314 Wilhelm Bock 1969
side close to the seeds, while the other side is strongly sclerotized, proceeding in a single layer toward the apophysis, which is roughly rhomboidal, divided medial-horizontally by a ridge, about 15 mm long, forming in the central portion a much smaller, umboidal, rhomboid area, 3 mm long. In this area all bundles make a sudden turn from the interior scale surface to the opposite side in a sharp curve. At the same time they converge toward the umbo area, divided by the medial ridge, where they form club-like ends and abruptly terminate. The sudden termination prevents them from penetrating to the end of the scale, although they appeared to cross the scale gradually from the inner to the outer side. The location of the termination may have been chosen for reasons of exudation, but it is probable that procedure of the bundles.indicates singleness of this scale component.
There are also a number of living araucarian species, which possess a pronounced apophysis, notably Araucaria brasiliensis and A. cunninghamii. The umbo of the latter terminates in a distinct spine, which is part of the bract scale, although it is not clear, whether the sterile section of the seed scale is involved. In the more ancient one such as the Permian Walchiaraucaria permiensis (fig. 519) the bract and the sterile scale may have contributed to the structure of the apophysis, the central point of the letter becoming already reasonably distinct. Later on, it may have developed into a protective device, which is most forcefully proven by the strong, horn-like attachment of the Californian Pinus coulteri.
The evidence of complete seed scale units in Primaraucaria (fig. 528) is quite restricted, largely because of the persistence of its exterior scale armor, which failed to easily disintegrate, contrary to those of living araucarians. Only in the lower sections of larger and older female cones could a small amount be examined. A number of scale units from various megastrobili are comprised in fig. 544, pennitting a fairly reliable approach to their structure, though by no means complete. The apophysis pictured in fig. 533 is largely rhomboidal with its upper margin sometimes rounded. Occasionally, they are squarish and deformed by pressure. They are easily recognized by a horizontal, diagonal, slightly protruding, or overhanging lip, forming a medial line, dominated centrally by a small, flat or pointed umbo. From the latter a number of lesser rays may radiate toward the margin of the slightly pyramidal, outstanding apophysis. The epidermal surface of the armor shields is also characteristic for this species, consisting of wavy, minutely granulated lines or ridges (fig. 546).
It was not possible to identify clearly the contact between bract and seed scale as side views were not available, or the distinct presence of a sterile section. It appears reasonable, however, to accept the view that in Triassic time seed scale, bract scale and fertile components were already well fused. Scrutinizing various shapes disclosed in fig. 544, it becomes obvious that the seed bearing scale of this species expands its rather long stalk portion gradually into a somewhat club-shaped upper section, terminating in an apical point. The upper section contains a deep insertion of a narrow longitudinal impression, on which a part of the seed, or its imprint, is still noticeable. The whole seed scale unit resembles that of the Permian Walchiaraucaria (figs. 521-526), particularly in the deep placing of the seed and the two marginal, bulging seed scale sections, which unite further below at its junction with the scale stalk. There are at least 6 vascular bundles in the Triassic specimens involved, because they can be detected from a broken stalk and are otherwise clearly detectable by surface ridges.