WOOD, 



[ 822 ] 



WOODWARDIA. 



wheel; wood in the state of coal in like 

 manner (see PREPARATION, FOSSIL WOOD, 

 and COAL). 



Gymnosperms. In this division of the 

 Flowering Plants we also meet with two 

 types of structure : 



Coniferce. Here the character of the 

 wood agrees in general with that of the 

 typical Dicotyledons, with certain distinc- 

 tions ; namely, although the medullary 

 sheath of spiral vessels exists, no ducts or 

 vessels occur in the mass of wood external 

 to this, which is wholly composed of pros- 

 enchymatous cells, with "bordered pits, in 

 single (Plate 48. fig. 4) (usually), double, or 

 treble (Araucaria) rows (fig. 6) ; in Taxus 

 accompanied in part by a spiral-fibrous band 

 (fig. 4). The particulars of these forms are 

 given under CONIFERS. It may be men- 

 tioned that the " woody parenchyma " of 

 Dicotyledons seems to be represented here 

 by the cords of parenchymatous cells in 

 some cases traversing the prosenchyma, ulti- 

 mately filled with resinous deposits (" cords 

 of secretion-cells"). 



Cycadacece. The earliest condition of 

 the stems here appears to resemble that in 

 Coniferse ; but no annular rings are formed. 

 Concentric layers are produced at intervals, 

 however, separated by parenchymatous 

 layers. The true mode of origin of these 

 does not appear to be clearly made out. 

 The wood is composed of pitted prosenchy- 

 matous cells (PI. 48. fig. 20), without ves- 

 sels or ducts, excepting in the medullary 

 sheath of spiral vessels. 



Some elaborate and interesting researches 

 on the peculiar intimate structure of wood 

 and tissues have been published by Har- 

 ting, Sanio, Na'geli, and Hanstein ; but we 

 have no space to analyze these long papers 

 here. 



For further details on the markings of 

 the ducts, &c., see PITTED and SPIRAL 



STRUCTURES. 



BIBL. Lindley, Intr. to Sot. ; DeCandolle, 

 Organographie, i. 161 ; Meyen, Pflanzen- 

 phys. i. 331; Goeppert, Struct. Conifer. 

 1841, Linntea, xvi., xvii., Ann. So. Nat. 2. 

 xviii. 1 & 317 ; Brongn. Veget. Fossiles, 1828, 

 et seq., Ann. So. N. 1. xvi. 589; Hooker, 

 Flor. Antarct., Ann. So. Nat. 3. v. 193; 

 Gaudichaud, Recherches Anat., and Ann. 

 Sc. Nat. 3. passim; Meneghini, Ricerche 

 sulla Slruttura Monoc. ; Schacht, Pftanzen- 

 zelle, 193, Das Baum, 94 ; Criiger, Sot. Zeit. 

 viii. 99, x. 465 ; Tr<cul, Ann. Sc. Nat. 3. 

 xviii., xix. ; xx., 4. i., ii., Hi. j Milde, Seitr. z. 



Sot. 1850 ; Hanstein, Pringsheim's Janrb. i. 

 232; Sanio, Linncea, 1858; Hartig, Sot. 

 Zeitung, xvii. ; Henfrey-Masters, Sot. ; 

 Sachs, Sot. ; Kny, HolsJcorper, 1882. 



WOOD'SIA, Brown. A genus of Dick- 

 soniese (Polypodiaceous Ferns), represented 

 by two rare indigenous species, W. llvensis 

 and hyperborea. Sori globose ; indusium 

 inferior, cup-shaped or globose, sometimes 

 enclosing the sorus, opening at the top, the 

 mouth or margin irregular, iobed or fringed 

 with long hairs (fig. 809). Several tropical 

 species. (Hooker, Syn. 46.) 

 Fig. 809. 



Woodsia hyperborea. 



A sorus and indusium with a hair-like fringe. 

 Magnified 50 diameters. 



WOODWAR'DIA, Smith. A genus of 

 Blechnese (Polypodiaceous Ferns). Several 

 species; exotic. 



Fig. 810. 



Woodwardia. 

 A fertile pinnule. Magnified 5 diameters. 



