Volume 65, Issue 4
April 1967, pages 135-173
pp 135-141 April 1967
Some teratological aberrations in the soral structure and development ofScolopendrium vulgare Smith. have been described in detail. These abnormalities have been discussed mainly from causal point of view. Abnormalities like close formation of paired sori, formation of shield-shaped indusium, development of barren or arrested sori in abnormal positions and effects of displacement of receptacular vascular supply have been illustrated. They have been attributed to several factors,viz., reduced leaf lamina, congenital growth of the indusia of two back-to-back closely lying sori, poor illumination and decline in the supply of nutrients respectively. The role of solar radiation in the production of biochemical substances and that of the latter on the soral development have been hinted at. It has been conclusively pointed out that these abnormalities need careful study and appreciation from the morphogenetical or causal viewpoint.
pp 142-152 April 1967
The vegetative anatomy of one South Indian species ofSagittaria [S. guayanensis ssp.lappula (D.Don) Bogin] which has not been studied before has been investigated. The studies pertain not only to the anatomy of the adult form but to that of the juvenile form. It is shown that this taxon differs from other related species of the genus in 12 important characters and thus seems to be distinct.
pp 153-160 April 1967
Nodal anatomy of sixteen species has been worked out. Of these, fifteen are three-traced trilacunar, the three traces uniting in the nodal cortex to form a single petiolar strand of various types. In only one species the structure has been found to be one-traced unilacunar. These results are in disagreement with the earlier report of an exclusively unilacunar condition. The trilacunar node has been considered to be primitive and the unilacunar derived from it.
pp 161-164 April 1967
Tylophora subramanii Henry, sp. nov. (Asclepiadaceae) collected from Tirunelveli district, Madras State, is described with illustrations.
pp 165-166 April 1967
Colchicine-cum-irradiated seedlings of maize showed considerable increase in leaf-hair length and a definite correlation between the dosage and hair length was realised. The radiation stimulated hair length is attributed to a greater degree of cell expansion.
pp 167-173 April 1967
Using the data given by Leake (1960) and following the Hey’s procedure (1956), the optical parameters of cordierites are expressed in terms of five principal components. The residuals have been calculated and the significance of these results is briefly discussed.