MISCELLANEOUS NOTES. 616 



No. XXXII.— SOME DISEASES ON TREES IN MYSORE CAUSED 

 BY A SPECIES OF FHYTOriLTHOBA. 



A Preliminary Note. 



While investigating the disease on the areca-nut caused by Phytophthom , 

 under Dr. Leslie C. Coleman, I have come across (1) a disease of figs 

 {Ficus carica) causing a soft rot, and (2) a disease on citron {Citrus medico), 

 Vern. Can. Madala-Hannu and (3) Canker in the cortex of the Para rubber 

 {Hevea brasiliensis). The first of these Avas met with in Bangalore. The 

 second in the Bababudans and the last in the coffee areas of Koppa. The 

 third one seems to be similar to the fungus on the fruits of Cacao and 

 Rubber but the other two are apparently new to science. For the first one 

 I propose provisionally the name Phytophthora fici and for the second 

 Phytophthom citri. It is interesting to note that oospores are foand sunken 

 in the outer tissues of the citron fruit. A comparative study of all these 

 forms is being made in this Department when the question of nomenclature 

 will be definitely settled. 



M. K. VENKATA RAU, 

 Senior Assistant Mycologist. 

 Mysore Agricultural Department, 

 Bangalore, 'dth November 1915. 



No. XXXIII.— MALFORMATIONS IN CASUARINA. 

 ( With a Plate.) 



These malformations were observed in Casuarina trees growing in 

 " nullahs " in Bangalore. The " nullahs " are deep waterways often 30 feet 

 deep, formed by the corrosive action of water, which runs in the form of a 

 small stream during the rainy season but is dry during summer. The Casua- 

 rina, which very often grows on the steep sides presenting a stunted and 

 gnarled appearance, rarely attains a height of more than 10 feet, but its root 

 system is very extensive and deep feeding, reaching down to the soft earth 

 below. 



On close examination of the twigs are found long strap-shaped bodies, 

 broader at the top than at the base which often curl up in a fantastic man- 

 ner. These fasciated structures begin to develop in fairly large numbers 

 after the monsoon showers of June but many of them wither away during 

 the dry weather. The buds in the axils of a few develop and give rise later 

 to the normal shoots of Casuarina (PI. Fig. I., a). This fact is in accordance 

 with the idea that fasciation is caused by an excess of water-supply. Exami- 

 nation of material failed to reveal any trace of larvae, which in some cases, 

 is said to inflict slight wounds resulting in fasciation. 



The second malformation observed — occurring on the same twig where fasci- 

 ation develops or another Casuarina tree in the same locality — is a cork-screw- 

 like twisting of the green needle shoots accompanied by a general enlarging 

 in size Q) (PI. Fig. II., b). This spiral twisting has been observed in many 

 Composites, Dipsaceos, Dianthus, Equisetum (-). It is said to occur only in 



(^) Various names have been given to these twistings. A Braun first 



gave the name " zwangsdrehungen", " Strophomanie" (Schim- 



per), Biastrepis (De Vries). 

 (^) De Vries : (Die Mutationstheorie Band II) mentions spiral twisting 



in the case of Casioarina quadrivalvis but his figure (Fig. 126) is 



not at all clear. 



