The bark of the late triassic Araucarioxylon arizonicum tree from Petrified Forest National Park, Arizona
The bark of the late triassic Araucarioxylon arizonicum tree from Petrified Forest National Park, Arizona
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DOI：
10.1163/22941932-90000371
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发表时间：
2004-01-01
期刊：
影响因子：
1.9
通讯作者：
Savidge, RA
中科院分区：
文献类型：
--
作者：
Ash, SR;Savidge, RA
本文描述了地质记录中唯一已知的非带状树皮。树皮附着在Araucarioxylon arizonicum树的分支上，该树最近在亚利桑那州的晚三叠世Chinle组（类似于220 Mya）中被发现。在化石中，维管圆柱体几乎完全被2-11毫米厚的粗糙树皮所包围。内部树皮厚度小于1毫米，包括一个非常狭窄的区域，推测韧皮部含有罕见的纤维。外部树皮的厚度变化可达10毫米，由无膨大组织和树脂道的南洋杉的弯曲透镜组成，但与南洋杉的带状树皮完全不同。在皱皮层中，薄壁细胞呈放射状排列，薄壁细胞呈矩形，薄壁细胞呈海绵状排列，厚壁细胞呈小簇状排列，厚壁细胞呈单细胞排列。维管形成层有1-4个纺锤形。每个径向文件的单元数。单列射线在次生木质部中常见，并延伸到形成层区。小（直径1毫米），简单的隧道在树皮和木材表明，分支的植食性昆虫的攻击。一个可能的石化甲虫幼虫类似的形式和大小的Anobium是与这些隧道。
This paper contains a description of the only known non-banded bark in the geologic record. The bark is attached to a branch of the Araucarioxylon arizonicum tree that was found recently in the Late Triassic Chinle Formation (similar to 220 Mya) in Arizona. In the fossil the vascular cylinder is almost totally enclosed in rough bark 2-11 mm in thickness. The inner bark is less than 1 mm thick and comprises a very narrow zone of presumed phloem containing infrequent fibers. The outer bark varies in thickness up to 10 mm, and consists of curving lenses of sequent periderm free of both dilation tissue and resin canals but is quite unlike the banded bark of Araucaria heterophylla. Wide zones of very thin-walled rectangular parenchyma cells arranged in radial files and groups of thin-walled spongy parenchyma, and small clusters as well as solitary sclerenchyma occur in the rhytidome. The vascular cambium contains 1-4 fusiform. cells per radial file. Uniseriate rays are common in the secondary xylem and extend to the cambial zone. Small (1 mm in diameter), simple tunnels in the bark and wood indicate that the branch was attacked by phytophagous insects. A possible petrified beetle larva similar in form and size to Anobium is associated with these tunnels.