Locality
Locality USGS 11600, Chignik Area, Floodplain swamp depositional environment. Lower part of Tolstoi Formation.
Description
Leaf: simple; symmetrical; ovate; apex acute to attenuate; base rounded with a decurrent junction to the petiole; petiole normal; margin dentate, teeth small (approximately 1 mm in length) with acute to attenuate or spinose apices often curved over in an apical direction; wide rounded sinuses, spacing and size more or less regular, margins sometimes revolute, margin entire near the extreme base; venation appearing pinnate simple craspedodromous; midvein moderate more or less straight; pectinal veins weak, slightly uniformly curved, departing midvein at 30-40°, terminating at margin approximately halfway between base and apex; abmedials departing pectinal at 40o curved, sometimes forked near margin, craspedodromous; superior secondary veins moderate, shallowly uniformly curved, approximately 11 pairs arranged opposite or alternate, arising at angles of 30-40°, more or less parallel and branching up to three times near the margin on both ad- and abmedial sides; the most apical of inferior secondary veins departing midvein at 60-70°, branched abmedially, curved, abmedial branches sometimes forked, sometimes looped, semicraspedodromous, the more basal inferior secondaries looped, recurved, the most basal pair giving off looped veins of third order strength on their abmedial (basal) side; tertiary veins percurrent convex, straight or sinuous, usually joining both ad- and abmedial sides of the secondary veins at right angles but sometimes with an obtuse angle on the admedial side, and an acute angle on the abmedial side; fourth order veins transverse straight or sinuous, veins of fourth order strength departing from the looped veins near the basal margin to run into the midvein of the teeth.
Remarks
The venation of this specimen is almost identical to that of 'Ficus' planicostata var. magnifolia Knowlton (1922; Plate 10, Fig. 3), the only difference being the basal origin of the two strong secondaries. Knowlton's leaf has the same texture and apparently revolute margins. Unfortunately Knowlton's specimen has not been examined directly and strict comparisons cannot be made. The weak pectinal veins do not always arise from the same point opposite one another on the midvein (see specimen USGS 11600.4) and are considerably weaker than the midvein at their point of departure.
In spite of the strong pinnate appearance the venation is probably basically palmate. Pinnate venation is presumed to arise frequently by suppression of the lateral primaries (pectinals) of palmately veined leaves (Hickey and Wolfe, 1975) and occurs in many orders within the Hamamelididae including some (Fagales and Hamamelidales) which also contain species with Spinose toothed leaves. Spinose teeth also occur in the Ranunculidae (Berberidaceae and Papaveraceae) and the Rosidae but these leaves are basically pinnately compound and in the Ranunculidae often possess a fimbrial vein. The Flacourtiaceae also exhibit the Spinose tooth as well as weak or incipient actinodromous venation and semicraspedodromous secondaries (see the base of specimen USGS 11600.4). The tertiary veins do not show the strong concentric arrangement about the petiole which is typical of the palmate Dilleniidae but this may not be significant.
The most likely affinities for these leaves are with the Hamamelidales (compare with Corylopsis spicata Siebold and Zuccarini and C. veitchiana Bean) both of which possess Spinose teeth, or with the Flacourtiaceae which is generally recognized as possessing the most primitive characteristics within the Violales, which in turn is not far removed from the dilleniid stem (Hickey and Wolfe, 1975).