466 
PUCCINI A ON GROUNDSEL, 
Link, should be raised to specific rank. The Puccinias which he 
enumerates as occurring on Senecio are : — P. conglomerata, P. 
senecionis, P. expansa and P. uralensia; P. tfanzschelii is also 
given, but it is now regarded as a variety of P. co?iyl»merata. In 
P. uralensis* the sori are hypophyllous, the teleutospores are much 
shorter (36-43 p), and no aecidiospores are known, so that the 
distinctness of this species is still maintained. When the proper 
season comes round, infection experiments will be carried out 
mutually on Senecio vulgaris and Erechtites quadrvtentata. 
Trimorphic Teleutospores. 
There are three forms of teleutospores in this species, as 
already stated — normal or uniseptate, aseptate and biseptate. 
A similar case was recorded by W. B. Grovef in Puccinia 
beta niece, DC, belonging also to the Pucciniopsis, in which he 
found one-celled, two-celled and three-celled teleutospores. Since 
then several similar cases have been brought to light, and even 
four-celled spores have been observed in Puccinia (jramirds, Pers. 
In Puccinia saccardoi, Ludw., an Australian species on Goodenia 
geniculata, Dr. Ludwigj records the occurrence, among the 
normal teleutospores, of unicellular and tricellular spores, some- 
times of enormous size, and occasionally singular horn-like 
branching spores, resembling those of Phra puidium obtusum. 
The whole subject is very fully and ably discussed by Dr. P. 
Dietel in his paper on " Beitrage zur Morphologie und Biologic 
des Uredineen."§ The one-celled spores are commonly known as 
mesospores, and various views are held as to their meaning. 
Winter] | regards them simply as unicellular teleutospores and 
SorauerU considers them as transition forms between uredospores 
* Zeitsch. f. Pflanzk. Vol. ii. Pt. 2, 104 (1892). 
t Gardener's Chronicle, Vol. xxiv. p. 180 (1885). 
X Hedw. xxviii. pp. 362, 363 (1890). 
§ Bot. Centralb. Vol. xxxii. (1887). 
II Die Pike, Vol. i. p. 133 (1884). 
IT Prtanzenkrk. Vol. ii. p. 213 (1SSG). 
