Pollen morphology of the native Rutaceae species from Argentina

The pollen morphology of 13 native taxa of the Rutaceae from Argentina was studied under optical and scanning electron microscopy to provide new data that would allow delimiting these taxa. The species considered were Balfourodendron riedelianum, Esenbeckia densiflora, E. febrifuga, E grandiflora, Helietta apiculata, Pilocarpus pennatifolius, Zanthoxylum caribaeum, Z. coco, Z. fagara, Z. petiolare, Z. rhoifolium, Z. riedelianum and Zanthoxylum rigidum ssp. hasslerianum. The general morphological characteristics of the pollen grain of these species are: radiosymmetric, isopolar; small, medium or large size; 3-colporate or 4-colporate; colpus with costa colpi; semitectate (reticulate, striate reticulate or striate). Sculpture, shape and size are the main characters that allow differentiating the studied taxa. Morphological characters among the species are discussed and a species key is presented.