ALGjE. 17 



thoucli intlividually so niiimte, immense hcds of rock, many foot in thickness, are 

 found to consist, mainly if not entirely, of the persistent remains of these wonderful 

 organisms. Some sj)ecics, as UaciUaria, have an apparently spontaneous motion, 

 being seen to move backwards and forwards, in a jerky manner, in the field of tho 

 microscope. Hence their claim, in the opinion of some, to a place in tlic animal 

 kingdom; "but," observes Mr. Berkeley, "it is now well known that even active 

 motion is not inconi|)atihlo with tho nature of vegetables"; and, "Mr. Half's 

 discovery of the formation of spores by conjugation in several genera has etfcctually 

 put an end to controversy." 



Stagnant pools, ditches, running streams, the trunks of trees, wet stones and 

 rocks, damp paths and walls, and the surface of mud are all liabitats of Diatomacea). 



The duration as living species and the ubiquity of the lower as compared with 

 the higher fonns of vegetable life is a remarkable peculiarity. While no remains 

 (I believe I am correct iu saying) of I'hsnogamous plants, nor of the higher 

 cryptogams, specifically identical with forms now existing, have been discovered 

 in a fossil state, except in strata of very recent formation ; on the other luxnd, many 

 of the siliceous skeletons of Diatomaccoe, of which the Tripoli of Bilin iu Bohemia 

 is mainly composed, are found to be identical with those of species now living 

 on the earth ; and this rock is referable to tho Eocene period. The specific life 

 of some of the minutest vegetable organisms is thus proved to be of immense 

 duration. So of their ubiquity. The area within which the same species of any 

 Pha?nogamous plant is found growing indigenously, though greater or less acconliiig 

 to circumstance, is markedly limited ; but cryptogamous jilaiits, specifically identical, 

 are found contemporaneously in the most distant parts of the world, and under tho '/ •-■,■" ^'" 

 most dift'ereut climatic conditions. s^r''^'''^-^' 



" • Ko tree, or shrub, or herbaceous plant is found at once in Britain and in Burmah : i ,^--. l ■' 



' kindred forniff may indeed be found, but not identical forms : we have, for instance, 



JIdbeiiarins among Orchids, in both countries, but they are specifically distinct. It 

 is otherwise, however, when we leave flowering plants and descend to non-flowering 

 plants. On coming to Fenis, we at once find identity of species ; and, as we descend 

 to lower and still more lowly organized forms, the instances of identity increase 

 in number. For example (to confine illustrations to Burma), among ferns, Jli/meno- 

 phyllum Tunbiidgieme, Adianfum Capillits J'oieris, Pteris aquilina and Aspidixtm 

 aculeatum may be gathered both in England and in Tenasserim : while another fern, 

 > . Agiopteris erecta, a Burmese species, ranges from Japan to Madagascar, and grows also 

 in the islands of the Pacific Ocean. 



Among mosses, I have gathered the following British species in Bumia : Weissia 

 tenuirostris{ = Torluhi cylindrica), Funaria hij/irometrica, Bryum roseum, Finsidoii bryo- 

 ides, Foflonatum aloides, and Sphaynum acutifuUum : and there are doubtless many more 

 to bo added to the number, wlion the mosses of the country come to be thoroughly 

 investigated. Besides the above-mentioned British species, there may be gathered, 

 within a mile of Maulmain, a small moss, Scliistomilrium Gardnerianum, first found 

 on the Andes of Quito ! 



To come to the Algoe. In the list of the species collected by Jfr. S. Kurz, 

 I recognize as British, Spirogyra {Zyynema) quiniiia and S. dccimina (these two 

 species are frequent in clear pools on commons and similar places in Englanil) ; 

 Euaslrum ampuUaceum and anstdum ; Closteriiwi striolatum : to which may Ik; added 

 Laurcncia obliisa; CatcneUa opuutia; Enteromnrpha conipressa and intestiiutlis; Lynybya 

 majuscula ; probably, also, many more, which, from my slight acquaintance with 

 the subject, I am unable to specify.' 



1 After the above remark.s were written, and while tiirnins; over the leaves of Lyell's Principles 

 of Gcolci^'V to verify the correctnes.s of my statement that ' Tripoli ' is referal)le to the Eocene period, 

 I came, singularly enoui;h (Vol. II. p. 390), upon the foUowinf,' observations: — 



" The fact of the uhicjuitous character of cry])to;^amous plants deserves special attention. Linn.TUs 

 obsened that, as the germs of plants of this class, such as mosses, fungi, and lichens, consist of an 

 impalpable powder, the particles of which are scarcely visible to the naked eye, there is no dilliculty 

 in accotmting for their being dispersed through the atmosphere, and carried \c every point of tlu' globe 

 where there is a station for them." And the examples given by him are these — "No less than 200 



