238 



A. Barclay — Bescriptice LUt of the Ui-edineoe [No. 2, 



after the spores have rested for a time. I only observed the germination 

 immediately after ripening when a proraycelium was emitted from each 

 cell, that from the upper emerging from the apex, the other from a point 

 near the septum (Fig. 1, PI. XII). The promycelium measures about 

 6 in diameter. I never observed the uredospores germinate. 



7. PucciNiA rLOSCULOsoEUM, (Alb. et Schw.) 



on Taraxacum officinale, Wigg. 



The leaves of this plant are frequently seen from Spring to Autumn 

 bearing dark brown pustules mostly on their upper surfaces. Generally 

 only the youngest entire leaves are thus attacked. Little or no discolour- 

 ation of the leaf tissue is at first occasioned. 



Each pustule contains numerous Puccinia and a few uredospores. 

 These uredospores are chestnut-brown with resistent epispores beset 

 with spines, and thus resemble Uromyces teleutospores rather than uredo- 

 spores ; but their germination reveals their ti-ue character (Fig. 3, PI. 

 XII). When wetted, they are round or oval, measuring 24 /x in dia- 

 meter, sometimes 28 X 22 or 20 (Fig. 2, PI. I). Each uredospore has 

 two germ pores. A few pale single-celled spores may also be found 

 (Fig. 2, PI. XII) with vacuoles, but these are probably immature uredo- 

 spores. 



The teleutospores are readily detached from their beds with only 

 a fragment of stalk adhering. They are chestnut-brown, slightly con- 

 stricted at the septum, rounded at both ends and thickened at neither 

 (Fig. 2, PI. XII). They measure when wetted 36 /u in total length and 

 22 ft. wide at the septum, which usually divides the spore into two equal 

 parts. The epispore of both upper and lower cell of the spore is dis- 

 tinctly tuberculated. I never succeeded in getting these spores to ger- 

 minate. 



Bemarks. — This is probably P. Jlosculosorum (Alb. et Schw.) or P. 

 Taraxaci, Plow, the characters of the uredo- and teleuto-spores agreeing 

 in every respect. But while the European species is associated with 

 SBcidial fructification, this is never found in Simla. Two varieties of 

 the European species are described,* (a.) Forma crepidis and (6) Forma 

 Bieracii (Schum.) The former (a) is associated with an cecicUum, the 

 latter (&) is not. Magnus produced teleutospores of the latter (6) by 

 sowing SBoidiospores from Taraxacum on the leaves of Eieracium, sp. 

 As we have no form (b) in Simla and no JEcidium on Taraocaaum, it 

 would appear that form (h) with its associated JScidium is an entirely 

 different fungus. 



* Winter, loc. oit., p. 207. 



