描述发现于西藏拉萨晚中生代林布宗组的种子蕨化石,确定为新种——西藏叉羽叶Ptilozamites tibeticus Yang sp.nov.。该种有别于其它叉羽叶各种:叶二次羽状;末二次羽轴较粗,具斜向纵纹或瘤状突起;末次羽片披针形,在羽轴上互生;末次羽轴的表面具斜的纵条纹;小羽片在末二次羽轴和末次羽轴上互生至对生,排列规则而紧密。中生代种子蕨类植物主要发现于晚三叠世至早侏罗世地层,新种的发现表明种子蕨类植物在青藏高原可一直延续到早白垩世。 Describing the seed fern fossils discovered in the Late Mesozoic Lin Buzong Formation in Lhasa, Tibet as a new species - Ptilozamites tibeticus Yang sp. Nov. The species is different from other kinds of fork leaves: the second pinnate; the second rachis thicker with oblique longitudinal stripes or knoblike protrusions; the last pinnae lanceolate, alternate on the rachis; the last The surface of the rachis has oblique vertical stripes; the pinnules alternate to opposite on the last two rachises and the last rachises, arranged regularly and closely. Mesozoic seed ferns mainly found in the Late Triassic to Early Jurassic strata, the discovery of new species showed that seed ferns in the Qinghai-Tibet Plateau can be extended to the Early Cretaceous.