PREMISE Seed dispersal is extremely important for the recovery and restoration of forest communities. Relict tree genus Zelkova possesses a unique dispersal mechanism: mature fruits fall with the entire twig, and the dried leaves that are still attached function as a drag-enhancing appendage, carrying the fruits away from the parent tree. This singular adaptation has never been investigated in Z. abelicea. METHODS Drop tests with dispersal units and individual fruits of Z. abelicea were performed in controlled conditions to measure their dispersal velocity and to define their flight mode. RESULTS Zelkova abelicea uses both slowly falling dispersal units with chaotic motion, as well as fast falling individual fruits using a straight path. The falling velocity of Z. abelicea dispersal units is 1.53 m s-1 , which is virtually identical to that of the East Asiatic Z. serrata (1.51 m s-1 ). In contrast, the falling velocity of individual fruits was 2.74 m s-1 (Z. serrata: 5.36 m s-1 ). CONCLUSIONS Members of the genus Zelkova, growing today in distant regions, show remarkable evolutionary conservation of the velocity and flight mechanics of their dispersal units. This is surprising because the Mediterranean and East Asiatic Zelkova species have been separated at least 15-20 mya. Zelkova abelicea, although growing in the Mediterranean with completely different forest structure and composition, still uses the same dispersal mechanism. The dispersal capacity of the genus Zelkova is less efficient than that of other wind dispersed trees, and it presumably evolved for short-distance ecological spread and not for long-distance biogeographical dispersal.

中文翻译：

---

榉树中下降扩散单元的速度：椴树属内显着的进化保护

前提 种子传播对于森林群落的恢复和恢复极为重要。椴树属榉树具有独特的传播机制：成熟果实随整枝落下，仍然附着的干叶作为增阻附属物，将果实从母树上带走。这种奇异的适应从未在 Z. abelicea 中进行过研究。方法 在受控条件下对 Z. abelicea 的散布单元和单个果实进行跌落试验，以测量它们的散布速度并定义它们的飞行模式。结果 榉树 abelicea 使用具有混沌运动的缓慢下落的分散单元，以及使用直线路径快速下落的单个果实。Z. abelicea 分散单元的下落速度为 1.53 m s-1 ，这实际上与东亚锯齿状锯缘青蟹 (1.51 m s-1 ) 相同。相比之下，单个果实的下落速度为 2.74 m s-1 (Z. serrata: 5.36 m s-1 )。结论 如今在遥远地区生长的榉树属成员，其散布单位的速度和飞行力学表现出显着的进化守恒。这是令人惊讶的，因为地中海和东亚的榉树物种已经分离了至少 15-20 mya。榉树 abelicea 虽然生长在地中海，森林结构和组成完全不同，但仍然使用相同的传播机制。榉树属的传播能力不如其他风传播树木的效率低，它可能是为短距离生态传播而不是长距离生物地理传播而进化的。