Pollen morphology of the Embothrieae (Proteaceae) II. Embothriinae (Embothrium, Oreocallis, Telopea)

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Abstract
This is the second of two papers dealing with pollen morphology and evolution within the tribe Embothrieae. The present paper examines pollen of the subtribe Embothriinae, Embothrium (1 sp.), Oreocallis (6 spp.), Telopea (4 spp.)) in the light microscope and scanning and transmission electron microscopes. Pollen is large-sized, oblate to suboblate to oblate-spheroidal, foveolate to microreticulate to spinulate with a predominantly granular exine and simple aperture morphology. The Embothriinae are palynologically heterogeneous with both Oreocallis and Telopea each exhibiting two distinct pollen types. Pollen of New World Oreocallis (O. grandiflora, O. mucronala) and the Old World O. pinnata are closer to the Old World Telopea (excluding T. speciosissima) than to other Old World Oreocallis (O. sp. nov. O. brachycarpa, O. wickhamii). Within this complex, O. pinnata occupies an intermediate position between Oreocallis and Telopea. Despite the uniformly biporate condition in Embothrium, other pollen characters support its inclusion in Embothriinae with close ties to Oreocallis. Analysis of pollen trends within the tribe reveal: (1) an increase in pollen size; (2) a trend towards more spheroidal pollen; (3) the independent developments of biporate pollen in Embothrium, Oreocallis and Lomatia; (4) independent developments of recticulate and spinulate sculpturing from a tectate-perforate exine; (5) loss of columellae; and 6) independent developments of complex modified postvestibulate and simple thickened-lamellate aperture morphologies.

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