爵床科凹苞马蓝在贵州的分布新记录及其补充描述

The new distribution of Strobilanthes retusa (Acanthaceae) in Guizhou with supplementary description

【目的】马蓝属中不少植物具有类似竹类植物的多年生一次性开花现象,但对其研究不多。凹苞马蓝(Strobilanthes retusa D. Fang)是采自广西环江喀斯特地区的标本发表的新种,原记载仅环江有分布,由于标本较少,对其形态特征变异不甚了解。在贵州省茂兰国家级自然保护区发现该种并补充描述,对研究多年生一次性开花现象植物的开花机制具有重要价值。【方法】对凹苞马蓝贵州居群观察其形态特征及开花习性;扫描电子显微镜下观察凹苞马蓝的花粉和种子形态。【结果】凹苞马蓝为贵州新分布新记录,目前仅知分布于广西和贵州交界的喀斯特地区;凹苞马蓝的花粉粒为长球形,极面观多裂圆形,辐射对称,具3孔沟及12~15条假沟,外壁表面具波状纹饰;种子卵形,表面密被螺旋状多细胞长粗毛,基区大。【结论】确认凹苞马蓝是多年生一次性开花植物,根据标本记载推测其开花周期为7~10 a。讨论了凹苞马蓝的亲缘关系,并对凹苞马蓝的形态特征进行了补充描述,提供了线条图和形态照片。

【Objective】In Strobilanthes,several species exhibit the plietesial phenomenon that plants grow for many years,flower gregariously,and then die,in the same manner as bamboos.Strobilantes retusa was described based on materials collected from a Karst area in Huangjiang,Guangxi and the variation in morphology is poorly understood because of the limited material available.The discovery of this species in the Maolan National Nature Reserve of Guizhou Province is of great significance for studying the flowering mechanism of plietesial species.【Method】The morphological characters and flowering habits of S.retusa were observed in the Guizhou population,and the morphology of pollen and seeds was observed using scanning electron microscopy.【Result】S.retusa is restricted to Karst areas at the border of Guangxi and Guizhou,and is newly recorded in Guizhou Province.Pollen grains are prolate and 3-colporate with 12-15 pseudocolpi,and possess undulate exine ornamentation.Seeds are ovate in outline densely spirally multicellular with large areolae.【Conclusion】S.retusa is a plietesial species with a presumed life circle of 7-10 years.The affinity of S.retusa is discussed,and the supplementary morphological description,line drawing,and color photographs are also provided.