Fróðskaparrit - 01.01.1963, Side 81

Fróðskaparrit - 01.01.1963, Side 81
Fossil Metasequoia From Mikines, Faroe Islands 87 with the rock in question which is so crowded with plant impressions, that the shale becomes extremely fissile. There* fore some pieces could easily have been Iost. Some other specimens (No. 7, 10, A, B, C, D and G) (Pl. 1, figs. 2, 3) also contain parts of long shoots with or without short shoots attached. For instance, specimens A, B, C show short shoots, disposed in pairs, while the specimen no. G shows only a fragment of a long shoot. The long shoots carry leaves between the nodes. These leaves are remote, linear, short petiolate and obtusely rounded terminally and basally. The Ieaves have relatively large decurrent bases and are opposite, or a Ieaf may be oppo= site a short shoot. Their average dimensions are: length 10 mm, width: 1,7 mm. The axes of the long shoots show the impressions of more or less distinct, obliquely decurrent leaf bases which successively overlap from right and left in the manner characteristic of Metasequoia. In addition, the long shoots show opposite short shoots or their scars. But the phyllotaxy is best studied on the short shoots. Well preserved short shoots (which are numerous in the collection) demonstrate that the leaves are opposite and apparently distichous (i. e. no. 11) (Pl. 1, 2). Just as observed on the recent Metasequoia glyptostroboides Hu &. Cheng, the pattern of the leaf bases demonstrates that the distichous arrangement is only apparent and that originally it was decussate. This can be definitely confirmed by studying the well preserved specimens in this collection (No. 11, 13) (Pl. 1, figs. 1, 3, 4). The characteristic zig* zag pattern on the impression of the axis of the short shoots results from the obliquely decurrent bases of the opposite leaves which are decussately arranged. The leaves of the short shoots are closely spaced, short petiolate, linear and obtusely rounded terminally and basally. They have strong, obliquely decurrent bases which enclose the axis and even overlap most of the base of the opposite leaf. In a succession of opposite leaf pairs this successive over*
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