ves. Moreover its cone, so far as I can learn, is not yellow
at maturity, but brown.

Plate XXIII.

Figs. 208, 209, Three cones. Fig. 210, Leaf-fascicle and magnified
leaf-section.

[Illustration: PLATE XXIII. P. MERKUSII (198-200), SINENSIS (201-207),
INSULARIS (208-210)]

=XI. AUSTRALES=

Pits of the ray-cells small. Leaf-hypoderm biform or variable.
Spring-shoots uninodal in some, multinodal in other species. Cones
dehiscent at maturity.

This group combines the dehiscent cone of the Lariciones with the
wood-anatomy of the serotinous Pines. Also the multinodal spring-shoot
first appears here and is gradually developed among the species,
absent in Nos. 37-39, sometimes present in Nos. 40-43, and prevalent
in Nos. 44-47.

All the species are of the Western Hemisphere, and among them may be
found the biform hypoderm of the leaf, the internal resin-duct, and
the total absence of external resin-ducts, characters common in
American Hard Pines. The eastern species are quite constant in their
characters and present no varietal forms; the western species, on the
other hand, are very variable. This difference may be due to the even
level and slight climatic differences of the Atlantic states and to
the remarkable diversity of altitude and climate of the western states
and Mexico.

Outer walls of the leaf-endoderm thick.
Cones large, attaining 12 cm. or more in length.
Prickles of the cone inconspicuous.
Bark-formation late 37. pseudostrobus
Bark-formation early 38. Montezumae
Prickle of the cone conspicuous 39. ponderosa
Cones small, 7 cm. or less in length 40. teocote
Outer walls of the leaf-endoderm thin.
Spring-shoots mostly uninodal.
Prickle of the cone slender, sometimes deciduous.
Cones mostly oblique 41. Lawsonii
Cones symmetrical 42. occidentalis
Prickles of the cone stout and persistent 43. palustris
Spring-shoots multinodal.
Resin-ducts internal 44. caribaea.
Resin-ducts mostly medial.
Prickle of the cone stout 45. taeda
Prickle of the cone slender.
Bark-formation late 46. glabra
Bark-formation early