760 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Lichens. 



(By A. Loerain Smith.) 



Physiological Importance of Algae and Fungi in Lichens.*- 

 F. Tobler remarks that, though the separate components of lichen thallus 

 have been long proved, little is known as to the role which each plays 

 in regard to the other. It is desirable to know in what manner, and 

 how far the growth of the fungus is affected by the composite life. 

 Tobler carried out culture experiments on the alga and fungus of 

 Xanthoria parietina, and gives an account of his culture methods. He 

 was able to produce a growth of mycelium from the spores without any 

 admixture of algae, but in such growth there was never any trace of the 

 lichen substance "parietin," so characteristic of the normal thallus. 

 When the mycelium had algae added to it, traces of the parietin were 

 formed. The author proposes to continue his studies on the same lines. 



New Instances of Parasymbiosis.f — The name Parasymbiosis was 

 given by Zopf to the case of those fungi that lived ou the thallus of 

 lichens, associated with the algae, and doing no damage to either thallus 

 or fruit of the host-plant. Zopf proved this for several so-called para- 

 sitic fungi, and now Ignaz Kotte has taken up the research with 

 reference to Abrothallus, which he treats as a fungus, though by some' 

 considered as a lichen. He was able to trace the course of the alien 

 hyphse in the thallus, as they took a blue coloration with iodine, while 

 the host hyphae remained unaffected. Kotte was able to verify Zopf's 

 observations in regard to a symbiotic relationship between the hyphse 

 of the parasite and the algae of the host, the algae remaining healthy ; 

 he also traced the hyphse into the soredia and isidia of the host : and 

 on the dispersal of the soredia it is presumed that portions of the 

 Abrothallus hyphae are carried away and develop along with the new plants. 

 There are five species of Abrothallus on different lichens belonging to 

 the genera Getraria and Parmelia. Rehui had included them all under 

 Abrothallus Parmeliarwn. In two of the species — one on Getraria 

 glauca, another on Parmelia saxatilis and P. conspersa — the hyphae are 

 ■ not stained blue with iodine. 



Malme, G. — Lichenes suecici exsiccati, Fasc. iii.-iv. 



[Includes 50 numbers ; some of them rare species.] 



Stockholm, 1908. See also Bot. Centralbl, cxi. (1909) p. 252. 



Wainio, Ed. — Flora of Koh Chang: Contributions to the Knowledge of the 

 Vegetation in the Gulf of Siam. Lichenes. 



[A list of 95 species, a few of them new to science ; all of them with full 

 diagnoses.] Bot. Tidsskr., xxix. (1909) pp. 104-51 (1 pi.). 



Zahlbruckner, A. — Lichenes rariores exsiccate. Decades xi.-xii. 



[Includes lichens from Germany, Austria, France, and North and South 

 America.] 



Vienna, 1909. See also Bot. Centralbl, cxi. (1909) p. 275. 



* Ber. Deutsch. Bot. GeselL, xxvii. (1909) pp. 421-7 (1 fig.), 

 t Centralbl. Bakt., xxiv. (1909) pp. 74-93 (3 pis. and 1 fig.). 



