518 SUMMARY OF CUREENT RESEARCHES RELATING TO 



Sulc, Karel — " Pseudovitellus " und ahnliche gewebe der Homopteren sind 

 Wohnstatten symbiotischer Saccharomycetex (" Pseudovitellus " and similar 

 tissues of the Homoptera as enclosures for symbiotic Saccharomyces.) 



[The fungus is determined as Cycadomyces g. n. ; several new species of 

 Saccharomyces are also isolated.] 



SB. k. Bdhm. Gcs. Wiss. Math.-Nat. CI. (1910) 3, 39 pp. (18 figs.). 



Theiszen, F.— Fungi aliquot Bombayensis a Rev. Ed. Blatter collecti. (Fungi 

 from Bombay, collected by Rev. Ed. Blatter.) 



[A number of rare exotic species are described, several of them new.] 



Ann. MycoL, ix. (1911) pp. 153-9 (1 fig.). 



Lichens. 

 (By A. Lorrain Smith.) 



Nutrition of Lichens.* — F. Tobler points out that certain products 

 in the mutabilisni of lichens are peculiar to them alone, and only pro- 

 duced by fungus and alga combined. It has been held that the fungus 

 received most benefit in the. symbiotic relationship, being dependent on 

 the alga for carbohydrates. Tobler points out that the fungus is often 

 saprophytic on plant remains, scraps of soil, humus, etc., and in some 

 epiphytic lichens even parasitic on the host leaf. Modern writers, who 

 regard the fungus as parasitic on the alga, point out the dead algal cells 

 as proof of their views. Tobler repeats that the fungus takes water and 

 inorganic substances from the soil, and is able as a saprophyte to procure 

 also carbohydrates without the aid of the alga. 



As to the dead algal cells, he points out that assimilation is difficult 

 in the conditions under which they live, badly lighted and deprived 

 largely of carbonic acid gas ; it has, however, been proved that algte can 

 form carbohydrates from organic acids in the absence of light. In 

 homoiomerous lichens the algas are in contact with the substratum, and 

 though oxalic acid may be poisonous for the fungus, there are other 

 sources from which it can derive carbohydrates. It is probable that the 

 fungus often forms an abundance of calcium oxalate, which may be 

 utilized by the alga. Tobler proves from his culture experiments that 

 gonidia grew in certain solutions along with the fungus, but were colour- 

 less, showing that their carbohydrates were procured from some acid 

 formed by the fungus, and proving a physiological symbiosis between 

 the two. He proves step by step : (1) that Xanthoria parietina fungus 

 constituent grown on artificial substratum (poplar bark-gelatin) forms 

 abundant calcium oxalate crystals on the hypha3 ; (2) a piece of thallus 

 grown in the same conditions produces none ; (3) Xanthoria thallus on 

 poplar bark is also without crystals ; (4) finally, in culture solutions in 

 which the Xanthoria fungus had grown, gonidia thrive, but have no colour. 



Lichen Flora of Santa Cruz Peninsula, California/]- — A.W. C. T. 

 Herre has made a special study of the lichen flora of a district measuring 

 90 miles in length and 6 to 35 miles in breadth, rising at one point to a 

 height of 3793 feet, the whole district presenting a great variety of rock, 

 soil, and wood favourable to lichen growth. He found the district 



* Ber. Deutsch. Bot. Gesell., xxix. (1911) pp. 3-12. 

 t Proc. Washington Acad. Sci., xii. (1910) pp. 27-269. 



