The long linear leaves of some species of Podocarpus, in which the lamina is traversed by a single vein, recall the pinnae of Cycas; the branches of some Dacrydiums and other forms closely resemble those of lycopods; these superficial resemblances, both between different genera of conifers and between conifers and other plants, coupled with the usual occurrence of fossil coniferous twigs without cones attached to them, render the determination of extinct types a very unsatisfactory and frequently an impossible task.
The molten sulphur accumulates on the sole, whence it is from time to time run out into a square stone receptacle, from which it is ladled into damp poplar-wood moulds and so brought into the shape of truncated cones weighing 110 to 130 lb each.
Williamson thoroughly worked out, in petrified specimens, the organization of a cone which he named Bowmanites Dawsoni; it was subsequently demonstrated by Zeiller that this fructification belonged to a Sphenophyllum, the cones of the well known species S.
The leaves, short and glaucous, like those of the Scotch fir, have deciduous sheaths; the cones have recurved scale-points like those of the cheer pine.
The foliage much resembles that of the Scotch fir, but is shorter, denser and more rigid; the cones are smaller but similar in form.
C. atlantica, the Atlas cedar, has shorter and denser leaves than C. Libani; the leaves are glaucous, sometimes of a silvery whiteness, and the cones smaller than in the other two forms; its wood also is hard, and more rapid in growth than is that of the ordinary cedar.
There are few craters on the loftier heights, but on the coasts there are several groups of small cones with craters, some of lava, others of tuf a.
It bears cones as large as a man's head.
The cones of cycads attain in some cases (e.g.
The larch is raised from seed in immense numbers in British nurseries; that obtained from Germany is preferred, being more perfectly ripened than the cones of home growth usually are.