Qin Min, Wang Deming, Liu Le, Liu Lu, Zhou Yi
College of Life Sciences, Linyi University, Linyi 276000, PR China.
Key Laboratory of Stratigraphy and Palaeontology, Ministry of Natural Resources, Beijing 100037, PR China.
PNAS Nexus. 2024 Jun 15;3(7):pgae241. doi: 10.1093/pnasnexus/pgae241. eCollection 2024 Jul.
The earliest forests in the Devonian were reported from only four localities worldwide. The tree lycopsids, sometimes as the primary elements of Devonian forests, had evolved several types of rooting systems. In recent years, we found and excavated a Late Devonian (Famennian, 374-359 Ma) lycopsid forest from Zhejiang Province, China. The fossil forest occurs at seven locations of Lincheng Town of Changxing County and mainly consists of small tree lycopsid ( gen. et sp. nov.) stems usually connected to lobed cormose rhizomorphs. The four short lobes of each rhizomorph often branch once and bear roots arranged radially. Allometry is observed between the trunk diameter of and the length of its rhizomorphic lobes, indicating that the trunk develops later than the rhizomorph in tree lycopsid plants. The Devonian witnessed the transformation from clastic nonlycopsid dominated forests to Carboniferous swampy forests dominated by giant lycopsid trees. These trees form a multigenerational community, as shown by the preserved stems at various levels within the same area due to frequent sedimentation events.
泥盆纪最早的森林在全球仅四个地点被报道过。乔木石松类植物，有时作为泥盆纪森林的主要组成部分，已经进化出了几种根系类型。近年来，我们在中国浙江省发现并挖掘了一片晚泥盆世（法门期，3.74 - 3.59亿年前）的石松类森林。这片化石森林出现在长兴县林城镇的七个地点，主要由小树状石松类植物（新属及新种）的茎干组成，这些茎干通常与叶状的块状根状茎相连。每个根状茎的四个短叶状部分通常会分叉一次，并着生呈放射状排列的根。在树干直径与其根状茎叶状部分的长度之间观察到了异速生长关系，这表明在树状石松类植物中，树干的发育晚于根状茎。泥盆纪见证了从碎屑岩非石松类植物主导的森林向石炭纪以巨大石松类树木为主导的沼泽森林的转变。这些树木形成了一个多代群落，这一点从同一区域内不同层面保存的茎干可以看出，这是频繁沉积事件所致。
