A new liverwort with perichaetium and perigonium collected from the Middle Jurassic Yima Formation is described. Gametopbyte is dorsivental, irregularly branched, bearing two-ranks of lateral leaves obliquely attached...A new liverwort with perichaetium and perigonium collected from the Middle Jurassic Yima Formation is described. Gametopbyte is dorsivental, irregularly branched, bearing two-ranks of lateral leaves obliquely attached to main axis, and one rank of ventral leaves transversely attached to ventral surface of the axis. Lateral branch bearing perigonium arises from axil of ventral leaves. Perigonium consists of small paired perigonial bracts arranged in a spike. Two perichaetia are borne on the top of lat- eral branches with an ovate perianth bearing longitudinal ridges and grooves. Setae are thin and straight and stretch out from the aristulate perianth mouth. General morphology of this fossil bears resemblance to some living liverworts of Jungermanniales. It is so far the oldest fossil record of Jungermanniales in the world.展开更多
基金supported by Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KZCX2-YW-154)National Basic Research Programme of China (Grant No. 2006CB701400)
文摘A new liverwort with perichaetium and perigonium collected from the Middle Jurassic Yima Formation is described. Gametopbyte is dorsivental, irregularly branched, bearing two-ranks of lateral leaves obliquely attached to main axis, and one rank of ventral leaves transversely attached to ventral surface of the axis. Lateral branch bearing perigonium arises from axil of ventral leaves. Perigonium consists of small paired perigonial bracts arranged in a spike. Two perichaetia are borne on the top of lat- eral branches with an ovate perianth bearing longitudinal ridges and grooves. Setae are thin and straight and stretch out from the aristulate perianth mouth. General morphology of this fossil bears resemblance to some living liverworts of Jungermanniales. It is so far the oldest fossil record of Jungermanniales in the world.
