PINETUM BRITANNICUM 
2 
can scarcely be called lacerated, but only slightly waved or unequal; pollen yellow. The male catkins mall 
the trees here spoken of, and especially in the Corsican Laricio, come to perfection remarkably late as com¬ 
pared with other European Conifers. The catkins of the Corsican or Calabrian Laricio generally shed their 
pollen only at the end of May or beginning of June. The Laricio Pyrenaica is a week or ten days earlier, 
and nigricans alias austriaca and Pallasiana fully two weeks earlier. Cones (see plate) sometimes solitary, 
at others in twos or threes, sessile, growing on last year’s shoots, varying in size from 2 to 3 inches in length, 
and a little more than one inch in diameter, convex on the one side, and straight or slightly bent in on the 
other; their colour when young is green, when mature tawny, and purple on that part of the scale which is 
not exposed to the light until the cone opens (fig. 6); their scales (figs. 7, 8, and 9) have their apophysis 
raised and shining, slightly thickened, with the outline of the upper margin round, keeled transversely, the 
keel often bisinuate, sharp, and terminating in a central mucro, which has a very small prickle often rubbed 
off. Seeds greyish or black, twice as large as those of the Scotch Fir, the wing long (see plate), slender, 
straight on the back, and gently rounded on the other margin. Germinal leaves six to eight in number. 
The leaf-structure of P. Laricio as seen in cross sections is as follows : first, the epidermis, next a 
double layer of hypoderm-cells, surrounding the central cellular tissue of the leaf This latter is traversed 
in the centre by a double fibro-vascular bundle surrounded by a “ bundle-sheath.” Between the central 
bundle and the marginal hypoderm are a variable number of resin canals, each one surrounded by “ strength¬ 
ening cells.” We have ascertained that the same structure occurs in the forms grown at Kew (1883) under 
the names of austriaca , Fenzlii , Caramanica, Pallasiana, pygmcea, neglecta , and Heldreichii, so that the leaf- 
structure affords no help in this case in the discrimination of allied forms. 
It is a question of difficulty whether Pinus Laricio, P. Laricio var. Pyrenaica, P. austriaca, P. Cala- 
brica, and P. Pallasiana should not all be treated as mere climatal varieties of one species. That they are 
all of the same type cannot be disputed, and there can be as little doubt that they are all originally offshoots 
from the same species ; more than that, it is not difficult to find examples of each of them, having more or 
less of the characters of the others but in the mass, with the exception perhaps of P. austriaca and P. 
Pallasiana, which are closer together than the others, the difference between them is sufficiently recognisable, 
is 
