Section of Ecology and Evolution, University of California Davis, Davis, California, United States of America.
PLoS One. 2009 Dec 23;4(12):e8346. doi: 10.1371/journal.pone.0008346.
The distribution of Palmer's oak (Quercus palmeri Engelm.) includes numerous isolated populations that are presumably relicts of a formerly larger range that has contracted due to spreading aridity following the end of the Pleistocene.
We investigated a recently discovered disjunct population of Palmer's oak in the Jurupa Mountains of Riverside County, California. Patterns of allozyme polymorphism, morphological homogeneity, widespread fruit abortion, and evidence of fire resprouting all strongly support the hypothesis that the population is a single clone. The size of the clone and estimates of annual growth from multiple populations lead us to conclude that the clone is in excess of 13,000 years old.
The ancient age of the clone implies it originated during the Pleistocene and is a relict of a vanished vegetation community. Range contraction after climate change best explains the modern disjunct distribution of Q. palmeri and perhaps other plants in California.
帕尔默栎（Quercus palmeri Engelm.）的分布包括许多孤立的种群，这些种群可能是过去更大范围的残余，由于更新世末期干旱的蔓延，这些范围已经缩小。
我们研究了加利福尼亚州里弗赛德县朱鲁帕山脉最近发现的帕尔默栎不连续种群。同工酶多态性模式、形态同质性、广泛的果实败育以及火灾再萌发的证据都强烈支持这样一种假设，即该种群是一个单一的克隆。克隆的大小和来自多个种群的年生长估计使我们得出结论，该克隆的年龄超过 13000 年。
克隆的古老年龄意味着它起源于更新世，是一个已经消失的植被群落的残余。气候变化后的范围收缩最好地解释了 Q. palmeri 以及加利福尼亚州其他植物的现代不连续分布。
