SCHWAB, HEIDI C.*, RUTH A. STOCKEY, AND CHARLES E. SCHWEGER. Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Department of Anthropology, University of Alberta, Edmonton, AB T6G 2E9. - Ovulate cones of Picea from the Lower Pliocene Ch'ijee's Bluff, Yukon Territory, Canada.
Large numbers of ovulate cones resembling Picea Dietrich were
recovered from the Lower Pliocene sediments of Unit One of Ch’ijee’s
Bluff on the Porcupine River, Yukon Territory, Canada. Fourteen
structurally preserved cones were sectioned using glycol methacrylate
and bioplastic embedding techniques for anatomical study. Cones are
cylindrical with a slightly tapering apex, 6.7 to 11.2 cm long, 1.9 to
2.8 cm in diameter. Pith and cortex are parenchymatous with scattered
sclerenchyma in the middle and outer cortex. Bract and ovuliferous
scale traces arise separately from the axis stele with a series of
adaxial resin canals. The ovuliferous scale has a V-shaped trace at
its origin while the bract trace is terete and accompanied by two
resin canals. Five to six resin canals in the ovuliferous scale
extend into the abaxial scale sclerenchyma. Bracts are keeled,
6.1-7.3 mm long, with a thin, tapered apex. Elongate, winged seeds
are borne in pairs on the adaxial scale surface. Cones were compared
anatomically to Picea breweriana S. Wats.,P. glauca
(Moench.) Voss,P. engelmannii (Parry) Engelm., and the fossil
taxa P. anadyrensis Krystofovich and P. banksii Hills
and Ogilvie. The Yukon cones most closely resemble Picea
glauca, but differ in the number of resin canals per scale, shape
of the ovuliferous scale trace in transverse section, number of
ovuliferous scales per cone, bract length, and amount of sclerenchyma
in the cortex of the cone axis. These cones represent a new species
of Picea that could easily be confused with P. glauca
which occurs in east central Alaska based on anatomical evidence. Our
results point out the importance of anatomical sectioning in the
documentation conifers from the late Tertiary of the Yukon and Alaska
where similar cones have been recovered.
Key words: conifer, Picea, Pinaceae, Pliocene, seed cones