DEN DYS.] 



PLANTS. 



117 



of which were attached leaves, prob- 

 ably ^cylindrical. Type D. euphorbio- 

 ides. 



striata, Lesquereux, 1880, Coal Flora of 



Pa., p. 431, Coal Meas. 

 DBNDROPHYCUS, Lesquereux, 1884, Coal 

 Flora of Pa., vol. 3, p. 699. [Ely. den- 

 dron, tree; phukos, sea-weed.] Eoot 

 composed of tubulose flattened fila- 

 ments, irregularly branching and widely 

 spreading from the base of the rhizoma ; 

 rhizoma cylindrical, simple, long and 

 thick; fronds at first top-shaped, very 

 large, tree-like, and many times divided 

 when opened ; primary and secondary 

 branches thick and somewhat flat on 

 one side, dichotomous; ultimate divi- 

 sions cylindrical, narrow and pointed. 

 Type D. desori. 



desori, Lesquereux 1884, Coal Flora of 

 Pa., vol. 3., p. 699, Devonian. 



DESMIOPHYLLUM, Lesquereux, 1880, Coal 

 Flora of Pa., p. 556. [Ety. desmos, 

 band; phyllon, leaf.] Stems slender; 

 leaves narrow, sublinear, gradually en- 

 larged from the base, single and sparse 

 or joined 3 or 4 together and fascicu- 

 late at the base ; surface of stem and 

 leaves irregularly ribbed lengthwise by 

 prominent large bundles of nerves 

 buried under the epidermis, which is 

 thick, irregularly granulose, by split- 

 ting of the coaly layer. Type D. 

 gracile. 



gracile, Lesquereux, 1880, Coal Flora of 



Pa., p. 557, Coal Meas. 

 DICRANOPHYLLUM, Grand 'Eury, 1877, Flore 

 Carbonifere, pi. 30. [Ety. dikranos, two- 

 pointed ; phyllon, leaf.] Stems slender, 

 leaves narrow, linear, subcoriaceous, of 

 various length, forking, or dividing in 

 filaments in the upper part, marked 

 with a few thick primary nerves, and 

 intermediate nervilles, more or less im- 

 mersed into the epidermis. 



dichotomum, Lesquereux, 1880, Coal Flora 

 of Pa., p. 553, Coal Meas. 



dimorphum, Lesquereux, 1878, Proc. 

 Am. Phil. Soc., p. 329, and Coal Flora of 

 Pa., p. 554, Coal Meas. 



Dictuolites, see Dictyophyton in the class 

 Protozoa. 



becki see Dictyophyton becki. 

 DICTYOPTERIS, Gutbier, 1835, Verst. Zwick. 

 Schwarzk, p. 63. [Ety. dictyon, net; 

 pteris, fern.] Frond bipinnate; pin- 

 nules cordate, truncate or rounded 

 at the base, sessile or short pedicelled, 

 oblong, obtuse or lanceolate, entire; 

 veins flexuous, connected by flexures 

 and intersections, forming a more or 

 less distinct and close reticulation 

 of polygonal meshes. Type D. brong- 

 niarti. 



cordata, Roemer, in Pflanzen d. prod. 

 Steinkohlengeb. am Harz und Piesberg 

 in Palseontographica, vol. 9, p. 186, 



and Coal Flora of Pa., p. 833, Coal 

 Meas. 



neuropteroidea, Gutbier, 1852, Verst. 

 Stein Sachs., p. 23, and Coal Flora of 

 Pa., p. 833, Coal Meas. 

 obliqua, Bunbury, 1847, Quar. Jour. Geo. 

 Soc., vol. 3, p. 427, and Coal Flora of 

 Pa., p. 146, Coal 

 Meas. 



rubella, L e s q u e - 

 reux, 1870, Geo. 

 Sur. 111., vol. 4, 

 p. 388, Coal Meas. 

 scheuchziri, H o f f - 

 man, in Roem. 

 Pflanz. d. Koh- 

 lengeb. am Harz 

 in Paleont. IX, p. FlQ - S2.-plctyopterls 

 186, and Coal obliqua " 



Flora of Pa., p. 832, Coal Meas. 

 DIDYMOPHYLLUM, Gceppert, 1841, Gatt. der 

 Foss. Pflanzen, p. 35. [Ety. didymos, 

 double ; phyllon, a leaf.] Trunk arbores- 

 cent, cylindrical ; leaves double, united 

 at the base, disposed in spiral order, 

 appressed ; areoles prominent, reni- 

 forin, each resembling a pair of small 

 areoles attached to each other. Type 

 D. schottini. 



oweni, Lesquereux, 1870, (Sigillaria 

 oweni,) Geo. Sur. 111., vol. 4, p. 498, 

 Coal Meas. 

 reniforme, Dawson, 1862, Quar. Jour. Geo. 



Soc., vol. 18, p. 309, Ham. Gr. 

 Diplazites emarginatus, see Pecopteris emar- 



ginata. 



DIPLOSTEGIUM, Corda, 1845, Beitrage zur 

 Flora der Vorwelt, p. 112. [Ety. diplos, 

 double ; stege, a covering ; but spelled 

 by Corda Diplotegium.] Thick trunks 

 of trees longitudinally furrowed ; bark 

 thick, and imbricated in short cylin- 

 drical overlaps. Type D. brownanum. 

 brownanum, Corda, 1845, 

 Beitrage zur Flora der 

 Vorwelt, p. 112, Coal 

 Meas. 



retusum, Dawson, 1863, 

 Can. Nat., vol. 8, and 

 Acad. Geol., p. 490, Coal 

 Meas. 



truncatum, Lesquereux, 

 1860, Geo. Sur. Ark., vol. 2. Syn. for 

 Knorria imbricata. 



DISCOPHYCUS, Walcott, 1879, Trans. Alb. 

 Inst., vol. 10, p. 19. [Ety. diskos, disk ; 

 phukos, sea-plant.] Frond discoid, 

 slightly convex, and substance coria 

 ceous. Type D. typicale. 

 typicale, Walcott, 1879, Trans. Alb. Inst., 



vol. 10, p. 19, Utica slate. 

 DYSTACTOPHYCUS, Miller & Dyer, 1878, Cont. 

 to Pal., No. 2, p. 2. [Ety. dustaktos, hard 

 to arrange ; phukos, sea-plant.] Frond 

 mammiform, expanded and concen- 

 trically wrinkled. Type D. mammilla- 

 num. 



FIG. 83. 



Diplostegium 



retusum. 



