•60 T BIN ID AD AND TOBAGO BULLETIN. [XVI 11. 2. 



(h.) The Odoniia (fronp.^k white mycelium, easily distinguishable 

 from that of Marasmius by its feathery pattern of growth and the 

 production of abundant stellate crystals of calcium oxalate, has long 

 been known as apparently capable of producing effects similar to those of 

 Marasmius. It has been commonly refei-red to as the stellate crystal 

 fungus, and, as a mycelium of unknown affinities, was given the name 

 Himant'ia stellifera by J. E. Johnson. Eecently Dr. Burt has described 

 the fructifications of Odontia Sacchari and O. saccharicola from Porto 

 Bico material : two closely related fungi which produce their spores on 

 cane trash in a close lying granular, buff-coloured layer hardly distinguish- 

 jible without the {dd of a lens from the surface of the dry trash itself. 

 J^rom llie constant association and the apparent organic connection 

 of Odontia fructifications with the typical stellate crystal mycelium I 

 was led by observations in Trinidad to believe that the two belonged to 

 the same fungus, and I find on reference to Cane Fungi of Porto Rico 

 by J. R. Johnston and J. A. Stephenson that /he same suggestion has 

 already been made by those authors. The connexion may be regarded 

 as highly probable. 



12. The Odontia type of fungus appears to be much more common 

 in association with root disease in Trinidad than the Marasmius type. 

 The parasitism of both requires detailed investigation. So far as our 

 present knowledge goes their modes of operation may be treated as the 

 same and their effects be referred to without discrimination as root 

 disease. For the sake of simplicity in presentation the myceUum of 

 either or both will l:c referred to as root fungus. 



13. Und.M- ceitain circumstances, to be detailed later, root fungus is 

 commonly \ resent in healthy fields carrying on an inconspicuous 

 existence. Under conditions favourable to vigorous growth of the cane 

 it is practically harmless, but when the vitality of the plant is depressed 

 and growth is slow the presence of the fungus becomes serious. It enters 

 the growing tips of the young roots, distorting tliem, stopping their 

 development and causing them eventually to die. It envelops the young 

 shoots in their various stages, hindering their development by cementing 

 the leaf-sheaths, and in severer cases it infests internally the buds, the 

 young shoots, and the underground connections of tlie stool, and enters 

 to some distance the bases of the developed canes. 



14. The general effect produced by the disease is that of shortage of 

 water, which is brought about by interference with absorption by the 

 roots and conduction by the underground stem system. The leaves of 

 affected shoots have their edges rolled inwards when those of healthy 

 plants are expanded; they eventually turn brown from their edges 

 inward, and in order from below upwards until the shoot is withered to the 

 top. The trash, where it has not been stripped, is cemented firmly around 

 the lower joints of the canes, and under it matted roots occur up to a 

 foot or more from the ground, sent out in an endeavour to find the 

 necessary water. When a clnir.p is infested early it has a characteristic 

 stunted appearance and several or many of the shoots may b3 dead and 

 <lry. Infested btools are easily uprooted and exhibit roots which are 

 mostly either dead or lacking in fibrous branches. 



