GLCEOCYSTIS. 



[ 359 ] 



GNETACE^. 



GLCEOCYSTIS, Nageli= Glceocapsa, pt, 



GL(EOSPO'RIUM,Montagne. A genus 

 of Sphaeronemei (Stylosporous Fungi), 

 developed beneath the surface of leaves, and 

 bursting through, forming a kind of rust on 

 the surface. 



G. paradoxum ( My xosporium paradoxum, 

 De Notar.) occurs on ivy. 



G. Lobes. Asteroma Lobes, Berk. Brit. 

 Fungi. 



G. concentricum (Cylindrosporum concen- 

 tricum, Grev. Sc. Crypt. Flor. p. 27) forms 

 a white rust upon cabbage-leaves. 



BIBL. Berk. & Br. Ann. Nat. Hist. 2 ser. 

 V. p. 455 ; Berkeley, Hort. Trans, vi. p. 121. 



GLCEOTHE'CA, Nag. A genus of 

 Palmellaceae (Confervoid Algae), distin- 

 guished by the oblong or cylindrical cells, 

 with thick, often lamellar envelopes. 



13 species ; on humid rocks (Rabenhorst, 

 Fl. Alg. ii. 60). 



GLGEOTILA, Kiitz. A genus of Con- 

 fervaceae with simple, submoniliform fila- 

 ments, endochrome of the cells becoming 

 contracted and rounded. Ten species. 

 Freshwater ; in ditches and aquaria. (Ra- 

 benhorst, Fl. Alg. iii. 319.) 



GLOIOSIPHO'NIA, Carm. A genus of 

 Cryptonemiaceee (Florideous Algae), the 

 single British representative of which is a 

 rare, feathery, red sea- weed, 3-12 inches 

 high, with a semigelatinous tubular frond. 

 The spores are in dense masses, scattered 

 among the radiating j ointed filaments which 

 clothe the periphery of the branches. 



BIBL. Harvey, Mar. Alg. 152, pi. 21 A, 

 Eng. Sot. pi. 1219. 



GLYCERINE is the sweet principle of 

 fats. It may be prepared by boiling fats 

 with oxide of lead and water. The aqueous 

 solutions are freed from the lead by sulphu- 

 retted hydrogen, the filtered liquid eva- 

 porated to the consistence of a syrup, and 

 finally in vacuo over sulphuric acid. It is 

 now procured by decomposing the fats with 

 high-pressure steam. 



Glycerine, when pure, is a colourless, 

 highly refractive, syrupy liquid, of a sweet 

 taste j it mixes in all proportions with alco- 

 hol and water, but it is insoluble in ether. 

 The property possessed by glycerine, of 

 constituting a liquid which does not become 

 dry, and mixes with water, renders it very 

 useful for the preservation of microscopic 

 objects 5 especially those which will not 

 permit of being dried, such as preparations 

 of vegetable structure, which may De left on 

 a slide in a drop of glycerine, with a glass 



cover to exclude dust, for weeks and months 

 without alteration. It renders objects very 

 transparent, which is sometimes advan- 

 tageous, sometimes the reverse. A solution 

 of gum-arabic in diluted glycerine is often 

 used for mounting objects which do not bear 

 drying. The solution is made by dissolving 

 1 oz. of very clear gum in 1 oz. of water, and 

 adding subsequently 1 oz. of glycerine: 

 great care must be taken, in incorporating 

 the glycerine, to avoid forming air-bubbles, 

 which are difficult to get rid of on account 

 of the viscidity of the fluid. The mode of 

 mounting objects is to soak them in pure 

 glycerine, and then to operate as with 

 Canada balsam, only not applying heat. 

 GL YCIPH' AGUS,Hering. A subgenus 



Of ACARTJS, p. 8. 



GLY'PHIS, Ach. A genus of Graphidei 

 (Lichenaceous Lichens). 



G. labyrinthica, on trees, very rare. 

 (Leighton, Lich.-Flora, 436.) 



GLYPHODES'MIS, Grev. A genus of 

 Diatomacese. 



Char. Fr. united into a filament ; side view 

 naviculoid, with a central nodule, median 

 line, and transverse rows of granules ; struc- 

 ture clathrate (?), the granules being deve- 

 loped within square areolae, arranged in 

 parallel rows. 



G. eximia. In scrapings of marine shells. 

 Jamaica. . 



BIBL. Greville, Qu,. Mic. Jn. 1862, 234 

 (figs.). 



GLYPHODIS'CUS, Grev. A genus of 

 Diatomaceae. 



Char. Fr. four-sided, the angles much 

 rounded. Valves with a large 4-angled 

 nucleus, the angles alternating with those 

 of the margin; and a circular prominent 

 process within each marginal angle, from 

 which costae radiate to the nucleus ; whilo 

 similar costae radiate from the angles of the 

 nucleus to the sides of the disk. 



G. stellatus. Monterey stone. 



BIBL. Greville, Mic. Tr. 1862, 91. 



GL YPHOMIT'RIUM, Bridel. A genus 

 of Orthotrichaceous Mosses, deriving its 

 name from the grooved calyptra. Glypho- 

 mitrium Daviesii, Brid., is found in Wales 

 and Ireland on rocks, mostly near the sea. 

 It is peculiar to Great Britain and Ire- 

 land. 



GNAT. See CTJLEX and CULICIB^E. 



GNETA'CE^E. An order of Flowering 

 Plants, remarkable for their jointed stems, 

 composed of ducts and wood-cells marked 

 like the wood of Conifers. The rind and 



