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首页> 外文期刊>Bothalia: African Biodiversity & Conservation >Pollen and reproductive morphology of Rhigiophyllum and Siphocodo (Campanulaceae): two unique genera of the fynbos vegetation of South Africa
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Pollen and reproductive morphology of Rhigiophyllum and Siphocodo (Campanulaceae): two unique genera of the fynbos vegetation of South Africa

机译：根茎植物和菊科（桔科）的花粉和生殖形态：南非的蕨类植物植被的两个独特属

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Pollen grains of Rhigiophyllum squarrosum Hochst., Siphocodon spartioides Turcz. and S. debilis Schltr., are flattened and triangular with pores at the angles. This morphology is radically different from known pollen of the Campanulaceae s.sfr:: the Campanulaceae are treated here as a family separate from the Lobeliaceae, Cyphiaceae, Nemacladaceae, Pentaphragmataceae and Sphenocleaceae (Lammers 1992). As traditionally conceived, the Campanulaceae is very heterogeneous and, in many classifications, these families were treated as subfamilies of a much-enlarged Campanulaceae. The consistently different floral morphology, biochemistry and pollen structure of the Lobeliaceae favours the recognition of this predominantly tropical group as a separate family.The pollen grains of these species are described in comparison with other members of the Campanulaceae. Based on surface characteristics of their pollen grains, we conclude that they represent an early offshoot o f the wahlenbergioid line-age in southern Africa. We suggest that this unique pollen may also be the result of a highly selective regime in the fynbos, associated with specialized pollinators, and base-poor soils, in addition to possible adaptations for ant dispersal and fire. Rhigiophyllum Hochst. and Siphocodon Turcz. are also unique in having free carpel-like structures within the ovary. These shrink to form seed pockets around the seeds and disperse as units when the capsule matures. Data from molecular studies support the contention that these taxa form a sister group to all other wahlenbergioids and that this should be formally recognized in a classification system. We treat Rhigiophyllum and Siphocodon within the Campanulaceae: Wahlenbergioideae, as a separate tribe, the Rhigiophylleae tribus nov., the species of which are distinguishable from other wahlenbergioids by unique angulaperturatc pollen, epipetalous stamens, free carpel-like structures and seed pockets.??
机译：Rhigiophyllum squarrosum Hochst。，Siphocodon spartioides Turcz的花粉粒。和S. debilis Schltr。变平并成三角形，并在角度处有孔。这种形态与桔梗科的已知花粉完全不同：：桔梗科在这里被视为与山梗菜科，蓝藻科，线虫科，五叶草科和蝶科分开的一个家族（Lammers 1992）。按照传统的设想，桔梗科是非常异类的，在许多分类中，这些科被视为桔梗科的一个大家族。半边莲科的花形态，生物化学和花粉结构始终不同，这有利于将这个主要为热带的群体作为一个独立的家族来识别。与桔梗科的其他成员相比，描述了这些物种的花粉粒。根据花粉粒的表面特征，我们得出的结论是，它们代表了南部非洲Wahlenbergioid世代的早期分支。我们建议，这种独特的花粉可能是由于雌蝇的高选择性机制，与专门的传粉媒介和基础贫瘠的土壤相关联的结果，此外还有可能对蚂蚁的散布和火势进行了适应。菱角霍赫斯特。和Siphocodon Turcz。在卵巢内具有游离的心皮状结构方面也很独特。这些会收缩，在种子周围形成种子袋，并在胶囊成熟时作为单位分散。来自分子研究的数据支持这样的论点，即这些类群与所有其他类鞭毛类动物组成一个姊妹群，并且应该在分类系统中予以正式承认。我们将桔梗科中的根瘤菌属和硅藻类作为一个单独的部落对待，其中根瘤菌属植物是新的，其中根瘤菌属的花粉，花epi雄蕊，游离的心皮状结构和种子袋与其他根茎类植物有区别。

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