedge-like form throughout its whole state of deve- 

 lopment. Most species periodically change their lamina ; with 

 the change the new lamina becomes larger and broader than the 

 old one. The young lamina is thin ; in colour rather inclining 

 to green than to light brown ; in different species the lamina is 

 at a later period thinner or thicker, and with a different tint of 

 colour. The fructification appears in different species not only 

 in different parts of the lamina, but the sori extend in different 

 directions, although they do not seem to assume precise forms. 

 The characteristics of species must therefore be judged, not 

 Irom the peculiarities of appearance, but by the whole develop- 

 ment of the plant, the differences of which are with difficulty 

 comprehended, unless the species throughout their whole range 

 of growth be accurately compared with each other. Considering 

 that certain characteristics are scarcely perceptible except when 

 the plants are in fresh condition, and that collectors are contented 

 with preserving portions or incomplete specimens only, we 

 cannot wonder that the species of Laminaria should be confounded 

 with each other. 



Greville had named a Laminaria from the coast of Africa, 

 L- pallida, from a modification in its colour. Younger forms, in 

 which the colour was less evident, or the lamina not yet cloven, 

 were referred by many algologists sometimes to Z. digitata, some- 

 times to L. saccharina. But between these northern species and 

 that of the Cape, lies an ocean which it is difficult for a Laminaria 

 to pass. Although the characters which separate Z. pallida and 

 L digitata are not more important than those which separate 

 Z. digitata from Z. steiiophylla, it naust, nevertheless, be consi- 

 dered that Z. pallida is a distinct species. 



Z. longicruris is the most common as well as the largest of 

 the Greenland Laminarise. It is the representative on their 

 coast of Z. caperata, a native of Spitzbergen, no specimens of 

 which have been seen from Greenland, neither has Z. longicruris 

 yet been found at Spitzbergen. From Greenland Z. longi- 

 cruris spreads down the American coast as far at least as the 

 forty-second parallel, and one specimen is reported from the 

 Bahamas. Portions of this species have been cast ashore on 

 the coasts of Norway, Ireland, and Scotland. In Gunner's 

 " Flora Norvegica," a form is mentioned under the name of Ulva 

 maxima, which Agardh considers to be Z. caperata ; the same 

 Jorm has also been found on the north coast ot Scotland. 



The Berggren collection also contained a gieat number of 

 examples of Laminaria that, by Dickie (Alga; from Cumberland 

 Sound, in Linn. Soc. Journ. vol. ix. p. 237) and by Croall (in 

 Brown's " Flora Discoana," Trans. Bot. Soc. Edinb. p. 459), 

 was called Z. saccharina. Prof. Agardh considers the above- 

 mentioned plant as identical with his Z. cuneifolia. He states 

 that he has never seen a specimen from Greenland of Z saccha- 

 rina as it appears on our coast. Z. cuneifolia is an example of 

 a species which is found near Greenland and also in the northern 

 part of the Pacific. The "Alga described by Ruprecht under 

 the name of Z. saccharina v. lessonio'/olta mzy be a smaller form 

 of the same species. Specimens from Newfoundland and Scot- 

 land have been seen, which may belong to the same species. * 



Of Z. solidungula' there are specimens from Ritterbank and 

 Jakobshavn, This species seems to have a wide range in the 

 Arctic sea, appearing at Spitzbergen, Greenland, and in the 

 northern parts of the Pacific, if, under this species, is to be 

 accepted some specunens with disciform roots described by 

 Ruprecht. 



In the same collection is a new species with laciniated frond, 

 named Z. atro-Julva from its dark colour, which distinguishes it 

 from every other species, in all stages of its growth. Excepting 

 Z nigripes, it is the only Laminaria from Greenland with a laci- 

 niated frond. Neither Dickie nor Croall mentions it in their lists 



* Near Walrus Island, lat. 74° N , great quantities of marine plants, 

 chiefly consisting of a large Laminaria, were washed up by th« ice and the tide, 

 or were lying in hollows. See Nairative of North German Expedition, 

 vol. ii. p. 518.— M. P. M. 



of Alga;. In a note to the Flora Discoana it is mentioned that 

 in another collection Z. digitata was found. From such a 

 statement one may, nevertheless, be unable to determine which 

 Laminaria with laciniated lamina was here referred to. That 

 Z. digitata, so common on the European and Spitzbergen coasts, 

 should not be found in Greenland was so much the more singular, 

 that it was thought to be common at Newfoundland, and is 

 stated by Harvey to appear on the American coast as far south 

 as Cape Cod. Postel and Ruprecht also mention it as existing 

 in the North Pacific, but perhaps the specimens seen belong to 

 other species. Z. Bongardiana, with which Z. atro-fulva most 

 nearly agrees, is said to have a canaliculated stem, by which it 

 is easily separated from the Greenland species. 



