Lecture V — 61 — Distribution 



out the whole range of that tropical flora. In the course of a study 

 of parasites of the coffee-tree, Janse's attention was drawn to fungi 

 on roots, and from that beginning he was led on to make an extensive 

 study of roots of tropical plants. It seemed preferable to study plants 

 from native haunts and hence almost all material was taken from the 

 forest at Tjibodas, which belongs to the Botanical Garden and is 

 situated on the flanks of the Gedeh volcano at an altitude of 1400-1800 

 m.A.T. The flora of E. Java is of an extraordinary richness and, as 

 it was impossible to study the roots of all the plants, he decided to 

 omit ectotrophic sorts entirely and to devote his attention to the 

 endotrophic, mostly of large forest trees. In general, only a single 

 species of each family represented at Tjibodas was studied ; and in this 

 logical way Janse built up his excellent study, which nevertheless is 

 only a preliminary one. He summarized his results in a graphic table 

 which is here reproduced, showing the numbers of plants studied in 

 each taxonomic group, with and without mycorrhizae : 



Tabular summary of endotrophic mycorrhizae in some Javanese plants: — 



Total 46 23 6 69 6 



Several years before Janse published his paper, Goebel had 

 written on hepatics (1891) and Lycopodimn (1888) at Tjibodas and 

 their fungal infection. Miehe (1911) had called attention to vegeta- 

 tion on volcanic soil in Java, the pioneer plants being provided with 

 root symbionts. He suggested that there is a significant relation 

 between occurrence of these plants and soil conditions, naming Casiia- 

 rina, Myrica, Alhizsia, and two ericads as particularly involved. 

 Faber (1925) confirms these suggestions, stating that all the investi- 

 gated solfatara plants are mycorrhizal, the root symbiosis apparently 

 serving for N assimilation since the soil is very poor in N. He notes 

 among these plants two groups, one xeromorphic as the ericads, and 

 the other more nearly hygromorphic. 



Some special studies of Java plants are to be noted : Treub (1885) 

 reported a Pythium in roots of sugar cane; Figdor (1897) on the 

 gentianaceous Cotylauthera tenuis; Campbell (1907) on Ophioglos- 

 siim; Steinmann (1929) on mycorrhizae of Cinchona which, he 

 said, is the first report for this tree; Pijl (1934) on mycorrhizae of 

 Burmannia and Epirrhisanthes. 



