390 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Larch Rust. 

 Cceoma laricis (West), PL XXI. fig. 53. 



Found early in the year on the foliage of the Larch, but so incon- 

 spicuous that it is easily overlooked. 



The pustules are seated on yellow spots, and are surrounded by the 

 remains of the ruptured epidermis and a circle of barren cells. The 

 uredospores are subglobose, or somewhat elliptical, minutely rough 

 (15-25 x 12-18 ju), and of an orange-yellow colour. 



A suggestion has been offered that this rust is connected with a form 

 of Melampsora tremulce, but at present the evidence of such a relationship 

 beyond the fact of their growing in proximity, is confined to Hartig. 



Known also in Belgium and Germany. 



Sacc. Syll. vii. 3128 ; Ploivr. Br. Ured. p. 262 ; Grevillea, xiii. p. 73 ; 

 Hart, d Som. Dis. Trees, p. 169, fig. 100. 



Hysterium laricinum is liable to infest the leaves of Larch. It is more 

 accurately called Lopliodermium laricinum (Duby). 

 Sacc. Syll. ii. 5821. 



Larch Canker. 

 Dasyscypha calycina (Fckl.), PI. XXI. fig. 54. 



The Peziza which establishes itself on the twigs and branches, and 

 declared by some observers to be the cause of the Larch disease, consists 

 of pretty little cups (J to 1 line broad) which are either clustered or 

 scattered, are at first hemispherical, soon manifestly stipitate, and of a 

 waxy consistency, externally white and hairy. The disc is orange-yellow, 

 with an entire margin. Stem short and rather stout, expanding upwards 

 into the base of the cup. The asci, or spore-sacs, are cylindrical, closely 

 packed to form the disc, enclosing eight oblong, elliptic sporidia (18-22 

 x 7 /u), mixed with thread-like paraphyses, scarcely thickened upwards. 



Recorded in Germany, France, and Italy, where it is sometimes called 

 Peziza Willkommii. 



Sacc. Syll. viii. 1822 ; Phil. Br. Disc, p. 241 ; Hart. & Som. Dis. Trees, 

 p. 117, fig. 58-60 ; Mass. PL Dis. 145, fig. 30 ; Cooke, Hdbh. No. 2034 ; 

 Marshall Ward, Timbers etc. p. 227, 34-36. 



EXPLANATION OF PLATES XIX., XX., XXL 



Fia. 1. — Phyllosticta aceriv, Sacc. — a, section of perithecium enlarged ; 6, conidia x 

 400. 



2. — Pklaiospora aceris> Lib. — a, section of perithecium ; b, conidia x 400. 

 '6. —Septogl&um liar tig ianum, Sacc. — «. twig with pustules ; b, section of pustule ; 

 c, conidia x 400. 



4. — Botrytis dep rc/jdaus, Cooke. — Portion of capitulum x 400. 



5. — Rhytisma acerinum, Fries. — a, conidia ; 6, ascus and ascospores x 400. 



0. — Uncinula aceris, DC. — a, receptacle enlarged ; b, tip of appendage enlarged ; 



c, ascus and ascospores x 400. 

 7. — Rhytimna punctatum, Fries. — a, conidia ; 6, ascus and ascospores x 400. 

 9. — Ghrusporium ncrviacquinn, Fckl. — a, conidia x 400. 



10. — Scptvria hippocastani, 13. A- Br. — a, section of perithecium ; b, sporules x 



400. 



11. — S i cream purpura um, Fries. — a, basidium with spores x 400. 



