• Volume 96, Issue 3

      August 1986,   pages  159-246

    • Structure and function of the Central Himalayan oak forests

      S P Singh J S Singh

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      Oak (Quercus spp.) forests represent the climax evergreen vegetation between 1000–3600 m in the Central Himalaya. Shrub layer is well developed in these forests and phanerophytes prevail (50–60%). Though one oak species mixes frequently with other oak species, or conifers, the single-species dominance is quite common. All the oak forests are vulnerable to fire. They support a great variety of wildlife. Coppicing subsequent to cutting is well developed in all oak species and helps them in regeneration. However, because of severe biotic stress oaks are failing to regenerate in forest stands. The forest biomass ranges between 294–787 t ha−1 and the net primary productivity generally between 16–21 t ha−1 yr−1. Oak forests store a large proportion of their nutrients in biomass component. Leaves are nutrient-rich and decompose rapidly. Evergreen woody species with concentrated summer leaf drop prevail in oak forests. The seasonality of the ecosystem activities seem to be influenced by the monsoon pattern of rainfall. Though the recovery is rapid after the forest destruction, because of continuous and severe biotic stress, oaks are being replaced with other communities.

    • Dwiroopa, a new genus of the Coelomycetes

      C V Subramanian J Muthumary

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      Dwiroopa, anamorph gen. nov. andDwiroopa ramya anamorph sp. nov. are proposed to accommodate a eustromatic fungus collected on dead twigs from forests of Western Ghats in Agumbe, Karnataka State. The fungus produces stromata within which two types, the α- and β-conidia are produced. Both are solitary, one-celled, gangliar and brown coloured but the α-conidia are clearly larger, darker and have very characteristic striations on the surface, absent in the β-conidia. In addition, small, one-celled, allantoid, phialoconidia may be produced in some of the conidiomata. The present fungus is compared with the closely allied Coelomycete genusHarknessia Cooke.

    • Dwiroopella, a new genus of the Coelomycetes

      C V Subramanian J Muthumary

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      Dwiroopella, gen. nov. typified byDwiroopella sundara sp. nov. is proposed to accommodate a Coelomycete collected from Karnataka. This is an interesting fungus in which the conidioma is eustromatic, solitary, ostiolate, rostrate, clypeate, partly immersed in the substrate and partly erumpent. Each conidioma produces within it two types of conidium, phialoconidia from simple phialides which proliferate percurrently and gangliar conidia from annellated conidiogenous cells. Both types of conidia are brown and typically two-celled, the phialoconidia may become 3–4-celled.

    • Azide mutagenesis in rice

      D Rama Mohana Rao T V V Seetharami Reddi

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      Seeds of rice cultivars viz Jaya, IET 5656 and Fujiminori presoaked for 24 h were treated with 0·001, 0·002, 0·004 and 0·005 molar concentrations of sodium azide at pH 3 for 4 h with a view to investigate its mutagenic action in rice. The percentage of germination, survival, seedling height and leaf number decreased in the treated population with a few exceptions. Cytologically abnormal plants were not detected in any of the treated population. Plant height, panicle branches, seed set and panicle grain weight decreased in the azide treated population whereas tiller number increased in Jaya and Fujiminori cultivars. The frequency of chlorophyll mutants induced was more in Jaya less in IET 5656 and the least in Fujiminori 0·005 molar concentration was found to be the most effective for inducing chlorophyll mutations in IET 5656 and Fujiminori. The same concentration induced more morphological mutants in all the 3 cultivars. Morphological and physiological mutants isolated include the tall, semidwarf, dwarf, early and late flowering mutants, protein rich mutants, grain shape mutants and many others. Varietal differences are indicated in the induction of seedling injury and of chlorophyll and morphological mutants produced.

    • Scanning electron microscopic studies on the pollen of some Clusiaceae

      Y N Seetharam J K Maheshwari

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      Ten species of Clusiaceae are studied with scanning electron microscope. Characters like scattered tectal perforations inAllanblackia andRheedia, granulate apertural membrane of theHarungana, Psorospermum andVismia, spinules borne on stilts inGarcinia balica and on ascending ridge like elements inGarcinia travancorica are brought to light.

    • Macrolichen taxa of Teloschistaceae from India

      D D Awasthi

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      Morphotaxonomic description of one species ofTeloschistes and 5 species ofXanthoria occurring in India are given. A new combinationXanthoria fallax var.subsorediosa (Räs.) Awas. is also made.

    • The floral anatomy ofGloriosa superba L. andTricyrtis pilosa Wall. (Liliaceae)

      N P Vaikos R M Pai

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      In both the taxa, the tepals are 3-traced and the extrorse stamens are one-traced. The placentation is parietal. The bases of the 6 tepals (Gloriosa) or the outer tepals (Tricyrtis) are nectariferous. These appear like ‘pouches’ or ‘sacs’. The increased branching of the traces at the base of the outer tepals inTricyrtis and of both the whorls inGloriosa is related with the development of the nectaries. The study reveals that both genera are rather close and are more at home together in a taxonomic entity.

    • Taxonomic status of theSolanum nigrum complex found in India

      A Ganapathi G R Rao

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      An attempt has been made, with the help of modern taxonomic treatments, to determine the correct taxonomic status of theSolanum nigrum L. complex in India. On the basis of comparative morphological and cytological studies, it is concluded that the diploids, tetraploids and hexaploids are in fact,Solanum americanum Mill. var.patulum; Solanum villosum Mill. subsp.miniatum (Bernh. ex willd.) Edmonds, andSolanum nigrum L. subsp.nigrum, respectively.


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