title: Pollen Organ Telangiopsis sp. of Late Devonian Seed Plant and Associated Vegetative Frond.
abstract: Pollen organ Telangiopsis sp., associated with but not attached to vegetative fronds, has been collected from the Upper Devonian (Famennian) Wutong Formation, Dongzhi County, Anhui Province, China. Fertile axes with terminal pollen organs are dichotomous for 2-4 times and may be proximally attached by fragmentary pinnules. Pollen organs are synangiate and borne on the top of a short stalk. Synangia are radial in symmetry and each consists of 4-8 elongate microsporangia fused at base. Microsporangia have a longitudinal dehiscence line and show a tapered apex. The associated stem is spiny and bears a vegetative frond which bifurcates once at the basalmost part. Frond rachises possess one order of pinna arranged alternately. Pinnules are borne alternately, planate, highly dissected, and equally dichotomous for 2-3 times. Comparisons among Late Devonian seed plants recognize several branching patterns in the fertile fronds/axes bearing terminal pollen organs. Telangiopsis sp. reinforces that the Late Devonian pollen organs are synangiate usually with basally fused microsporangia. It is suggested that the evolutionary divergence of radial and bilateral symmetries of pollen organs may have occurred in the Famennian, when the earliest seed plants evolved planate and sometimes laminate pinnules.
authors.affiliation: Key Laboratory of Orogenic Belts and Crustal Evolution, Department of Geology, Peking University, Beijing 100871, China.
authors.forename: De-Ming
authors.initials: DM
authors.lastname: Wang
authors.affiliation: Science Press, China Science Publishing & Media Ltd., 16 Donghuangchenggen North Street, Beijing 100717, China.
authors.forename: Mei-Cen
authors.initials: MC
authors.lastname: Meng
authors.affiliation: Department of Geology, School of Resource Environment and Earth Science, Yunnan University, Kunming 650091, Yunnan Province, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Guo
mesh_terms: D018514:Plant Structures; D011058:Pollen; D012639:Seeds