Volume 24, Issue 5
November 1946, pages 207-245
pp 207-224 November 1946
The floral members arise as protuberances of the rachilla:—-the order of succession being—glumes, lemma, palea, stamens, lodicules and gynœcium.
The gynœcium consists of a monocarpellary ovary with a single terminal ovule and two styles.
There are two integuments, inner forming the micropyle and the outer incomplete; both are 2-layered. InPanicum both the integuments form the micropyle.
The archesporium comprises of a solitary, hypodermal cell, no parietal cells being formed.Setaria shows a peculiar hypertrophy of one of the epidermal apical cells.
Tetrad formation is linear; lowest megaspore forms the embryo-sac mother cell.
The mature embryo-sac is 8-nucleate and of the normal type in all the plants.
The egg-apparatus is typical, the egg cell is slightly larger than the synergids and elongates considerably after fertilization. It has a heavy deposit of starch grains. The polar nuclei are large and lie in close proximity to the egg where they fuse.
The antipodals are well developed—the forms varying in the four plants. InEleusine none of the 3 cells divide but become large and prominent; inPanicum they form a tissue of 6 uninucleate cells; inSetaria there are 3–5, 1–4 nucleate cells and inPennisetum there are 6 multinucleate cells.Eleusine has the passive type and the rest the aggressive type of antipodals.
Fertilization is porogamous and the sperm cell is spherical.
The primary endosperm nucleus undergoes free nuclear division without rest–wall formation commencing near the embryo first.
The zygote divides to form a three-celled proembryo, the two terminal ones of which divide and redivide to form the embryo and the basal one the suspensor. The embryo consists of a terminal cotyledon, the coleoptile enclosing the laterally situated stem apex and the coleorhiza enclosing the radicle with its root-cap.
Of the two integuments, the outer one disintegrates, the inner forming the seed coat; deposits occur in the surviving coat ofEleusine seed. Pericarp development same as recorded for wheat.
pp 225-242 November 1946
pp 243-245 November 1946
Small pinkish-white fungal areas ofColletotrichmu gloeosporioides Penz. were observed on trunks and main branches of orange plants. In certain localities mosambi plants were also infected.
Water shoots and young twigs were always found free from the infection.
During summer months the mycelium of the fungus survives in the form of pink coloured stroma in small cracks in the bark of orange or mosambi trees and thus tides over the unfavourable atmosphere condition.
Mycelium on the host persists as inter- and intra-cellula parasite in one or two layers of the cortical tissue.
The disease could be induced artificially.
Measurements of the spores, setæ and hyphæ are given.
The isolated strain ofC. gloeosporioides corresponds to strain A, No. 316 of Chaudhari and practically falls within the second group of Baker, Crowdy and MeKee.
Acervuli of the pathogen has been observed on dead wood also.