Variation in Rhododendron arboreum Sm. complex (Ericaceae): insights from exomorphology, leaf anatomy and pollen morphology (original) (raw)
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Foliar micro-morphological traits in some members of Ericaceae from Darjeeling Himalaya
Ten species of Ericaceae from Darjeeling Himalaya [Gaultheria nummularioides D. Don, Gaultheria fragrantissima Wall., Pieris formosa (Wall.) D. Don, Lyonia ovalifolia (Wall.) Drude, Rhododendron arboreum Sm., Rhododendron arboreum subsp. cinnamomeum (Wall. ex G.Don) Lindl., Rhododendron barbatum Wall. ex G.Don, Rhododendron griffithianum Wight, Rhododendron lepidotum Wall. ex G.Don and Rhododendron dalhousiae Hook. f.] were studied with respect to foliar morphometric characters. The quantitative data revealed some wide variation in leaf lamina characters while some tend to be closely related. Estimation of vein-islet number have also been made. The taxonomic relationships among the taxa have been depicted through cluster analysis and dendrogram.
Pollen morphology of Erica L. and related genera and its taxonomic significance.pdf
Pollen morphology of a total of 25 species of Erica (23 species) and its closely related genera Calluna (monotypic) and Daboecia (monotypic) was examined by means of light and scanning electron microscopy (SEM), or SEM alone. The pollen tetrads of E. multiflora and E. trimera ssp. keniensis, and monads of E. barbigeroides and E. recurvifolia, were examined with transmission electron microscopy to study the exine stratification. The quantitative features of Erica pollen have varied widely. However, the exine sculpture of Erica pollen is often characterised by the presence of numerous minute granules as secondary sculpture. Calluna pollen is characterised by irregular tetrads and perforated septum, and the Daboecia pollen tetrads by larger values of the D/d, P/E and 2f/D ratios. The P/E ratio and exine architecture showed distinct differences between Erica monads and tetrads. Among the Erica species having pollen tetrads, two distinctly different palynomorphological groups could be identified based on the 2f/D ratio. Two distinct groups could also be differentiated on the basis of the L/P ratio within the Erica species producing monads. Palynological characters, therefore, might be featured as a useful tool to clarify infrageneric classification system for the large genus Erica.
Bangladesh Journal of Plant Taxonomy, 2009
Pollen morphology of two subfamilies of Ericaceae, Cassiopoideae and Harrimanelloideae, was studied using light microscopy (LM), scanning electron microscopy (SEM), and also, for selected species, transmission electron microscopy (TEM). The systematic significance of new palynological data is discussed in the light of the recent classification of Ericaceae. The Cassiopoideae are stenopalynous; the four 3aperturate grains are united in compact minute tetrads with striate apoclopial exine sculpture. Infra-and inter-specific variations have been observed in some palynological features of Cassiope, this might be due to geographical distribution. The Harrimanelloideae pollen grain is characterized by minute tetrahedral tetrads with coarsely rugulate to psilate apoclopial exine sculpture and perforated septum. Pollen morphology supports the subfamilial status of Cassiopoideae and Harrimanelloideae, and the close relationship between the members of subfamily Harrimanelloideae and Vaccinioideae. The secondary sculpture on the exine surface might be a synapomorphic palynological character state for Harrimanelloideae + Styphelioideae + Vaccinioideae clade.
A Study on Turkish Rhododendron L. (Ericaceae)
Turkish Journal of Agriculture and Forestry, 2001
Some of the Turkish Rhododendron L. taxa need wood anatomical and palynological studies for their certain determination together with morphological studies. Therefore, some of them were studied and a revised list of them is given. New distribution areas of a newly recorded endemic variety of Rhododendron ponticum L. (Rhododendron ponticum L. subsp. ponticum var. heterophyllum Anflin) were determined: A7 Trabzon: Maçka, A8 Rize: Çaml›hemflin and A8 Artvin: Murgul, in addition to the already known A8 Trabzon: Of region. Morphological, wood anatomical and palynological features of very rare white-flowered specimens of Rhododendron ponticum L. were compared to the main taxa of Rhododendron ponticum L., with purplish-pink flowers, and Rhododendron x sochadzeae Charadze & Davlianidze, which has nearly the same colored flowers and a hairy ovary. The specimens of Rhododendron ponticum L.with white flower and a naked ovary, collected from Turkey, were studied for the first time from anatomical and palynological points of view and were determined to be a natural form of Rhododendron ponticum L. (Rhododendron ponticum L. subsp. ponticum forma album (Sweet.) Zab.).
Biodiversity profile The genus Rhododendron in north-east India
2011
The genus Rhododendron belongs to the family Ericaceae and was described by Carl Linnaeus in 1737 in Genera Plantarum. Joseph Hooker’s visit to Sikkim Himalaya between 1848 and 1850 unfold the rhododendron world of this area. Within the brief span that he travelled in Sikkim, he gathered and described 34 new species and details of 43 species including varieties from the Indian region in his monograph entitled ‘Rhododendron of Sikkim Himalaya’. Since then many workers had added to the list, and currently about 121 taxa have been recorded from India, out of which 117 (98%) taxa are distributed in north-east India. The paper presents the distribution of the genus Rhododendron in north-east India and world based on literature, field studies and examination of herbarium specimens. It also discussed the status of the genus in natural habitat in recent years and the need for conservation. Key-words: Rhododendron, distribution, north-east India
Pollen morphology of Rhododendron L. and related genera and its taxonomic significance
Bangladesh Journal of Plant Taxonomy, 2013
Pollen grains of 40 taxa of Rhododendron L. and its closely related genera, Therorhodion L. and Menziesia Sm., were examined by means of light microscopy and scanning electron microscopy (SEM), or SEM alone. Pollen tetrads of R. japonicum, R. schlippenbachii, R. tsusiophyllum and M. pentandra were examined also with transmission electron microscopy. In all the genera studied, 3-colporate, oblate to suboblate pollen grains are arranged in tetrahedral tetrads. The apocolpial pollen wall is composed of the exine -well developed tectum, columellae, foot layer and endexine, and the intine. On the contrary, the septal exine is composed of fragmentary tectum, and the two foot layers of adjacent grains are sometimes connected by columellae and endexine. Among different infrageneric taxa only the subsect. Ledum (sect. & subgen. Rhododendron) was characterized by small sized pollen tetrads, higher 2f/D value and rugulate exine sculpture. The pollen morphological characteristics overlapped each other in all other taxa. Thus palynological features showed little usefulness in the infrageneric classification of Rhododendron, however, they gave additional support to the individual generic status of Menziesia and Tsusiophyllum, and the sister relationship between Rhododendron and Therorhodion.
On the typification and nomenclature of Rhododendron ×intermedium (Ericaceae)
Phytotaxa, 2017
We discuss the typification and nomenclature of the name Rhododendron ×intermedium (Ericaceae). As the name R. ×intermedium Wenderoth is invalid, the earliest legitimate name for R. ferrugineum × R. hirsutum hybrid is the name published by Tausch. We designate one collection from PRC as the lectotype and two other specimens from PRC are considered to be a part of the original material. A list of R. ×intermedium synonyms is provided and two specimens from IBF are designated as the neotypes of two heterotypic synonyms, namely R. ×halense and R. ×hirsutiformum.