Volume 83, Issue 4
April 1976, pages 133-176
pp 133-138 April 1976
The mycoflora colonizing the litter ofAtlantia monophylla Corr. andGymnosporia emarginata Laws. was analysed at monthly intervals during a one-year period. The fungi were grouped as ‘dominant’, ‘common’, ‘frequent’, ‘occasional’ and ‘rare’ depending on their percentage frequency. Only a few fungi appeared to be ‘dominant’ on each plant species and nearly half the number of species recorded occurred sporadically. Each plant had its own characteristic ‘dominant’ mycoflora which included mostly host specific forms. Many species were found to be common to both plant species, but the frequency and percentage occurrence of these species was different on both litter types.
pp 139-142 April 1976
Studies on the C-heterochromatin during the meiosis in the Indian grasshopperPoekilocerus pictus has been carried out using the BSG technique presumably for the first time. It is shown that the genome of this grasshopper is endowed with large amounts of repetitive DNA in the centromeric, interstitial and telomeric regions. This Acridid under study differs in having distinct centromeric, interstitial and telomeric blocks in majority of the chromosomes from the British AcrididMyrmeleotettix maculatus which has interstitial bands only in the X-chromosome and the B-chromosome but not in the autosomes.
pp 143-146 April 1976
Stomatal ontogeny and distribution in the Indian fernHemionites arifolia has been studied for the first time. The stomata conform to the mesoperigenousPlagiogyria type; a few stomata are diacytic.
pp 147-149 April 1976
Marsdenia raziana which represents a new species of Asclepiadaceae, collected around Yelnir ghats forests (W. ghats), Samse, Chikmagalur District, has been described and illustrated.
pp 150-159 April 1976
Electron probe microanalyses of 38 muscovites from Warramunga rocks, “porphyroidal” rocks and from magnetite rocks of lode structures of Tennant Creek field were carried out. Recrystallisation of muscovite, progressive in Warramunga rocks and retrogressive in “porphyroidal” rocks was contemporaneous and took place under lower green schist facies conditions of metamorphism during regional deformation. Muscovite in the magnetite lode structures and the country rock had formed ahead of the sulphide mineralisation on the Warramunga rocks subsequent to their regional metamorphism and was due to metasomatic alteration on the wall rocks.
The analysed muscovites conform to phengite mica but some of them have Si in excess of the stipulated limit of 3·5 units per half unit cell. The analysed phengites show a shift in the layer charge from tetrahedral to octahedral layer conforming to trisilicictetrasilicic series. The (Si +R2+) and (AlVI + AlIV) show positive correlation. The author advocates that the term phengite be retained to describe all the intermediate members of the potassium dioctahedral micas including those having Si in excess on the stipulated limit.
pp 160-165 April 1976
This paper presents the aerodynamic parameters, the structure and functions of the flight surface together with its radiographic information in the case ofC. marginatus.
pp 166-176 April 1976
Cytohistologically the shoot apex ofRicinus communis is distinguished into five zones: (i) Tunica, (ii) Corpus, (iii) Flank meristem, (iv) Rib meristem, and (v) Cambium-like zone. The cells of the cambium-like zone are radially elongated and stretched across the apex from the base of the leaf. This zone is formed during the early part of the plastochron. The differentiation of this zone begins in the centre of the apex and proceeds outwards. It becomes fully developed by mid-phase. This zone is responsible for the differentiation of the node and elongation of the stem. Leaf initiation takes place in the second tunica layer and the leaf primordium increases in height by a group of subapical initials. Apical growth of the primordium ceases when it is about 120 microns high. The cells of the middle layers are derived by the periclinal divisions of both adaxial and abaxial hypodermal layers.