268 Wilhelm Bock 1969
and distinct mid-rib, about 0.15-0.2 mm wide, which is nonnally placed on the inside. On the otherwise smooth sudace are occasionally rows of small dots or indentations, about 0.15-0.2 mm in diameter, believed to represent microsporangia. However, most of the leaflets show a smooth sudace, that not all of them are believed to have been fertile (fig. 450). It has been also considered that the prototype of the leaflets fonning the bud and enveloping the ovulate cone are fertile on the inner sudace, suggested by roundish protuberances, which is the case in the cycadeoidean seed cone.
At this point it should be mentioned that the specimen, shown in figs. 442- 447 (type specimen no. 2301) does not disclose megasporangial buds. It is believed to be purely microsporangious and it would be hard to explain the purpose of the bract leaves, should they not have developed microsporangia. It is the bisporangiate type of inflorescence, which shows more often sporangial growth. The second type is represented by the fertile inflorescence, displaying the characteristic buds and seeds (figs. 453 and 454, specimen no. 2302, 2303) but also microphyllous leaflets along the support bracts. A solitary seed found disconnected in the lower portion of the inflorescence (fig. 454) between poorly preserved remmants of bracts, which is similar in shape to those disclosed in the lower portion of the cone, while in the upper portion they appear to become slightly shorter, or are still in the stage of development. In form the seed is more or less a circular segment, probably bilaterally arranged in pairs with a well curved sudace and somewhat blunt-roundish ends. Its length is 7 mm and its maximum breadth 2.7 mm (fig. 457). It is thickest at the straight interior side, where it may have contacted an adjacent seed. About half of the sudace near the roundish side is covered by about 6-7 rows of hemispheric corpuscles, which are placed in pedectly parallel rows to the margin of the seed. Toward the straight segment side they enlarge to a row of closely set, somewhat larger, teeth-like particles or fingers, which occupy a shallow, hollow shelf, indicating the former presence of an integument, about 0.2 mm thick.
Although the whole fossil (fig. 454) is largely a fine sand casting, the vascular system can be quite closely followed, the bract and bud bundles being united rather steep tangentially with the main vascular bundle of the inflorescence stem or axis, amounting to about a total of 50 peripheral units, which can be observed more clearly in fig. 443, displaying at the base a cross section of a broken off stem with an outside impression of the vascular bundles, followed by the actual xylem cylinder (light ring in fig. 451), surrounding a medullary roundish body, about 2.5 mm wide with a cell structure being 0.15-0.2 mm in diameter. Other cell structure is occasionally observed on the sudace of the stem ( fig. 460), identified by a squarish to elongated cell pattern, while microphyllous leaves show a similar outline, being considerably smaller. The epidermal cells of the seed are roundish, about 0.04 mm wide and papillaceous. The rough matrix did not permit any closer identification.
Fig. 445 - Enlargement of fig. 442. 4 bracts covered with fertile leaflets (microsporophylls), x 5.
Fig. 446 - Enlargement of fig. 442. Attachment of fertile leaves (microsporophylls) attached to bract surface, x 18.
Fig. 449 - Reconstruction; part of fig. 442. Fertile bract with female flower bud and attachment surface of bract. Second bract with lengthwise vascular grooves, interrupted by roundish indentation for vascular entrance to flower buds, x 3.
Fig. 450 - Reconstruction; part of fig. 442. Attachment of male, fertile leaflets ( microsporophylls) with mid-line and rows of sporangia to bract, x 20.
Fig. 451 - Enlargement of inflorescence stem cross section (fig. 442), disclosing vascular and medullary cylinder, x 4.
Fig. 452 - Triassiflorites grandiflora, n. sp. Drawing of bract with sub-bracts; spec. 2335, x 1.5.