Conospermeae (Proteoideae) pollen morphology and its phylogenetic implications

Pollen morphological trends in modern taxa, the fossil pollen record, and c omparative palynology can be useful aids to taxonomy and indicators of evol utionary lineages. In Conospermeae, each species and genus has a distinct p ollen morphology character set, although individual characters may not be t axon-specific. Aperture form in Conospermeae may be consistent or diverse w ithin a genus, and has limited or no taxonomic value above the generic leve l; whereas with the exception of Beauprea Brongn. & Gris., sculptural type is consistent within a genus and often within subtribes. In the light of ge neric characters, a review of fossil pollen affiliates of Conospermeae indi cates that the fossil record of Stirlingia Endl. and Symphionema R.Br. is n ot as extensive as previously thought. Conospermeae pollen morphology thus far investigated, together with the fossil record, suggests the tribe is no t monophyletic but includes several evolutionary lineages. Synaphea R.Br, a nd Conospermum Sm. (Conosperminae), together with Stirlingia (Stirlingiinae ), may have close ties with Persoonioideae. Isopogon R.Br. ex Knight and Pe trophile R.Br. (Petrophilinae) can be sculpturally aligned with Symphionema (Cenarrheninae) and several Proteeae genera, and to a lesser degree, Agast achys R.Br. (Cenarrheninae) with Aulax (Proteeae). Of the monotypic genera, pollen of Beaupreopsis Virot and Cenarrhenes Labill. are alike, and that o f Dilobeia Thouars. has similarities to these genera but is also not unlike pollen of Bellendena R.Br. (Bellendenoideae). Beauprea pollen is morpholog ically unique among the Proteaceae in having colpoid apertures and diverse sculptural types. Pollen of Beauprea species so far investigated appear to more closely resemble pollen of Persoonioideae than that of other Conosperm eae genera. The fossil record, however, indicates that Beauprea pollen has sculptural analogues in all Proteaceae subfamilies, suggesting that its rel ationship to the rest of the family is complex. The fossil pollen record an d patterns in modern pollen morphology can confirm or suggest taxonomic and phyletic relationships, but for firmer resolution are best used in conjunc tion with other lines of evidence.