Volume 79, Issue 2
February 1974, pages 53-102
pp 53-58 February 1974
pp 59-67 February 1974
pp 68-79 February 1974
Morphology of seven species of exindusiate thelypteroid ferns belonging to three genera,viz., Phegopteris, Pseudophegopteris andMacrothelypteris is described. The paleae are gland-tipped except inM. ornata, P. hexagonoptera andP. decursive-pinnata where it is non-glandular. The dictyostele consists of 2–4 vascular strands. The lamina bears reduced scales (sometimes branched) mixed with the hairs, both acicular and glandular. The sori are usually exindusiate; inP. decursive-pinnata the indusium is modified into tufts of fasciculated hairs whereas inM. torresiana a small fugaceous indusium is present. The trichomes are borne on the capsule wall only. Spores are of bilateral type and usually perinate. The exine is smooth or verrucate; inP. aurita andP. pyrrhorhachis it bears narrow ridge-like irregular reticulations. InM. ornata, the exine as well as perine are spinulose. It is concluded that the exindusiate species are quite distinct from the other members of the family and constitutes a natural group.
pp 80-90 February 1974
Epidermal morphology of 22 species, including 2 varieties ofAdiantum is described. The upper and lower epidermal cells are either rectangular or irregular in shape and generally arranged parallel to the veins. The anticlinal walls of the intercostal cells are usually deeply sinuous. The costal cells are narrower, much elongated with sinuous walls except inA. cuneatum, A. fergusoni andA. formosum in which the cells are straight walled. Stomata are anomocytic type, the largest ones occur inA. macrophyllum, the smallest inA. peruvianum. Uniseriate, 2–4 celled, thick-walled acicular hairs occur in 5 species ofAdiantum. Characteristic “Spicular Cells” have been obsreved inA. macrophyllum.
pp 91-95 February 1974
Organisation of the shoot apex and the development of axillary bud and leaf primordium have been investigated inCrotalaria retusa. The shoot apex ranges from slightly elevated to deeply convex in its shape. Tunica is single layered while the corpus is of 3–5 layers. Anticlinal division is the rule in the tunica cells whereas the corpus cells undergo divisions in all the planes. Three zones,viz., central, flanking and pithrib meristem zone, are present though not very distinctly. Leaf primordium is initiated only by corpus, while the tunica remains as the epidermis. Axillary bud is deeply stained in its early ontogeny and arises from the detached meristem as evidenced by the deep seated nature and the presence of a distinct shell zone on its adaxial side.
pp 96-102 February 1974
Time course of laboratory acclimation to cold (20° C) and warm (35° C) temperatures is followed. It is found that the rate as well as degree of thermal acclimation of the rate of oxygen consumption both in the ground lizard,Sitana ponticeriana, and the garden lizard,Calotes nemoricola were dependent on the season and temperature gradient. It was found that acclimation to cold and warm temperatures does not occur in the laboratory.