USGS11614.5 'Ficus' melanophylla Lesquereux MA97

Notes

 

 

Locality

Locality Map

USGS11614

Lat. 60° 36' 36"N  Long. 164° 49' 18"W

Baird Inlet (C-8) Quad. Nelson Island.

Description

Leaf:  simple (?); symmetrical, narrow ovate to lanceolate; apex (probably attenuate ?) acute; base obtuse; margin entire; venation camptodromous brochidodromous; primary midvein moderate, more or less straight; secondary veins moderate to weak, more or less straight until near margin where they abruptly curve to join superadjacent secondary at an acute angle, secondaries sometimes branched; intersecondaries present, apparently often composite; tertiary veins forming an orthogonal to random reticulum and arches near margin; fourth order arches also present close to margins forming looped ultimate venation, areolation well developed with fourth order veins forming an orthogonal reticulum, areoles usually five-sided, enclosing once or twice branched veinlets

Remarks

Specimens USGS 11614.53 and USGS 11614.46a are considered to represent the same form on the basis of an almost identical venation. The only difference is the presence of very fine veinlets connecting the margin to the ultimate marginal loops.  This feature is by no means clear, however, in specimen USGS 11614.53, and could be a preservation artifact.  Alternatively it may been unobserved in specimen USGS 11614.46 due to inferior preservation.  Until this difference can resolved by examining more specimens, the similarities in other characters strongly suggest these specimens represent the same form.
            Of the many species of 'Magnolia' Linnaeus that have been described from Upper Cretaceous rocks the most similar in form and venation is 'Magnolia' capellini Heer.  This name has been applied to a variety of leaf forms displaying a range of venation patterns and under these circumstances the name is of little value.  Nevertheless, one specimen figured by Berry (1919; Plate 32, Fig. 7) has the same shape and general venation pattern to Form MA97, the main differences appear to be the narrow shape, smaller size, and fewer orders of marginal loops in Form MA97.  Berry points out that there is considerable variety of size and shape, particularly with regard to the apex, in leaves of 'M'. capellini.  Berry also considers 'M'. capellini is less narrow than 'Magnolia' speciosa Heer but there appears to be little in common between Berry's figured specimen of 'M.' speciosa (Berry, 1919; Plate 18, Figs. 3 and 4) and Form MA97.
            'Ficus' melanophylla (Lesquereux, 1892, p. 83; Plate 50, Fig. 2) not only has a similar basal shape, but also apparently has identical venation.  In Lesquereux's specimen and that of Hollick (1930, p. 72; Plate 52, Fig. 2b) the venation is as well preserved as in this specimen.  Lesquereux particularly noted the numerous parallel brochidodromous secondary veins and the intersecondaries (which he called tertiaries) curving to join the secondaries.  The only point of disagreement is that Lesquereux's specimen is supposed to have an obtuse apex.  However, the apex was broken from the rest of the specimen and not figured by Lesquereux so the exact nature of the apex of his specimen remains in doubt.