Ehretia pranomiana sp. nov. (Boraginales: Ehretiaceae), a new scrambler from Thailand

Ehretia pranomiana sp. nov. is illustrated and described from northern and south-western Thailand. The new species is similar to E. macrophylla and E. acuminata by having elliptic leaves with a serrate margin, but can be distinguished by its scrambling shrubs, leaf blades with densely hispid, corymbose inflorescence with 4–10 flowers, the corolla with erect lobes and the calyx longer than fruit at maturity. An updated species identification key is provided.
Methods
Specimens from AAU, ABD, BK, BKF, BM, CMU, E, K, KKU, L, QBG and SING were consulted (abbreviations following Thiers, 2022). Species delimitation was examined by consulting relevant literature: Clarke 1885, Gagnepain and Courchet 1914, Johnston 1951, Zhu et al. 1995, Riedl 1997, Mill 1999, Kress et al. 2003. All morphological characters were described using the terminology presented by Weberling (1992). Qualitative observations and measurements were made from the specimens, and descriptions and illustrations were prepared using these data. Distribution, ecology, and phenology were recorded from specimen labels and fieldwork. The collection sites were imported into SimpleMappr (Shorthouse 2010) to create a distribution map. GeoCAT (Bachman et al. 2011) was used to calculate the area of occupancy (AOO) and extent of occurrence (EOO). Preliminary conservation assessments were prepared using the Categories and Criteria of IUCN Standards and Petition Committee (2019).

本次研究对产自泰国北部与西南部的厚壳树属新种（Ehretia pranomiana sp. nov.）进行了形态描述并附绘图。该新种与大叶厚壳树（E. macrophylla）、渐尖厚壳树（E. acuminata）形态相近，三者均具椭圆形叶片与锯齿状叶缘，但该新种可通过以下特征与二者区分：为攀援灌木、叶片密被硬毛、具4-10朵花的伞房状花序、花冠裂片直立，且成熟时花萼长于果实。本研究同时提供了更新后的物种鉴定检索表。

材料与方法
本研究查阅了AAU、ABD、BK、BKF、BM、CMU、E、K、KKU、L、QBG及SING馆藏的标本（标本馆缩写标准遵循Thiers, 2022）。通过查阅相关文献开展物种界定工作，涉及文献包括：Clarke 1885、Gagnepain与Courchet 1914、Johnston 1951、Zhu等1995、Riedl 1997、Mill 1999、Kress等2003。所有形态性状均采用Weberling (1992)提出的专业术语进行描述。基于馆藏标本完成定性观察与性状测量，并以此为基础撰写物种描述、绘制形态插图。物种的分布、生境及物候信息均源自标本标签与野外调查数据。将标本采集点导入SimpleMappr（Shorthouse 2010）以制作物种分布地图。利用GeoCAT（Bachman等2011）计算占用面积（Area of Occupancy, AOO）与发生范围（Extent of Occurrence, EOO）。参照国际自然保护联盟（IUCN）标准与请愿委员会（2019）的等级与判定标准开展初步的保护价值评估。