GENERA OF TAXACEX AND CONIFERS. 390 
dehisce transversely, and havea knobbed connective. The pollen- 
cells resemble those of Pinus. The ripe female cones are erect, 
the bracts at first longer than the scales, which latter, when ripe, 
fall away with the seeds from the central axis or core, which re- 
mains on the branch erect and bare long after the scales have 
fallen. ‘fo some of these characters there are occasional excep- 
tions, but on the whole the genus is well marked. 
A section of a young rootlet of Abies Pinsapo shows no hypo- 
derm, but a thick cortex limited by an endoderm, a circular 
pericycle enclosing a central triangular mass with xylem at the 
angles and phloem in the intervals. In the centre is a central 
resin-canal. 
In the hypocotyl the section of the bundle is circular, the 
xylem, in the form of a ring, with disconnected masses of phloem 
outside. No resin-canal is apparent in the central pith. 
The cotyledons of A. Pinsapo have the midrib prominent 
on the upper surface, no hypoderm, a single bundle with a 
circular section and of the usual construction. The resin- 
canals are in the lower parenchyma of the cotyledon near the 
epiderm. 
The structure of the adult leaves is well known. For syste- 
matic purposes the relative position of the resin-canals is the 
most important point, their position being either close to the 
epiderm, or in the substance of the leaf-cortex, or close to the 
pericycle. The existence and degree of development of the 
hypo- or exoderm is by no means so useful, being dependent on 
local conditions. 
The species of Abies have, broadly speaking, the same distri- 
bution as those of the genus Pinus (see pp. 87, 38), but do not 
enter the Tropics even on the mountains. The genus is not 
represented in China, and only one species. occurs in Canada. 
Their geological distribution also seems to have been very similar. 
One species is recorded from the Wealden. 
PsEUDOTSUGA. 
A genus established by Carriére, ‘ Traité Général des Coni- 
_féres,’ édit. 2, p. 256 (1867), to include the noble Douglas Fir. 
Though closely allied to Abies and to Picea, the Douglas Fir does 
not fit in well with those or any of the other established genera. 
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