DICRANUM. 



[ 207 ] 



PICTYOSPH^RIUM. 



Fig. 174. 



DICRANUM, Hedw. A genus of Apo- 

 carpous operculate Mosses. 

 Dicranum undulatum, Turn. 

 D. spurium, Hedw. 

 D. scoparium, Hedw. 

 D. majus, Sm.=D. scoparium, Hedw. 

 D.falcatum, Hedw. 

 D. Starkii, Web. and Mohr. 

 D.fulvellum, Sm. 



D. hyperboreum, Sm.=D.fulvellum, Grev. 

 ex p. 



D. longifolium, Ehrh. 

 D. montanum, Hedw. = D. Scottianum, 

 var. montanum, Hook. 

 D.flagellum, Hedw. 

 D. Scottianum, Turn. 

 D. turfaceum, C. Miill. = D. flexuosum, 

 Auct. ex p. 



D.flexuosum, Hedw. 



D. denudatum, Er'u[.=Didymodon longi- 

 rostris, W. and Mohr. 

 See LEUCOBRYUM. 

 DICTYDIUM, Schrad. A 

 genus of Myxogastres (Gaste- 

 romycetous Fungi), exceed- 

 ingly elegant little plants, 

 growing upon rotten wood. 

 The peridium is excessively 

 delicate and the peculiar capil- 

 litium adherent to it, so that 

 when the spores are expelled, 

 the transparent case appears 

 like a cage, formed of the veins 

 alone. There are no filaments 

 mingled with the spores. D. 

 umbilicatum (fig. 174) is a 

 British species ; it is of a 

 brownish-purple colour until Dictydium umbi- 

 the spores are discharged, then licatum. 

 hyaline ; it is gregarious in its Ma ^ n - 25 diam - 

 habit of growth. 



BIBL. Berk, in Hook. Brit. Flora, v. 

 pt. 2. p. 317; Greville, Sc. Crypt. Fl. pi. 153; 

 Fries, Syst. Myc. iii. p. 164; Schrad. Nov. 

 Gen. p. 11, &c.; Corda, Icon. Fung. v. pi. 3. 

 fig. 36. 



DICTYOCHA, Ehr. The nature of the 

 curious bodies, of which the genus Dictyocha 

 consists, is unknown. They consist of a 

 single piece, hence they are not Diatomaceae. 

 This piece is siliceous and loosely reticular 

 or stellate. Perhaps they are spicula of 

 Echinoderinata ?. They are both marine and 

 fossil. 



Kiitzing enumerates twenty-nine species (?); 

 distinguished principally by the number of 

 external spines and internal areolae; they 

 vary in diameter from 1-1150 to 1-370". 



D. gracilis (PI. 18. fig. 46; a, perspective 

 view ; b, side view ; c, view from above). 



BIBL. Ehrenberg, Abh. d. Berl. Akad. 

 1838. 1839. 1840, and Eer. d. Berl. Akad. 

 1844. 1845; Kutzing, Bacill. p. 140, Sp. 

 Alg. p. 142. 



DICTYOLAMPRA, Ehr. A genus of 

 Diatomaceae. 



Char. Frustules single; no internal septa; 

 valves equal, cellular (apparently) in the 

 middle, the smooth margin radiate. 



D. stella. The only species. Probably a 

 Cyclotella ? Found among Polycystina from 

 Barbadoes. 



BIBL. Ehr. Eer. d. Berl. Akad. 1847- p. 54. 



DIPTYOPTERIS, Presl. A genus of 



Polypodieae (Ferns), deriving their name 



from the reticulated arrangement of the 



veins. 



DICTYOPYXIS, Ehr. A genus of Dia- 

 tomaceae. 



The species are referred by Kutzing to the 

 genera Pyxidicula and Coscinodiscus. 



BIBL. Ehr. Eer. d. Berl. Akad. 1844. 

 p. 267 ; Kiitz. Sp. Alg. p. 125. 



DICTYOSIPHON, Grev. A genus of 

 Dictyosiphonaceae (Fucoid Algae), represented 

 in Britain by a common branched filamentous 

 sea-weed (D. f&niculaceus), with the frond 

 growing from one to several feet long, of an 

 olive or rusty-brown colour. The fructifica- 

 tion at present known consists of ovoid 

 sporanges, imbedded in the cellular tissue of 

 the branches, lying lengthways ; they open 

 by a pore at the surface. 



BIBL. Harvey,Br. Mar. Alg.y. 40. pi. 7 D; 

 Greville, Alg. Brit. pi. 8 ; Thuret, Ann. des 

 Sc. nat. 3 ser. xiv. p. 238. 



DICTYOSIPHONACEJE, A family of 

 Fucoideae. Olive- coloured sea- weeds with 

 cylindrical branched fronds, the oosporanges 

 imbedded lengthways in the substance of 

 the frond, opening by a pore on the sur- 

 face. 



Synopsis of British Genera. 



I. Dictyosiphon. Root a minute naked 

 disk; frond cylindrical, branched; oospo- 

 ranges scattered irregularly, solitary or in 

 dot-like sori. 



II. Striaria. Root a minute naked disk; 

 frond cylindrical, branched; oosporanges 

 arranged in transverse lines on the surface of 

 the frond. 



BIBL. See the genera. 

 DICTYOSPH^RIUM, Nageli. See 

 PALMELLACE.E. 



