BOTANY 



minute, and in order to obtain these some advice is necessary as they are not visible to the 

 naked eye ; these forms are often found about the stems and leaves of constantly submerged 

 plants, such as Utricu/aria, Myriophyllum, Nuphcr, Nymphaea^ Potamogeton, Sphagnum, &c. 

 To collect from plants like these it is best to remove them (or parts of them) from the water 

 with as little mud as possible and allow them to drain for about a minute, after which they 

 should be gently squeezed over a wide-mouthed bottle. Gatherings made in this way are 

 usually very rich in minute species. 



FRESHWATER ALGAE 



Only a moderate number of species have been noted as yet from the county ; this is due 

 to lack of local workers during recent times, most of the records being old ones. Excluding 

 diatoms, not more than forty genera and less than seventy species have been recorded. The 

 districts about Tuddenham, Bradwell, Belton, Bury, Lound, and Ipswich, would certainly 

 yield further results if worked. Among these recorded plants is the beautiful netted-purse 

 plant, Hydrodictyon utriculatum, found at Bungay and other places. About ten genera of 

 unicellular plants, excluding diatoms and desmids, are known to occur ; these include the 

 pretty coenobial genera Scenedesmus and Pediastrum. Volvox globator is frequent, and V. aureus 

 is probably present ; the latter can be distinguished from the former by its smooth spores and 

 smaller size. The Conjugatae are represented by seven genera including the Desmidiaceae, 

 only four genera belonging to the latter being recorded. The genus Vancherla is well 

 represented, by six species, including V. dichotoma, which is seldom absent from maritime 

 counties. The beautiful orange-coloured aerial algae, Trentepohlia {Chroolepus) aureum occurs 

 on trees. The two British species of the delicately-branched genus Draparnald'ia are frequent. 

 The gelatinous genus Chaetophora is represented by two species. As only two or three species 

 of the Oedogoniaceae are known to occur, it is evident that more work can be done in this 

 group. The remaining genera of the green algae which are known are those of common 

 occurrence. 



The blue-green algae usually known as the Cyanophyceae (Myxophyceae is an earlier 

 name) are represented by about fourteen species under eight genera, the genus Oscillatoria 

 being represented by seven species. 



The only freshwater algae belonging to the Red Algae that are recorded are Batracho- 

 spermum monUiforme and B, vagum, both very elegant species, and a species of Lemanea. 



DIATOMS 



This well-known group of plants includes both freshwater and marine species, as well as 

 some that are usually only found in brackish water, or sometimes in the latter as well as in 

 freshwater, or, in the case of some species, in either marine or brackish water. These are 

 unicellular plants of very varied form ; they occur wherever water is constantly found ; they 

 differ from all the other algae in having their cell-wall impregnated with silica, which prac- 

 tically renders them — as regards their form and markings — indestructible, hence large fossil- 

 deposits of them are found which are used commercially for various purposes, one important 

 one being in the preparation of dynamite. The cell-walls are beautifully and symmetrically 

 sculptured, although they are extremely thin. A fair number of species are known for the 

 county, about 200 species under about fifty genera ; this includes the strictly maritime species. 

 The genus Gyrosigma {Pkuroslgma), with its finely marked cell-walls, is well represented by 

 twenty species. Under the genus Navicula (including Pinnularia) about forty species are 

 recorded, and for the genus Nitzschia about twelve species. The genera Stauroneis, Gom- 

 phoncma, and Synedra, are represented by from four to six species each, while the genera 

 Surirella and Epithemia have eight and five species respectively, the genus Amphora also having 

 five. None of the other genera are represented by more than four species, the genera 

 Campylodiscus, Eupodiscm, Cocconeis, and Amph'iprora, have each several species. Fewer species 

 are recorded for the genera Cymbella, Coscinodlscus, Actinocyclm, Cydotella, Tryhlionella, Cymato- 

 pleura, Cocconema, Doryphora, Podosphaenioy Rhiphidophora, Aferidion, Bacillaria, Odontidium, 

 Fragi/aria, Achnanthes, Achnanthidium, Rhahdonema, Diatoma, Grommatophora, Tahellaria^ 

 Amphitetras, Biddulphia, Podoiira, Melosira, Orthoura, Maitoglota, Encyonema, Colletsnema, and 

 Schizonema, the species recorded usually varying from one to three. 



75 



