236 SUMMARY OF CURRENT RESEARCHES RELATING TO 



The substance previously described by the author as parinelial acid is 

 identical with lecanoric acid. A new colourless crystallisable substance, 

 which he names glomelliferin, was obtained from Parmelia glomellifera. 



Secretion of Oil by Calcareous Lichens. * — Herr M. Fiinfsttick 

 maintains, in opposition to Zukal, his previous view that the oil secreted 

 by calcareous lichens is an excretory product, rather than a reserve food- 

 material. His observations were made chiefly on Verrucaria calciseda 

 and Opegrapha saxicola. The oil-hyplite retain their character after 

 the lichen has been placed for some months in the dark. This nature 

 of the oil-hvphas is especially well seen in Petractis exanthematica, where 

 the gonid-element is a Scyfonema, and the hyphse in question are scarcely 

 distinguishable in appearance from the iSfc^owema-goniils. 



Development of the Apothece of Physcia pulverulenta.f — Mr. 0. 

 V. Darbishire gives a preliminary account of the complicated processes 

 connected with fertilisation in this lichen. He finds no evidence in 

 support of Lindau's view that the trichogyne serves as a " terebrator" 

 or borer through the soft tissues, the structure of that organ not adapt- 

 ing it for such a purpose. The carpogones occur in very large numbers 

 in the lobes of the thallus, but only a few of them develope. The carpo- 

 gone consists of from thirty to forty cells. Its lower part, the ascogone, 

 is composed of a row of cells, which is coiled or irregularly serpentine. 

 The trichogyne makes its way between two clusters of gouids, its apex 

 passing through the cortex. Spermatia (poliinoids) were found attached 

 to the apex of the trichogyne ; but, owing to their minute size, the actual 

 process of impregnation could not be followed out. After the carpogone 

 has been impregnated, the central cells of the ascogone become connected 

 with one another by wide bridges of protoplasm. Lateral branches are 

 formed, the apices of which develope iuto asci surrounded by para- 

 physes. 



Rusts of Cereals. J — Mr. M. A. Carleton has brought out an exhaus- 

 tive monograph on the cereal rusts of the United States, the nature of 

 the injuries which they inflict, and the best remedies. They are six 

 or probably seven in number i—Puccinia rubigo-vera Tritici, the orange 

 leaf-rust of wheat, P. rubigo-vera Secalis, the orange leaf-rust of rye, 

 P. coronata Corda, the crown-rust of oats, P. graminis Tritici Eriks. and 

 Henn., the black stem-rust of wheat and barley, P. graminis Secalis Eriks. 

 and Henn., the black stem-rust of rye, P. graminis Avense Eriks. and 

 Henn., the black stem-rust of oats, and P. Sorghi Schur., the rust of 

 maize. By far the most destructive of these fungi are the black stem- 

 rusts of wheat and oats. The uredospores of the orange leaf-rusts of 

 wheat and rye do not appear to attack hosts outside the genera Triticum 

 and Secale ; while the black stem-rust of wheat occurs also on barley and 

 on Hordeum jubatum. A useful bibliography is appended. 



Rabenhorst's Cryptogamic Flora of Germany (Fungi Imperfecti) 

 Lief. b7-69.§ — The latest three parts of this important work (by A. 

 Allescher) complete the account of Vermicularia (54 species in all), and 



* Festschr. f. Schwenrlener, 1899, pp. 341-56. Cf. this Journal, 1896, p. 95. 

 t Pringsheim's Jahrb. f. wiss. Bot., xxxiv. (1809) pp. 329-45 (1 pi.). 

 : Bull. No. 16 U.S. Dptmt. Agriculture (Div. Veg. Phys. and Path.), Washing- 

 ton, 1899, 74 pp. and 4 pis. § 1899-1900. Of. this Journal, 1899, pp. 192, 633. 



