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 BOTANY chiefly in the neighbourhood of Penzance, the work has been done by one of the keenest and most careful botanists of the last century, viz. Dr. Ralfs, whose Monograph of the British Desmidiea, published in 1848, is, for lucidity of description and exquisite delineation of the forms of the species, unsurpassed even at the present day. The list of Cornish fresh- water alga? is therefore, especially as far as concerns the DesiauJiaceat, Diafomacece (now usually called the Bacillariacece) and Palmellaceee, un- usually rich as regards records. During the last quarter of the century the materials collected by Dr. Ralfs were carefully collated and added to by Mr. E. D. Marquand, who published an account of the freshwater alga? of the Land's End district in the Transactions of the Penzance Natural History and Antiquarian Society, ii. 133, 380. Other botanists who contributed to this record were Mr. J. B. Major ; Prof. O. Nord- stedt of Lund University in Sweden, who paid a visit to Penzance and detected a number of new species there ; Mr. A. W. Bennett, who searched the north of Cornwall, and Mr. R. V. Tellam, who collected some species in the neighbourhood of Bodmin. In the Land's End district Mr. E. D. Marquand indicates Chy-an-hal and Tremethick Moors as particularly rich in unicellular species, and the dripping rocks between Mousehole and Lamorna, and the coast between Lelant and Carbis Bay as yielding many species not observed elsewhere. The large number of species detected in this small portion of the county suggests that Cornwall is probably one of the richest counties in England in this group of plants, although it is possible that the mountainous counties near the sea, in Wales and the west of Scotland, might be richer in Alpine forms. That the list will probably be greatly extended in the future is shown by the fact that many species new to the county, and a few new also to science, are recorded in the "Journal of Botany for February and March, 1903. The following are the species new to science : Phaeosphaera gelatinosa, West & G. S. West Bumilleria pumila, n. sp. Ic. pi. 446, figs. 22,23 Conferva obsoleta, n. sp. Ic. pi. 446, figs. 18, 21 Cosmarium quadrimammillatum, n. sp. Ic. pi. 446, fig. 12 Debarya desmidioides, West & G. S. West, Ic. pi. 446, figs. 1-9 The species new to the county are : Bulbochaete subintermedia, Elfn. Sennen Closterium pusillum, Hantsch. var. monolithum, With. Gurnard's Head macilentum, Brdb. Mullion pronum, Br6b. Euastrum lobulatum, Brb. Tremethick Moor, St. Just, Sennen, Land's End Genicularia spirotasnia, De Bary. Hayle Cosmarium Lundelii, Delp. Mousehole abbreviatum, Racib. Crowan commissurale, Brb. St. Just Staurastram granulosum, Ralfs. Crowan brachycerum, Breb. Sennen vestitum, Ralfs. St. Just Zygnema Vaucherii, C. Ag., var. stagnale, Kirchn. Lizard Conferva affinis, Ktltz. South of Helston, St. Mary's, Scil/y Characiopsis minuta, Borzi. Penzance Centrosphsera Fasciolae, Borzi. Sennen Bulbochaete subintermedia, Ktltz. Euastropsis Richteri, Lagerh. }>