| 名稱 橡樹化石 | Name Oak fossil |
| 地質年代 始新世 | Geological Age Eocene, Bagshot Beds, Pipe Clay Series |
| 描述 遼東櫟（Quercus hiholensis）是殼斗科（Fercaceae）屬Quercus中已經滅絕的一種橡樹。華盛頓中部發現的中中新世化石可以發現櫟屬（Quercus hiholensis）。 Q. hiholensis橡子的大小範圍從4乘4.3毫米（0.16乘0.17英寸）到15.3乘18.8毫米（0.60乘0.74英寸），在一些堅果的尖端有一個umbo，但在其他堅果上沒有。在二十六個確定的Q. hiholensis橡子中，只有一個標本有從堅果中出現的堅果，而在其他標本中只有花被和样式，或者是umbo。外殼的外部包括螺旋排列的刻度，其具有紙質尖端並且範圍高達2.8mm（0.11英寸），紙質尖端進一步延伸至1.4mm（0.055英寸）。該杯狀物具有散佈在其中的硬化斑塊，其中一些硬鱗片與鱗片基部相關聯，組織成白色星形斑塊。果實具有卵形到卵圓錐形狀，尺寸在2.7×2.6mm（0.11×0.10英寸）至9×10.9mm（0.35×0.43英寸）之間。較小，較不成熟的果實表現出獨特的風格和花被結構。這些風格有喇叭形尖端，很短，而花被有明顯的葉片，與風格緊密相連。對於櫟屬部分的橡子來說，最年輕的標本仍然有中止的第二胚珠，並且在發育中的果實基部附近存在分隔的隔膜。 | Descriptions Quercus sp. (Very Rare) Eocene, Bagshot Beds, Pipe Clay Series Collected in the Victorian era is this very rare plant leaf which was related to the modern oak. This specimen is preserved in “Pipe Clay” which was used in making pipes. This site no longer exists as it is buried beneath the promenade, thus making specimens extremely sought after. Size: Length of Leaf 50mm Quercus hiholensis is an extinct species of oak in the Fagaceae genus Quercus. Quercus hiholensis is known from Middle Miocene fossils found in Central Washington. Q. hiholensis acorns range in size from 4 by 4.3 mm (0.16 by 0.17 in) to 15.3 by 18.8 mm (0.60 by 0.74 in) with an umbo on the tip of some nuts, but absent on others. Of the twenty-six identified Q. hiholensis acorns, only one specimen has a nut emerging from the cupule, while in the others only the perianth and styles, or umbo show. The exteriors of the cupules comprise helically arranged scales that have a papery tip and range up to 2.8 mm (0.11 in) with the papery tip extending up to 1.4 mm (0.055 in) further. The cupule has patches of sclereids scattered through it with some of the sclereids that are associated with scale bases organized into white star shaped patches. The fruits have an ovoid to ovoid-conical shape, ranging between 2.7 by 2.6 mm (0.11 by 0.10 in) to 9 by 10.9 mm (0.35 by 0.43 in) in size. The smaller, less mature fruits show the distinct structuring of styles and perianth. The styles have flared tips and are short, while the perianth has distinct lobes that are closely placed to the styles. As is typical for acorns of section Quercus, the youngest specimens still have the aborted second ovule and dividing septum present near the base of the developing fruit. |
| 地點 多塞特, 英國 | Location Bournemouth, Dorset, UK |
| 參考Reference 1. Borgardt, S. J.; Pigg, K. B. (1999). “Anatomical and developmental study of petrified Quercus (Fagaceae) fruits from the Middle Miocene, Yakima Canyon, Washington, USA”. American Journal of Botany. 86 (3): 307–325. Archived from the original on 2017-05-10. Retrieved 2016-12-28. | |
| 編者 由 3B (15) 梁靖 於 1/6/2018 編寫 3E (3) 周子晴 於31/5/2019最後編改 | Editor Created by 3B (15) Leung Natalie on 1/6/2018 Last modified by 3E (3) Chow Tsz Ching on 31/5/2019 |
