Articles written in Proceedings – Plant Sciences
Volume 87 Issue 11 November 1978 pp 325-333
Evolution was in the beginning applied to the species. When genetics established the independent inheritance of characters, evolution also began to be analysed in terms of characters or organs, each considered independent in its evolutionary trend. Subsequently, however, this rule of independence began to be violated in the attempts to determine evolutionary status by correlation. Furthermore, the circumscription of an organ for evolutionary correlation is equivocal. With regard to the vegetative and floral morphology of the angiosperms, the concepts of old formal morphology in terms of fundamental organs were more definite and evolution has not been able to offer anything better. Many of the concepts of formal morphology have
The principles laid down by Carlquist, in what he has proposed to be a function oriented approach to angiosperm morphology, appear to be based on undue assumptions with a mixing up of homology and evolution. The decline of evolution as the directive force behind plant morphology necessitates new approaches that could impart dynamism to this basic discipline of botanical study.
Volume 95 Issue 6 December 1985 pp 429-436
The palmately compound leaf of
Volume 96 Issue 6 December 1986 pp 475-486
Leaf initiation is hypodermal. The primordium quickly acquires the configuration of a 5 layered laminar plate meristem and its base extends around the shoot apex as the sheath. Following this, apical growth ceases in the primordium. Its apex becomes a hood like lamina wing and the sheath develops a median adaxial meristem which leads to its thickening. The lamina wing expends and becomes plicately folded at right angles to its surface. Each fold becomes a leaflet by the elongation of the abaxial edges and suppression of the adaxial edges of the folds. Early abortion of the lamina wing results in a scale leaf which comprises the sheath portion alone.
An adult leaf has 300-400 veins which run independently from the corm to the leaflets through the petiole. The dorsal median strand develops first and goes to the midrib of the median leaflet. Subsequent strands arise laterally on either side of this in a series of tangential rows. Those of the first row bifurcate at the tip of the petiole to enter two neighbouring leaflets. The strands run parallel in the leaflet midrib and diverge at different levels into the lamina as lateral veins.
Volume 98 Issue 4 August 1988 pp 251-255
In the anther primordium of