DICOEYNE. 



[ 259 ] 



DICTYOCHA. 



D. capreohts (PI. 18. figs. 63, 64); D. an- 

 tennata (PI. 18. fig. 61) ; D. bulbosa (PI. 18. 

 fig. 62) ; D. dathrata (PI. 18. fig. 65). 



BIBL. Ehrenb. Bert. Ber. 1844, 73, and 

 Mikrogeologie ; Bailey, Sillim. Jn. 1856; 

 Greville, Mic. Tr. 1865, 56, 98. 



DICORY'NE, Allm. A genus of Hy- 

 droid Polypi, fam. Atractylidae. 



D. conferta. On old shells, Buccinum, &c. 



BiBL.'Hincks, Brit. Zooph. 105. 



DICOTYLEDONS. One of the two 

 great divisions of the Angiospermous Flow- 

 ering Plants, synonymous with the Exogens 

 of Decandolie, and opposed to Monocotyle- 

 dons, the name being derived from the 

 condition of the embryo prevailing through- 

 out the vast majority of plants included in 

 this assemblage. As in all other natural 

 groups, instances occur wherein the parti- 

 cular character from, which the name is 

 derived, the presence of a pair of cotyledons 

 in the embryo, is absent, as in Orobanche, 

 &c. (like the Orchidaceae and other plants 

 among the Monocotyledons) ; but in these 

 cases the plants agree generally with Dico- 

 tyledons in all the rest of the prominent 

 characters, such as the structure of stem, 

 leaves, plan of flower, &c. See VEGETABLE 

 KINGDOM, WOOD, and SEED. 



DICRANA'CE^. A family of Apocar- 

 pous operculate Mosses, branching by in- 

 novations, or with the tops of the fertile 

 branches several times divided. Leaves 

 lanceolate or subulate, channelled-concave, 

 with a nerve mostly dilated and flattened, 

 rarely slender, scarcely cylindrical. The 

 cells prosenchymatous (often mingled with 

 parenchymatous), rarely papillose, mostly 

 empty, often thickened upwards, thereby 

 rounded or elliptical ; the basilar cells ar- 

 ranged in a curved manner at the margins 

 of the leaves, distinctly diverse, paren- 

 chymatous, lax, thick, large, flat or with a 

 more or less thick and patel lif orm front, de- 

 licate or robust, hyaline, fuscous, brown or 

 purple, ultimately marcescent, mostly very 

 conspicuous (alar cells). Capsule oval or 

 cylindrical, arched or straight, with a su- 

 bulate operculum. Peristome, if present, 

 purple, teeth trabeculate. 



British Genera. 



Blindia. Calyptra dimidiate, hood-sha- 

 ped, peristome wanting or simple, then 

 of sixteen equidistant, lanceolate, distantly 

 articulated, smooth, slender teeth, slightly 

 trabeculate within, purple, cartilaginous. 

 Capsule exannulate. 



Dicranum. Calyptra dimidiate. Peri- 

 stome simple, teeth connate at the base into 

 a more or less emergent membrane, or equi- 

 distant and arising below the orifice of the 

 capsule, split more or less deeply, even in 

 some cases to the base, into two or rarely 

 more free arms, purple below, trabeculate- 

 nodose above (figs. 169 & 170). 



Fig. 169. 



Fig. 170. 



Fig. 171. 



Dicranum palustre. 



Fig. 169. Mouth of the capsule with the peristome 

 everted. Magnified 40 diameters. 



Fig. 170. Portion of the peristome. Magnified 100 

 diameters. 



DI'CRANUM, Hedw. A genus of Di- 

 cranacese (Apocarpous operculate Mosses), 

 including numerous British spscies, very 

 varied in size and habit ; some, such as D. 

 scoparium, very common (see ANGSTRCEMIA 

 and LEUCOBRYUM). 



BIBL. Wilson, Bn/ol. Brit. p. 61. 



DICTYD'IUM, Schrad. 

 A genus of Myxomycetes; 

 exceedingly elegant little 

 plants, growing upon rotten 

 wood. The peridium is ex- 

 cessively delicate, and the 

 peculiar capillitium adherent 

 to it ; so that, when the 

 spores are expelled, the trans- 

 parent case appears like a 

 cage, formed of the veins 

 alone. There are no fila- 

 ments mingled with the 

 spores. D. umbilicatum(tig. 

 171) is a British species ; it 

 is of a brownish-purple co- 

 lour until the spores are dis- umb ._ 



charged, then hyaline ; it is licatum. 

 gregarious in its habit of Magn. 25 diam. 

 growth. 



BIBL. Berk. Hook. Br. Fl. v. pt. 2. 317; 

 Greville, Sc. Crypt. Fl. pi. 153 ; Fries, Syst. 

 Myc. iii. 164; Schrad. Nov. Gen. 11; 

 Corda, Ic. Fung. v. pi. 3. fig. 36. 



BICTY'OCHA, Ehr. The nature of the 

 curious bodies, of which the genus Die- 

 tyocha consists, is unknown. They consist 



