A New Lycopsid, Zhenglia radiata gen. et sp. nov., from the Lower Devonian Posongchong Formation of

来源 :Acta Geologica Sinica(English Edition) | 被引量 : 0次 | 上传用户:lisenrui
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A new plant, Zhenglia radiata gen. et sp. nov., from the Posongchong Formation (Early Devonian, Pragian age) of the Wenshan District of southeastern Yunnan Province, China is a small herbaceous lycopsid. The aerial branches divide into foliar and fertile stems. The arrangement of the leaf bases on the stem shows lepidodendroid-like phyllotaxy. Possibly the leaf base bears a ligulate pit. The microphyll consists of a swollen, decurrent base, and an entire, linear lamina. The fertile axis is composed of sporophylls arranged helically, forming a compact area similar to cone-like structure. Each sporophyll consists of a widened lateral extension and a distal lamina. The ovoid-elongate sporangia are attached adaxially on the surface of sporophylls. Based on morphological similarities, especially the undivided microphylls, the style of phyllotaxy, the form of the cone-like structures and sporangia, the new lycopsid Zhenglia radiata is placed in the order Protolepidodendrales and a possible evolutionary relationship with the arborescent lycopsids of the Late Devonian and Carboniferous is considered. A new plant, Zhenglia radiata gen. Et sp. Nov., From the Posongchong Formation (Early Devonian, Pragian age) of the Wenshan District of southeastern Yunnan Province, China is a small herbaceous lycopsid. The aerial branches divide into foliar and fertile stems The arrangement of the leaf bases on the stem shows lepidodendroid-like phyllotaxy. Possibly the leaf base bears a ligulate pit. The microphyll consists of a swollen, decurrent base, and an entire, linear lamina. The fertile axis is composed of sporophylls arranged Each sporophyll consists of a widened lateral extension and a distal lamina. The ovoid-elongate sporangia are attached adaxially on the surface of sporophylls. Based on morphological similarities, especially the undivided microphylls, the style of phyllotaxy, the form of the cone-like structures and sporangia, the new lycopsid Zhenglia radiata is placed in the order Protolepidodendrales and a possible e volutionary relationship with the arborescent lycopsids of the Late Devonian and Carboniferous is considered.
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