Abstract
Pollen morphology of 13 taxa belonging to 5 genera of the tribe Phyllodoceae (Ericaceae) was examined by means of light and scanning electron microscopy (LM and SEM, respectively), or SEM alone. In Phyllodoceae, 3-colpor(oid)ate, minute to medium, oblate pollen grains are united usually in tetrahedral tetrads. Pollen tetrads are generally characterized by the presence of viscin threads except Elliottia pyroliflora, Epigaea asiatica and Phyllodoce caerulea. The absence of viscin threads might indicate to a secondary loss, since these are present at least in some species within all the genera of Phyllodoceae. The pollen morphological data confirm the infra- and inter-generic relationships as identified by molecular phylogeny of Phyllodoceae and/or vice-versa. Although various palynological characters were found to be taxonomically important at different taxonomic levels, the apocolpial exine sculpture is emerged as one of the most important palynological features of systematic importance. The rugulate apocolpial exine with striate secondary sculpture and a reduced colpus might be apomorphic palynological character states for this tribe and Ericaceae as well. Hitherto, it is the first SEM study of Rhodothamnus pollen.DOI: http://dx.doi.org/10.3329/bjpt.v21i2.21351Bangladesh J. Plant Taxon. 21(2): 129-137, 2014 (December)
Highlights
The Phyllodoceae Drude is one of the most morphologically heterogeneous group that apparently has no morphological synapomorphy (Kron, 1997)
The aims of the present study are to provide the palynological data of the genera of Phyllodoceae in addition to Kalmia, by using both Light microscopy (LM) and scanning electron microscopy (SEM), and to discuss its systematic significance in light of the recent molecular phylogenetic relationship of this tribe
Pollen morphology of the genus Kalmia has been studied in details (Sarwar and Takahashi, 2012) and the data has been included in discussion
Summary
The Phyllodoceae Drude is one of the most morphologically heterogeneous group that apparently has no morphological synapomorphy (Kron, 1997). The inclusion of Epigaea in the tribe Phyllodoceae might increase the morphological heterogeneity of this group and the monophyly of this group is not well supported by morphology. Some species have pollen dispersed by curved stamens that spring out from the flower centre, explosively. Many species in this group are poisonous, e.g., Kalmia, both to livestock and people. At least one taxon from all currently recognized tribes within the Ericoideae have at some point been classified within the Phyllodoceae, illustrating the difficulty in determining relationships of these taxa based on morphological or anatomical evidence alone (Gillespie and Kron, 2013)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
