[150] I subjoin a definition of the genera Pinus and Abies, for the use of the student.
Pinus.—Fruit-catkins ovate, roundish, or cylindrical closely set with thick two-flowered scales; forming an imbricated cone, composed of numerous ligneous angular, or flat, rigid scales, having attached to the inside of each two seeds crowned with a thin membraneous, falcate, oblong, or roundish wing; the scales are composed of a thick woody substance, forming an angular surface, with a recurved point. The Pines are evergreen trees, with from two to five narrow, angular leaves springing from each sheath. Cotyledons four to twelve.
Abies.—Cones with thin flat scales, which are more membranous at the extremities than in Pines: the leaves are emarginate, short solitary, needle-shaped, angular or flat.
WALCHIA.
Walchia. [Lign. 60.]—The fossil coniferæ thus named by Sternberg, have numerous closely set, regularly pinnated branches, resembling those of Araucaria excelsa, and which are thickly beset with foliage. The leaves are sessile, compact, enlarged at the base, tetragonal or falciform, and slightly decurrent; they often vary considerably in form and length on the same bough. The branches are in some examples terminated by oblong cones, composed of imbricated, oval or lanceolate, pointed scales, the summits of which are not recurved, as in the Araucariæ. The trees of this genus are closely related to the Araucaria excelsa, and A. Cunninghami. Some species occur in the Coal formation at St. Etienne and Autun;[151] others (as Walchia hypnoides) in the schists of Lodève, and in the copper slates of the Zechstein in Mansfeld.[152]
[151] "Mines de Houille de Vettin, &c." See "Tableau des Vég. Foss." p. 70, par M. Brongniart.
[152] Missing!
Lign. 60. Walchia hypnoides; 1/3 nat.
Permian, Lodève.
Part of a bough with six of the branches bearing terminal cones.