Of Z. dermatodca there is only one specimen in this collection. 

 It is probably rare in Greenland. This species is found at New- 

 foundland, Spitzbergen, and Norway. 



Z. Fascia is included in the Berggren collection, but is not met 

 with at Spitzbergen. * 



A Greenland specimen, called Scytosiphon filum, was in a 

 state of preservation too imperfect to be determined. 



The most beautiful and characteristic species of the Greenland 

 marine flora are, undoubtedly, those of Agarum, a genus which 

 belongs also to the northern part of the Pacific. The Greenland 

 species extend down the North American coast and that of 

 Newfoundland, but not a fragment of this genus has as yet been 

 found on the Spitzbergen and European coasts. It appears 

 to be common in Greenland. The Greenland species vary in the 

 breadth of the costa and the closeness of the holes with which 

 the frond is pierced, but Agardh knows of no other difference, 

 and refers all the specimens to one species, namely, A. Turneri. 



Among the Laminaria;, included in the collection, few are of 

 greater interest than the form of Alaria taken in Sukkertoppen 

 in great abundance and of all ages. Hence Prof. Agardh has 

 been able to characterise the different Greenland species of Alaria, 

 which are as follow : — A. esculenta, A. musajolia, A. Fylaii^ A. 

 vtembtanacea, and A. grandi/olia. 



Next to the Laminariae the Fucaceos form the most consider- 

 able part of the Berggren collection. They consist chiefly of 

 the more Arctic forms.brought home from Spitzbergen, with some 

 differences. Of the forms common on the north coast of Europe 

 {Fucodium canaliculatum, Fucus serratus, \IIalidrys siliquosa) 

 which have not been found on the coast of Newfoundland or 

 America, there are not any examples in the Greenland col- 

 lection. Of these, F. serratus only is found at Spitzbergen, but 

 this differs from the true European form. With F. serratus 

 may be compared F. edentatus of Newfoundland, F. canalt- 

 culatum was compared by Harvey with F, fastigiatum of 

 California. Analogous species probably represent each other in 

 different localities. Of fucodium nodosum, some examples, 

 taken from different localities, are foimd in the Greenland 

 collection. 



Fucus vesiculosus, so common along the European coast even 

 up to the extreme north of Norway, is absent, or at least very 

 scarce, at Spitzbergen, but is one of the commonest of the Green- 

 land species. It is found there both with and without vesicles. 

 Besides F. vesiculosus, the collection contains numerous ex- 

 amples of Z! evanescens, J. Ag., F. Miclonensis, and F.filiformis, 

 which grow together, and in the same locality as F. vesiculosus, 

 which is distinguished from the others by its stout consistence 

 and by its drier surface, while the others give out more mucus. 

 It is also easy to separate extreme forms of F. ez^anescens, F. 

 Aliclonensis, and F.filiformis, but among the abundance of speci- 

 mens brought from Greenland intermediate forms appear, so that 

 it is often difficult to decide the boundary between these species. 

 When extreme forms lie together, F. fihformis, so different in its 

 aspect from F. evanescens, is without doubt much more nearly 

 related to F. evanescens than to F. distichus, with which it has 

 long been confounded and considered identical. 



Among the Greenland collection is one which differs from any 

 that Prof. Agardh had seen, but which agrees most nearly with 

 F. fili/ormis, although it is separated by fixed characters from all 

 the species previously received. The smallest forms come 

 nearest to Z. balticus, like that forming globular vesicles which 

 probably float the plant with ease into deeper water. It has been 

 named F. divergens. 



The fact that the species of Fucus, more than those of various 



*In the narrative of the German Arctic Expedition (vol. ii, p. 345) Z. 

 Phyllitis is stated to have been found all along the East Greenland coast 

 among and under the ice. This is the first time I believe that this Alga has 

 been reported from so high a latitude. It was accompanied by Dtsmarestia 

 aculeata.—'UL. P. M, 



