PRO. PSE.] 



PLANTS. 



135 



Blechnum, a genus.] Fronds large, pin- 

 nate ; rachis thick, scaly toward the base ; 

 pinnae long, narrow linear-lanceolate, 

 acuminate, entire, enlarged at base on 

 the lower side to a decurring auricle, 

 generally free ; medial nerve percurrent ; 

 lateral veins open, curving to the bor- 

 ders, forking twice. Type P. holdeni. 

 holdeni, Andrews, 1875, (Alethopteris 

 holdeni,) Ohio Pal., vol. 2, 420, Coal 

 Meas. 



PROTOSTIGMA, Lesquereux, 1877, Proc. Am. 

 Phil. Soc., p. 169. [Ety. protos, first; 

 stigma, a brand or dot.] Stems with 

 rhomboidal scars as in Sigillaria, but 

 without vascular scars in the middle. 

 Not a land-plant, but a f ucoid. Type P. 

 sigillarioides. 



sigillarioides, Lesquereux, 1877, Proc. Am. 

 Phil. Soc., p. 169, Hud. Riv. Gr. 



PROTOTAXITES Dawson, 1859, Quar. Jour.. 

 Geo. Soc., vol. 15, p. 484. [Ety. protos, 

 first ; taxus, yew-tree ; so named from 

 the spirally marked cells character- 

 istic of the genus Taxites.'] Woody and 

 branching trunks, with concentric rings 

 of growth and medullary rays ; cells of 

 pleurenchyma not in regular lines, 

 cylindrical, thick-walled, with a double 

 series of spiral fibers ; discs or bordered 

 pores few, circular and indistinct. The 

 specimens found are usually silicified, 

 with the bark in a coaly state. Type 

 P. logani. 



logani, Dawson, 1859, Quar. Jour. Geo. 

 Soc., vol. 15, p. 484, Devonian. This is 

 the oldest known exogenous tree in 

 America, according to Dawson, but 

 Carruthers says it is a huge sea-weed 

 and has named it Nematophycus logani. 



PSARONIUS, Cotta, 1832, Dendrol in Be- 

 ziehung, p. 27. [Ety. psaros, speckled.] 

 Stems of tree-ferns, covered below by 

 adventive roots, increasing by their 

 superposition the conical base of the 

 trunks ; cortex thick, parenchymatous ; 

 woody cylinder, subdivided into 

 branches composed of fascicles of ves- 

 sels either half cylindrical or diversely 

 plicate, immersed in cellular medullar 

 tissue. Type P. helmintholithus. 

 erianus, Dawson, 1871, Foss. Plants Can., 



p. 58, Ham. Gr. 



textilis, Dawson, 1871, Foss. Plants Can., 

 p. 59, Ham. Gr. 



PSEUDOPECOPTERIS, Lesquereux, 1880, Coal 

 Flora of Pa., p. 189. [Ety. pseudo, 

 false ; Pecppteris, a genus.] Primary 

 rachis forking near the base in diverg- 

 ing branches of equal size, or divari- 

 cate and dichotomous ; branches poly- 

 pinnate, ultimate divisions sometimes 

 forked ; pinnules connate or separated to 

 the base, of various shape, oblong-ob- 

 tuse or ovate-lanceolate, oblique or in 

 right angle, decurring to the rachis and 

 bordering it by a narrow wing ; lateral 

 veins oblique, generally for king once, the 

 lowest pair twice. Type P. mazonana. 



abbreviata, Lesquereux, 1854, (Sphenop- 



teris abbreviata,) Bost. Jour. Soc. Nat. 



Hist., vol. 6, p. 419, and Geo. Sur. Pa., 



vol. 2, p. 861, Coal Meas. 

 acuta, Brongniart, 1828, (Sphenopteris 



acuta,) Hist. d. Veg. Foss., p. 207, and 



Coal Flora of Pa., p. 215, Coal Meas. 

 anceps, Lesquereux, 1880, Goal Flora of 



Pa., p. 207, Coal Meas. 

 andrseana, Roehl, 1868, (Sphenopteris an- 



drseana,) Fossile Flora der Steinkohlen 



formation Westphalens, p. 62, and Coal 



Flora of Pa., p. 754, Coal Meas. 

 callosa, Lesquereux, 1866, (Pecopteris 



callosa,) Geo. Sur. 111., vol. 2, p. 442, 



Low. Coal Meas. 

 cordato-ovata. Weiss, 1869, (Neuropteris 



cordato-ovata,) Foss. Flor. d. jungst. 



Steink. form., p. 28, and Coal Flora of 



Pa., p. 205, Coal Meas. 

 decipiens, Lesquereux, 1854, (Sphenop- 



teris decipiens,) Bost. Jour. Soc. Nat. 



Hist., vol. 6, p. 420, and Geo. Sur. Pa., 



vol. 2, p. 862, Coal Meas. 

 decurrens, Lesquereux, 1854, (Pecopteris 



decurrens,) Bost. Jour. Soc. Nat. Hist., 



vol. 6, p. 424, and Geo. Sur. Pa., vol. 2, 



p. 867, Coal Meas. 

 denudata, Lesquereux, 1880, Coal Flora 



of Pa., p. 212, Coal Meas. 

 dimorpha, Lesquereux, 1880, Coal Flora 



of Pa., p. 201, Coal Meas. 

 glandulosa, Lesquereux, 1854, (Sphenop- 



teris glandulosa,) Bost. Jour. Soc. Nat. 



Hist., vol. 6, p. 420, and Geo. Sur. Pa., 



vol. 2, p. 862, Coal Meas. 

 hispida, Lesquereux, 1884, Coal Flora of 



Pa., p. 755, Coal Meas. 

 hymenophylloides, Lesquereux, 1870, 



(Alethopteris hymenophylloides,) Geo. 



Sur. 111., vol. 4, p. 393, Coal Meas. 

 irregularis, Sternberg, 1833, (Sphenop- 



teris irregularis,) Vers. 



Geog. Darst. Flor. d.Vorw., 



vol. 2, p. 68, Coal Meas. 

 latifolia, Brongniart, 1828, 



(Sphenopteris latifolia,) 



Hist. d. Veg. Foss., p. 205, 



and Coal Flora of Pa., p. 



215, Coal Meas. 

 macilenta, Lindley & Hut- 



ton, 1835, Foss. Flora, vol. I 



2, pi. 151, and Coal Flora 



of Pa., p. 219, Coal Meas. 

 mazonana, Lesquereux, 



1870, (Alethopteris maz- 



onana,) Geo. Sur. 111., vol. 



4, p. 391, Low. Coal Meas. 

 muricata, Brongniart, 1828, 



(Pecopteris 



muricata,) 

 ., p. 352, 



Hist. d. Veg. 



and Coal Flora of Pa., p. 



203, Coal Meas. FlQ 66> 



nervosa, Brongniart, 1828, Pseudopecop- 

 ( Pecopteris nervosa,) Hist, terismazo- 

 d. Veg. Foss., p. 297, and nana> 

 Coal Flora of Pa., p. 197, Coal Meas. 



newberryi, Lesquereux, 1854, (Sphenop- 

 teris newberryi,) Bost. Jour. Soc. Nat. 



