A SYNOPSIS OF THE AMERICAN FIRS. 343 
On the differences of the leaf-structure we can base the subdivisions of the genus with much 
greater certainty than on the length of the bracts, as was formerly done. 
BatsaME& : Resin-ducts within the parenchyma, in the interior of the leaf ; leaves on lower branches 
Sec. 
notched, and mostly without stomata on the upper side, on fertile branches entire, obtuse, or often acute, mostly with 
a few or more stomata above, towards the tip. — Two eastern and one northwestern species. 
* Exserta: bracts protruding, recurved. 
1. A. Fraser. 
* * Incluse: bracts shorter than the scales. [596 (4)] 
2. A. balsamea. 3. A. subalpina. 
Sec. II. Granpes: Resin-ducts close to the epidermis of the lower side, toward the edges ; leaves on lower 
branches notched or obtuse ; on upper, obtuse, rarely ever acute ; bracts enclosed. — Two western species. 
4. A. grandis, 5. .A. concolor. 
Sec. III. Bracrzata#: Resin-ducts as in last; upper side of the rigid, mostly acute leaves without stomata, with 
a continuous layer of hypoderm cells, usually similar cells within the sheath of the fibro-vascular bundle ; pallisade- 
parenchyma very strongly developed ; bracts exsert. — A Mexican and a southwestern species. 
A, religiosa. 7. A. bracteata. 
Sec. [V. Nopixes : Leaves of the adult tree and especially of the fertile branches quadrangular, short, curved, 
but scarcely twisted ; serene close to the epidermis of the lower side, and equidistant from the edge and keel ; 
fibro-vascular bundles single ; stomata on both sides ; leaves of young trees much like those of Sec. 11. — Two species 
of the higher mountains of the Pacific slope. 
* Exserta: bracts protruding. 
8. A. nobilis. 
« * Inclusa: bracts shorter than scales, 
9. A. magnifica, 
1, A. Frasert (Pinus, Pursh. Fl. 2, 639, 1816; Parlatore in DC. Prod. 16, 2, 419), Lindl. Pen. Cyc. 1, No. 5 
(1833), Forbes, Link, ete. This is probably the most local species in the United States, being confined to the tops of 
the highest mountains of North Carolina, which have an altitude of 6,000 feet or more, and the tops of which it covers 
together with some Picea nigra, but it never occurs mixed with the following species. — A small tree rarely as much as 
30 or 40 feet high, and 12 or 18 inches in diameter, probably never more than 60 to 75 years old, with cinnamon-brown 
smoothish bark ; readily distinguished from balsamea by the shorter, more oval cones with largely exsert and reflexed 
bracts, and always, even when sterile, by the almost uninterrupted stratum of hypodermic cells on the upper side of the 
leaf, more crowded on the edges. The white bands on the under side of the leaf consist usually of 8 or 10, or even 12 
series of stomata; height of scales (without the stipe) equal to one-half or two-thirds their width; length of seeds 
equal to length a © idth of wing. — Forms of the next de Steen with exsert tips of bracts, in the mountains of Pennsyl- 
vania, Sansa. and other northern regions, seem to have been mistaken for this species. In eastern as well as in 
Enropean gardens forms of balsamea are often cultivated under the name of Fraseri. 
2. A. BALSAMEA (Pinus, L. Sp. Pl. 1421, 1753; Parl. 1. c. 423), Marshall Arb. Am. 102, ape bed [597 (5)] 
A, balsamifera, Michx. FI. 2, 207, in part. — The northeastern “ Balsam ” extends from Canada and the n 
eastern States along the mountains to Virginia, and along the Great Lakes to and beyond the wana It isa 
larger tree than the last, often 70 feet high, 14 feet in diameter, and up to 150 years old ; bark smooth, and reddish- 
en young, brown and much cracked in old trees. Its slenderer cones with enclosed bracts (only their points 
sometimes protruding), and especially the leaves with scarcely any hypoderm cells above and very few on edges and 
keel (fewer than in any other of our species and sometimes none) and with narrower bands of stomata below (of 4-8, 
usually about 6 series), readily distinguishes it. A. Hudsonia of the gardens, often considered as a form of Fraseri, is 
a sterile dwarf form of balsamea, found also on the White Mountains of New Hampshire above the timber line. 
* 3, A. suBALPINA, Engelm. in Am. Naturalist, 1876, p. 555. A. lasiocarpa, Hook. Fl. B. A. 2, 163.2 A. bifolia, 
Murr. Proc. R. Hort. Soc. 3, 318. A. amabilis, Parl. 1. c. 426, in part. — Closely allied to the last species, the western 
representative of which it must be considered to be ; it extends from the higher mountains of Colorado and the adjoin- 
ing parts of Utah northward to Wyoming and Montana, where it is the only species, and westward to the mountains 
of Oregon and into British Columbia (Fraser’s River) and southward probably to Mount Shasta, always scattered in 
* This description is reprinted in the Gardeners’ Chronicle for Feb. 19, 1881, p. 236, where figures from photographs 
sent by Dr. Engelmann are published. — Eps. 
