306 GYMNOSPORANGIUM 



. Keidia <>ii Crat'iiyiis Oxyoanttha, C. rnonogyna, Pyrus 

 communis. July — Augusl : teleutospores on Juniperus com- 

 munis, April and May. Rather common. (Figs. 230, 231.) 



The teleutospore-mycelium is perennial in tin- branches of the Juniper ; 

 the sporea are produced in spring and germinate immediately. The 



;rciili;i cm We produced <>n the Hawthorn in two to four weeks or more 

 after infection. Their spores in turn infeel young shoots of Juniper, 

 in which the mycelium gives rise to teleutospores in one year (von Tubeuf), 

 ortwo years Plowrighi , and in each succeeding" year so long as the branch 

 survives. The mycelium in Crataegus is purely local and annual. 



The experimental culture of this species has been performed 

 unnumbered times by many mycologists ; the secidia have been produced 

 on several specie-, of Crataegus and possibly on the Apple and the Medlar ; 



also (spermogones only in som n Cydonia, Sorbus, and Avielanchier 



and the teleutospores on Juniperus nana and ./. oxycedrus, as well as 

 on •/. count} "nix. This culture is one of the easiest to perform of all that 

 are known among the Uredinales. 



The only means of checking this disease on the pomaceous hosts is by 

 the removal of the affected Junipers, if thej can be found. 



Distribution : Europe, Algeria, North America. 



2. G-ymnosporangium confusum Plowr. 



JEcidium Mespili DC. Flor. Fr. vi. 98. 



Roestelia Cydoniae Thiim. in Sacc. Syll. vii. 834. 



Gymnosporangium confusum Plowr. Ured. p. 232, pi. 4, f. 13, 14. 



Fischer, Ured. Schweiz, p. 385, f. 276 ; Zeitschr. f. Pflanzenkr. 



1891, i. 193, 260. Sydow, Monogr. iii. 56, f. 27. 



Spermogones. Orange-coloured. 



jEcidiospores. /Ecidia on thickened spots, obconical or 

 cylindrical, opening at the summit which is at length fimbriate, 

 orange above, often surrounded by a reddish or purple line ; 

 spores verruculose, pale-brown, 21 — 24 /x. 



Teleutospores. Spore-masses at first pulvinate, dark choco- 

 late-brown, almost black, then irregularly conical, 5 — 8 mm. 

 long, chestnut-brown, swelling when moist ; spores oval to 

 fusiform, smooth, of two kinds, some with hyaline spore-walls 

 and orange contents, tapering above, others with dark-brown 

 thick walls, rounded above, about 30 — 50 x 20 — 25 /x ; germ- 

 pores 2 — 4 ; pedicels hyaline, rather long. 



