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could not have, though in almost every case he confirms the conclusions at which we had already arrived.

About thirty species are known, of which twenty-six have been introduced and are distinguished below. The silver firs are natives of the temperate parts of the northern hemisphere, usually occurring in mountainous regions; attaining high elevations towards the south, as in Guatemala, Algeria, Himalayas, and Formosa ; and descending to low levels in the extreme north, as Alaska, Labrador, and Siberia.

The following table is based upon characters taken from the foliage, buds, and shoots of lateral branches, occurring on the lower part of the tree. As regards the leaves, their arrangement upon the branchlets, the position of the resin-canals, and whether the apex is entire or bifid must be noted. The presence of stomata on the upper surface of the leaf is peculiar to certain species. The young shoots are either smooth or deeply grooved with prominent pulvini; and are glabrous in some species, pubescent in others, the pubescence when present being either confined to the grooves or spread over the whole branchlet. The buds vary in size and shape and also in the quantity of resin, which in some cases is so slight that they may be described as non-resinous; whilst in other species the scales are covered with or deeply immersed in resin.

Certain species are distinguishable at a glance by some prominent character. A. bracteata has a bud entirely different from that of any other species. 4. Pinsapo, with its short, thick, rigid leaves, standing out radially from the shoot, is unmis- takable. 4. cephalonica, with a more imperfect radial arrangement, is distinguished by its long flattened leaves ending ina single sharp cartilaginous point. 4. firma is peculiar in its remarkably broad very coriaceous leaves, which end in two sharp unequal points. A. grandis has the leaves quite pectinate in the horizontal plane, those of the upper rank about half the size of those below. 4. Martesz is dis- tinguished by the shoot being densely covered with a ferruginous tomentum. A. brachyphylla and A. Webdtana have deeply-furrowed shoots with prominent pulvini, which become more marked in the second year; and the bark begins to scale very early on the branches and trunk of the tree. A. modtlis and A. magnifica are peculiar in the upper median leaves curving up from the shoot after being appressed to it for some distance. A. Pindrow has long pale green leaves very irregularly arranged.

I. Leaves radially arranged on the branchlets; apex of the leaf not bifid.

1. Abies Pinsapo, Boissier. Spain. See p. 732.

Leaves rigid, short, less than 2 inch long, thick, acute at the apex ; resin-canals median. Shoots glabrous. Buds resinous.

2. Abies cephalonica, Loudon. Greece. See p. 739.

Leaves thin, flattened, about 1 inch long, ending in a sharp cartilaginous point ; resin-canals marginal. Shoots glabrous. Buds resinous.

In var. Afpollinis, the radial arrangement is imperfect, and the leaves end in a short point.