Abstract

Studies have shown that Acacia Mill. sensu lato consists of seven genera (Acacia sensu stricto, Acaciella Britton & Rose, Mariosousa Seigler & Ebinger, Senegalia Raf., and Vachellia Wight & Arnott) but does not constitute a monophyletic group. The Senegalia sensu lato clade, which corresponds to the genera Acaciella, Mariosousa, and Senegalia sensu stricto, likewise does not constitute a monophyletic group. The pollen morphology of a total of 22 species of Senegalia that occur in Brazil, and that of representatives of the genera Acaciella, Parasenegalia, Mariosousa, and Vachellia, is analyzed here. Pollen material was obtained from exsiccata deposited at some herbaria of Brazil. The pollen was acetolyzed and analyzed using both light and scanning electron microscopy. The dispersal units (polyads) were generally medium to large sized. All of the Senegalia species studied had apolar pollen grains organized in polyads comprising 16 pollen grains. The number of pollen grains in polyads is a synapomorphic character for recognizing those genera. Acaciella polyads have eight pollen grains; Parasenegalia and Mariosousa polyads have 16 pollen grains, and Vachellia polyads have more than 32 pollen grains that are irregularly arranged. The sexine and nexine had identical thickness in most of the species analyzed. Exine ornamentation varied from rugulate to rugulate-perforated to psilate-perforated.

摘要

研究表明，金合欢磨。意义上拉托由7个属（金合欢属狭义，Acaciella的Britton＆玫瑰，Mariosousa Seigler＆埃宾杰，Senegalia的Raf，和Vachellia怀特＆亚诺特），但不构成单系类群。所述Senegalia意义上拉托进化枝，其对应于属Acaciella，Mariosousa和Senegalia狭义，同样不构成单系类群。分布于巴西的塞内加利亚共22种花粉形态及各属代表的花粉形态此处分析了Acaciella、Parasenegalia、Mariosousa和Vachellia。花粉材料是从存放在巴西一些植物标本馆的 exsiccata 中获得的。使用光学和扫描电子显微镜对花粉进行乙酰水解和分析。分散单元（聚合体）通常为中型到大型。所有的Senegalia研究的物种曾在包括16个花粉粒多分组织非极性花粉粒。多聚体中花粉粒的数量是识别这些属的突触特征。Acaciella polyads 有八个花粉粒；Parasenegalia和Mariosousa polyads 有 16 个花粉粒，而Vachellia多聚体有超过 32 个不规则排列的花粉粒。在所分析的大多数物种中，性线和联线具有相同的厚度。外壁装饰从皱褶到皱褶穿孔，再到psilate 穿孔。