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 BOTANY Sclenastrum gracile, Reinsch. Puttenham Hapalosiphon intricatus, West. Puttenham Common Common Lagerheimia genevensis, Chodat. Mill Pond Lyngbya putealis, Mont. Richmond Park east of Chapel Wood srugineo-ccerulea, Gom. Esher to Kingston Tetrafidron horridum, West and G. S. West. versicolor, Gom. Dorking A species new to science; Puttenham Phormidium molle, Gom. Growing on Common Myriophyllum in Richmond Park Characium Pringsheimii, A. Br. Barnes and foveolarum, Gom. In a chalk pit at Mitcham Commons Dorking Ineffigiata neglecta, West and G. S. West. tenue, Gom. Wimbledon and Bisley Com- The genus itself is new to science ; the mans species occurs on Thursley, Esher West- Oscillatoria prolifica, Gom. Ranmore Common end and Puttenham Commons, also at in a pond Mill Pond east of Chapel Wood simplicissima, Gom. Wimbledon Common Stichococcus dissectus, Gay. Occurs on damp angustissima, West and G. S. West. walls about London Wimbledon Common Trochiscia aspera, Hansg. Wimbledon Common Polycystis flos-aquae, Wittr. Thursley Common stagnalis, Hansg. Chobham Common No less than thirty species of Desmids have been found with zygospores ; this proves that the conditions and places are often suitable for their production. The total number of species which have been determined is nearly 500, in addition to which the writers have noticed several hundred species of diatoms. Batrachospermum vagum (Florideae) is a large and graceful alga which feels like frog-spawn, hence its generic name ; it can be recognized without the aid of a microscope ; it occurs at Devil's Jumps, Frensham, as well as in boggy pools at Thursley Common. Three species of Coleochcete occur C. orbicularis at Crowhurst, C. soluta at Fren- sham and Bisley, C. scutata being more widely distributed ; the species of this genus are usually found attached to larger submerged aquatic plants. Three species of Bulbochaete occur, B. mirabilis being of the most interest, from Thursley Common. Monostroma bullosum is an uncommon species ; it occurs on Mitcham Common. So many good species of Desmids occur that it is a difficult matter to select certain of them for special mention. Penium spirostriolatum, P. curtum and P. interruptum are fine at Puttenham Common ; the last also occurs at Thursley Common, and a large form in the Mill Pond east of Chapel Wood. The charac- teristic and uncommon P. rufescens is found on Bisley Common. Other rare species of Penia are polymorphism from Chobham Common, incon- spicuum from Puttenham Common, cucurbitinum from Thursley Common, and cruciferum from Wimbledon Common. Many species of Closterium occur : Malirrvernianum at Esher West-end Common and Frensham, pseudodiance at Thursley Common, Cynthia and regulare at Puttenham Common, directum at Esher and Mill Pond east of Chapel Wood, Ralfsii var. hybridum and setaceum at Puttenham and Thursley Commons, and Ceratium on Esher and Wimbledon Commons. The genus Euastrum is well represented and the following good species are worth enumerating : affine and insigne at Chobham Common, pyramidatum, inerme, sinuosum, ventricosum and cuneatum at Thursley Common, erosum var. notabile at Bisley Common. The rarer species of the beautiful genus Micrasterias 59