REVIEWS. 



The Genus Ravenella. 



[P. Dietel. Monogi'aijliie der Gattung Bavenelia, Berk. Bei- 

 hefte zum Botanischen Centralblatt. Bd. XX., Heft 3, pp. 343- 

 413.] 



The genus Bavenelia was founded by Berkeley in 1853, the 

 first species being jB. indica. Berk. When Cooke monogi-aphed 

 the genus in 1880, eight species liad been described, six of which 

 were from Asia. Since then only one more species has been 

 recorded from Asia, though the total number in the genus has 

 been increased to eighty-one, chiefly from America. (Butler 

 has added two new species from India, since the publication of 

 Prof. Dietel's monograph.) The genus belongs to the Uredinece, 

 and is characterized by the growth of the teleutospores in stalked 

 or sessile heads furnished with peculiar basal " cysts." It is 

 confined to tropical or subtropical regions, and, except tlu'ee, 

 all members of the genus are parasitic on species of Leguminosce, 

 the exceptions occurring on Phyllanthus. 



The Ceylon species ai'e six in number. R. sessilis. Berk., is 

 parasitic on the leaves of Alhizzia Lebbek ; R. acideifera. Berk., on 

 Mezoneuron enneaphyllum ; R. indica on Cassia absus ; R. niacro- 

 cystis. Berk. & Br. , on Cassia Tora ; R. Hobsoni, Cke. , on Pongamia 

 glabra ; and R. munduleoi, Henn., on Mtmdulea suberosa. The 

 two last were inckided hy Berkeley under R. stictica. Berk. & Br. 

 With regard to R. macrocystis, Dietel states that there is no 

 fungus on the specimen at Kew, and that the species was not seen 

 by Cooke : there is no specimen in the Peradeniya lierbarium. 

 Cassia Tora is a very common weed in Ceylon, and I have ex- 

 amined all the plants I have seen dm'ing the last two years in 

 various parts of the Island. The fungus which always occurs on 

 it — the only one collected from this plant — is an Erysiphe which 

 causes black patches on the leaves. As Berkeley and Broome 

 do not record this, though it could scarcely have been overlooked 

 by Thwaites, it seems a fair suggestion (in view of the man' 

 errors in the list) that R. macrocystis was a misdeterminatiouj 

 more especially as Berkeley and Broome state that it is " Pseudo- 

 sporis e cellulis paucis niagnis compactis e mycelio radiante 

 oriundis.''^ 



Berkeley's R. sessilis was said to be on Albizzia Lebbek (Thwaites 

 1,105) and Gleditschia, sp. (Thwaites 1,135). Dietel observed 

 that the latter host plant was wTongly determined, and instituted 

 a new species, R. zeylanica, for the fungus on it, but this has 

 since been withdrawn (Bot. Centralb. Bd. 104, p. 209). Thwaites' 

 specimen No. 1,136 labelled " Gleditschia, sp." is undoubtedly on 



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