Volume 15, Issue 4
April 1942, pages 167-231
pp 167-171 April 1942
A leaf spot disease caused byPhyllosticta zingiberi is common in Godavari and Malabar districts. Spots with whitish centres develop on the leaves and in these pycnidia of the fungus are formed. Wound inoculations were successful on ginger and turmeric. Soon after isolation, cultures on ginger leaves are able to infect unwounded ginger leaves.
This fungus does not agree with the description ofConiothyrium zingiberi. The spores are smaller and never coloured. Hence it is given the name ofPhyllosticta zingiberi.
pp 172-177 April 1942
The observations recorded in the foregoing pages thus warrant the following general conclusion with regard to the origin of the amphiphloic siphonostele inSelaginella:
The origin of the siphonostele inSelaginella is correlated with the polystelic condition and the amphiphloic siphonostele originated as a result of a fusion of a number of separate steles. The polystelic condition probably originated in response to the necessity of increasing the amount of conducting and mechanical tissues in the absence of provision for secondary growth. The pith is extrastelar in origin and the presence of internal phloem and internal endodermis is directly due to the origin of the siphonostele from the polystelic condition.
pp 178-180 April 1942
pp 181-185 April 1942
pp 186-193 April 1942
Phragmotelium mysorensis is a new species of rust attacking the leaves ofRubus lasiocarpus Smith.
All the four spore-forms,viz., 0, I, II and III occur on the same host.
Pycnia are sub-cuticular, and aecia are of the cæoma type with paraphyses. Development of cæoma and the initiation of the dicaryon phase has been studied.
Uredia are hypophyllous, pulverulent, covered with incurved paraphyses.
Telia are hypophyllous, associated with the uredia and covered with paraphyses. Teliospores are five to six septate. Teliospores are smooth, thin-walled, with two indistinct germ pores in each cell. Pedicels are hyaline and do not swell in water. Teliospores germinate soon after maturity, and form sporidia which are uni-nucleate.
Sporidial infections indicate that the rust is autoecious.
pp 194-201 April 1942
The hypodermal archesporial cell directly functions as the mega-spore mother cell.
The mode of development of the embryo-sac conforms to theAllium type. Sometimes only 6-nucleate embryo-sacs are seen due to a reduction of the number of divisions at the chalazal end.
The pollen tube enters through the micropyle. Double fertilization has been observed.
A long suspensor is formed during the development of the embryo. The terminal cell forms a filamentous proembryo which gives rise to the embryo.
Some of the suspensor cells at the micropylar end elongate and enlarge to enormous proportions. They are however not haustorial and degenerate in later stages.
Cleavage polyembryony is reported and its mode of origin and deve-lopment traced. The plural embryos are monozygotic.
pp 202-205 April 1942
pp 206-215 April 1942
This is the third contribution in the series“Indian Water Moulds”. Two species of Achlya, viz., Achlya oblongata and A. androcomposita nov. sp. and one species of Pythiogeton, viz., P. sterilis nov. sp., have been described.
pp 216-224 April 1942
In this fourth paper of the series on Indian Water Moulds, the authors have recorded and described three water moulds not so far reported from this country of which, one is a new species. These are Protoachlya paradoxa, Pythiopsis intermedia nov. sp. and Saprolegnia rhætica Maurizio.
pp 225-230 April 1942
A new genus of Saprolegniaceæ—Hamidia has been isolated, grown in culture, and described; and a new species Hamidia indica established. The Latin diagnosis in both cases has been given.
pp 231-231 April 1942 Erratum