Locality
USGS11493
69.328° -153.011°
Ikpikpuk River Area, Tommy Creek
17-24 m high bluffs on the east side of Tommy Creek consists of coal beds overlain by a gray bentonitic clay. This is capped by a gray siltstone and conglomerate. Probably representing the Tuluvak Tongue of the Prince Creek Formation, this locality yielded abundant plant debris and some whole leaves from the siltstone.
Description
Leafy shoots: leaves varying in shape from narrow elliptical near shoot apex to linear lanceolate; leaf apex obtuse to rounded angular acute; base rounded decurrent with a small footstalk running obliquely for a short distance along shoot axis, a dark band approximately a quater of the width of the leaf runs centrally along the length of the leaf in a groove; leaf arrangement close near the apex becoming more widely spaced below, phyllotaxy obscure, distichous appearing to be sub-opposite in older shoots.
Remarks
Hollick's (1930, 1936) treatment of the Alaskan fossil coniferous shoots is confused (Seward, 1935; Chaney, 1951) particularly regarding the genus Cephalotaxopsis to which he would probably have assigned these specimens. Chaney considered that most or all of Hollick's material referred to C. heterophylla Holick and C. intermedia was assignable to Torreya as many of the needles show opposite attachment and the needles are too narrowly distally to resemble those of Metasequoia, and should be placed under Hollick's Tumion (Torreya) gracillimum. Chaney further suggested that the foliage Hollick assigned to C. microphylla var. laxa Hollick might also belong to this species but some specimens may represent Taxodium. He hoped additional material would resolve these problems. Krassilov (1979) included Cephalotaxopsis intermedia in the species Parataxodium intermedium (Hollick) Krassilov.
The absence of reproductive material and lack of cuticular features must render any determinations unreliable. The inevitable confusion is compounded in that leaves on these foliage shoots exhibit considerable variation in shape, size, density, and angle of attachment to the shoot. This variation could reflect shoot maturityl or position within the crown or a combination of these factors.
The larger specimens (USGS 11556.94, USHS 11556.41 and USGS 11556.19) have leaves similar in shape to the lower ones of form GCO80. All have acute tips, a narrow ovate shape, a medial longitudinal groove and possess a pronounced foot-stalk. The insertion on the shoot axis is the same, being apparently sub-opposite to alternate but in reality probably reflecting a distichous helical phyllotaxy. the shoots were probably abscissed as complete units and specimen USGS 11556.94 exhibits a pronounced reduction of leaf size towards its base. Such a feature is seen in a specimen of Hollick's assigned to C. heterophylla (USNM 37393; Hollick 1930, Plate 15, Fig. 10). The 'rigidity' of the foliage, a character frequently used by Hollick to distinguish forms, is invalid taxonomically because some specimens (USGS11556.19 and USGS 11556.94) possess both straight and curved leaves.
