370 REVISION OF THE GENUS PINUS. 
NOTES. 
1. P. Peuce, Griseb., may after all be distinct from P. excelsa ; it has much shorter leaves and sheaths, and, if my 
specimen can be relied on, a short fruiting peduncle; the structure of the leaf is nearly the same in both. P. Peuce, 
excelsa, and monticola have a layer of strengthening cells all around under the epidermis, interrupted only by the 
stomata, and not in distinct bundles as in Lambertiana and Bonapartea, while P. Strobus, Ayacahuite, and parviflora 
have scarcely any. They all have regularly two dorsal ducts only. In P. excelsa I have repeatedly found a third, 
ee ce ae a parenchymatous one. 
rviflora, Sieb. & Zucc, A branch in Herb. Haenke in the Prague Museum, marked “ P. heterophylla, Presl, 
oe sey ” seems to belong to this species, which is distinguished by slender, distantly and very slightly serrulate 
leaves, and scarcely any strengthening cells. 
3. P. Bonapartea, Roezl. Prof. E. Purkinje, of the Foresters’ Academy of Weiswasser, Bohemia, who was prob- 
ably the first to carefully study the microscopic anatomy of the pine-leaves with a view to the diagnosis of the species, 
and who is now publishing the results of his investigations in an extensive and copiously illustrated work, has directed 
my attention to the leaf-structure of this form. It deviates from all the other Strobi in having numerous, usually 7 
ducts, 3 on the back and 2 on each of the upper sides, and having strengthening cells in numerous bundles all around 
and especially in the angles. I find no stomata on the back. Roezl’s P. Don Pedri has exactly the same structure, but 
has 3 or 4 series of stomata on the back ; both evidently belong together. Though I have not been able to study the 
flowers and fruit, I do not hesitate to pronounce it distinct from P. Ayacahuite, which, like P. Strobus, has scarcely 
any strengthening cells, and only 2 dorsal ducts. 
4 Cembra, Linn. The ducts, generally in the middle of the parenchyma, sometimes nearly approach the epi- 
dermis, but I have always found them separated from it by at least one layer of parenchymatous cells, 
hylla, Torr. & Frem. The number of ducts is excessively variable; I have found from 3 to 14 in 
different leaves. The leaves are usually curved, and the upper side, proved to be such by the relative position of the 
wood and bast cells (see p. 165), is always directed toward the branch, Sometimes two-leaved bundles occur. It is 
an open question whether the four species of the subsection Cembroides may not properly be united into one, as the 
difference of flowers and fruit is very slight, and that of the foliage only relative. 
6. P. Balfouriana, Jeffrey, and P. aristata, Engelm., of the Colorado Rocky Mountains, are identical in [179] 
leaf-structure and in flowers, and must be united, though the cone of the former is elongated, often even cylindri- 
cal, the apophyses thicker and peculiarly spongy, and at maturity unarmed, while the other has an oval cone with 
thinner scales and awnlike prickles. In Utah and Nevada a form occurs with cones like the latter, but with short, 
stout, recurved goer Parlatore enumerates aristata, but does not mention Balfouriana. 
asia, Royle, and its two allies, form a very asiaoeon little group. Leaves in this species with 2 dorsal 
ducts ; Soha ae cells very slight and only in the corners; male flowers 1 inch long, slender ; involucral bracts 
12 to 14, exterior half as long as the inner ones, all Sealey pointed ; anthers ? to 1 line long; crest only 3 line 
wide, nearly entire. 
P. insularis, Endl, has similar leaves, ducts often indistinct, strengthening cells slight in the corners and some 
scattered under the epidermis and also near the vessels ; male flowers 1 inch long ; involucral bracts about 8, outer 
pair ae than half as long as the inner ones ; anthers less than 1 line long, crest nearly entire. 
P. longifolia, Roxb. Ducts few (in Wallich’s specimens), or many (in Hooker and Thompson’s), or none at all 
(Hooker's ; Thuret’s cult.) ; strengthening cells strongly developed in bundles all around leaf ; bracts large, strongly 
fringed, deciduous; male flowers larger than in last, 1-1} inches long, thicker ; anthers 1} lines long ; crest ? line 
wide, strongly fringe-denticulate ; involucre not seen. The thick bundles of strengthening cells and the larger male 
flowers readily distinguish it from the two others. 
8. P. montana, Duroi, is so well characterized that it is inconceivable how it could have been taken for a variety 
of P. sylvestris, unless some hybrid forms, which are said to occur, have created the difficulty. The involucral bracts 
are always more numerous, usually about 6, the anthers crested, the female aments subsessile, and the young cone 
erect ; in sylvestris the involucral bracts rarely exceed 3, the crest of the anthers is reduced to a small ridge or a few 
teeth, the female ament is not longer than its peduncle and becomes recurved soon after flowering. 
9. P. resinosa, Ait., is the only American representative of this well characterized group. The 6 involucral 
scales are articulated in the middle, the upper part falling off early (p. 168) ; ducts almost always only 2 on the upper 
side of the leaf. 
10. P. densiflora, Sieb. & Zuce. Leaves with numerous ducts, mostly surrounded by strengthening cells, also 
some of these within the sheath ; in a few instances, in Japanese as well as in cultivated specimens, the strengthening 
cells are almost wanting ; ale flowers oval, only 2 to 3 lines long, in an elongated spike ; involucrum of 3 or 4 or 
