THE POLEN PAULLINIEAE (SAPINDACEAE)

Abstract

A detailed study on the morphology of pollen on thirty one species of the tribe Paulliniieae, comprising seven genera, has been carried out by LM and SEM.The pollen grains of the following taxa were examined: subtribe Paulliniinae (Cardiospermum L., 4 spp., Houssayanthus Hunz., 2 spp., Lophostigma Radlk., 1 sp., Paullinia L., 3 spp., Serjania Miller, 16 spp., and Urvillea Kunth, 4 spp.); subtribe Tlúnouúnae (Thinouia Triana & Planchon, 1 sp.). All of them grow in Argentina, except L. plumosum Radlk. and H. monogynus (Schdl.) Ferrucci, collected in Bolivia and Paraguay respectively.Four pollen types have been recognized: type A - isopolar, tricolporate, subspheroidal to oblate-spheroidal grains in Thinouia; type B - isopolar or subisopolar, trisyncolporate, heterocolpate, dicolpodiorate, monocolpate, prolate or prolate-spheroidal grains in Lophostigma; type C - heteropolar, hemitrisyncolporate, peroblate or oblate grains are shared by Serjania, Houssayanthus, Cardiospermum and Urvillea, (in these genera tbree groups are recognized based on details of structure and sculpture) and type D - isopolar or subisopolar triporate, oblate or peroblate grains in Paullinia.The probable evolutionary trends of pollen morphology cbaracters are discussed. Based on shape and aperture types of the grains, a tentative phylogenetic line of the tribe is presented