TRANSACTIONS OF SECTION K. 931 



low day-temperature maxima. Smoke and fog-production. Long-continued smoke 

 fog of February 1891. Darkness in and around large cities. Effect of smoke on 

 mosses and hepatics as compared with that on higher plants. Smoke at a maximum 

 in winter, when many mosses are in a vegetative condition. Great diminution in 

 their abundance and luxuriousness in the neighbourhood of large towns. Peculiar 

 exposure of bark-loving species to smoke influence, and the cause. Threatened 

 extinction of Ulota and OrtTwtricha. 



5. A Gymnosporanghi'm from China. By F. E. Weiss. 



This fungus was fii-st observed by Dr. A. G. Parrott in the spring of 1899 in 

 Lao-ho-kou, in North Central China (lat. 32° 50' N., long. 112* E.). Its spore 

 masses made their appearance in April on the branches of Junipertis chinensis in 

 the form of bright yellow gelatinous masses after a few days' continuous rain. The 

 teleutosp ore-beds appear singly or in clusters on the leaves of the smaller branches, 

 usually in more or less flat leaf-like masses. When close together they often 

 become confluent. The teleutospores are of the usual type, two-colled, tapering 

 towards both ends and somewhat rounded at the apex. They possess eight germ 

 pores. 



What is in all probability the Rcestelia stage of this fungus was observed 

 during the summer on the leaves of the pear, Pyvus sinensis, Ldl. A tree of this 

 species growing in proximity to the infected junipers was attacked by a fungus of 

 the Rcestelia type, producing typical secidiospores. 



In the appearance of its teleutospore masses and in the shape and structure of 

 the teleutoa'porea this fungus appears most nearly related to Gymnosporangiuvi 

 SahincB (Dicks), a widely distributed form occurring in Europe and in America, 

 and to Gyinnof.porangium Cunninghamianum (Barclay), a Himalayan form, both 

 of which have their Roestelia stage on a pear, the former on Pyms communis, the 

 latter on Pyrus Pashia, 



6. Demonstration of the Structure and Attachment of the Flagelhim in 

 Euglena viridis. By Harold Wager. 



The flagellum of Euglena viridis possesses a bifurcate base, which is attached 

 to the wall of the excretory reservoir at the anterior end of the body.' As it 

 passes to the anterior, through the gullet, an enlargement occurs in the region of, 

 and partly surrounded by, the eye-spot. This structure can be seen in very favour- 

 able cases in the living condition, but usually only after the action of reagents. 

 The best reagent for this purpose is either a 1 per cent, solution of osmic acid or 

 a 2 per cent, solution of bichromate of potash with a 1 per cent, solution of osmic 

 acid. Good preparations have also been obtained by treating fresh cells with a 

 solution of iodine. 



The structure may be obscured by small grains of paramylon which sometimes 

 accumulate at the anterior end of the body. 



7. On the Structure of the Root-nodules of Alnus glutinosa. 



Byl. W. WOODHEAD.. 



Longitudinal sections show that the nodule is traversed by a central strand of 

 short, thick-walled, prosenchymatous fibres, with transverse pits in the walls. 

 Surrounding this are four or five layers of cubical cells, rich in protoplasm, followed 

 by a small-celled bulky cortex. On the outside of this is a phellogen, which pro- 

 duces a layer of cork several cells deep. The cortical cells are largely occupied 

 by the organism which produces the nodule. Their distribution is roughly in 

 parallel layers of cells passing obliquely from the central strand outwards ; between 



' See Wager, Journal Linn. Soo. Zoology, vol. xxvii. p, 463. 



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