Pollen morphology of the three subgenera ofAlnus

Combined LM and SEM study of the middle Miocene (Sarmatian) palynoflora from the Lavanttal Basin, Austria: part IV. Magnoliophyta 2 – Fagales to Rosales

“…Hence, the molecular estimates only give an estimate for crown group radiation within this subgenus, but not the genus itself, which would resolve the potential conflict between the finding of Alnus clarnoensis (Liu et al 2014) and the c. 15 Ma younger crown group divergence estimates (Grimm & Renner 2013). In addition, all highlighted diagnostic characters are also found in at least one of the three species of subgenus Chletropsis sensu stricto (Leopold et al 2012;Liu et al 2014, table 2), which is resolved as the sister clade of subgenus Alnus in available molecular phylogenies (Navarro et al 2003;Chen & Li 2004) and morphologically overlapping with the latter.…”

“…-Pollen morphology (LM, SEM) and partly the ultrastructure (SEM) of Betulaceae has been described in detail by Chen (1991) and Blackmore et al (2003). The pollen morphology (LM and SEM) of all subgenera of Alnus, including pollen from most of the extant Alnus species has been documented by Huang (1972), Lieux (1980), Chen (1991), Jones et al (1995), Wang et al (1995), Fritz and Allesch (1999), Perveen and Qaiser (1999), Blackmore et al (2003), Beug (2004), Fujiki and Ozawa (2007), Li et al (2011a), May (2011), Miyoshi et al (2011), Leopold et al (2012), May and Lacourse (2012) and Liu et al (2014). Fossil pollen showing LM-based morphological affinities to pollen of modern Alnus have commonly been assigned to the pollen form-genera Alnipollenites (e.g.…”

“…The data set did include A. nepalensis D.Don, a species originally assigned to the subgenus Clethropsis but nesting within the subgenus Alnus clade according to molecular data (e.g. Chen & Li 2004;Grimm & Renner 2013), a position further supported by overall pollen features (Leopold et al 2012). Hence, the molecular estimates only give an estimate for crown group radiation within this subgenus, but not the genus itself, which would resolve the potential conflict between the finding of Alnus clarnoensis (Liu et al 2014) and the c. 15 Ma younger crown group divergence estimates (Grimm & Renner 2013).…”

“…Thomson & Pflug 1953;Stuchlik et al 2009). Assignment of individual fossils to one of the (two or) three modern subgenera Alnus, Clethropsis, Alnobetula (Furlow 1979;Leopold et al 2012) is, however, difficult.…”

Pollen Morphology of A. glutinosa (L.) Gaertner subsp. glutinosa (Betulaceae)

“…These findings are consistent with our study except for percentage of pollen grains based on pore number. Leopod et al (2012) determined that the morphology of Alnus pollen is unique within the Betulaceae. Ornamentation shows similar characteristics in both Betula and Alnus pollen, such that the sculpture is psilate in surface view based on LM, scabrate under scanning electron microscope (SEM).…”