Ill 
THE RELATIONSHIP OF PUCCINIA AND PHRAGMIDIUM. 
By Prof. G. de Lagerheim. 
As a distinctive difference between Puccinia and Phragmidium, Tu- 
lasne* asserts that the teleutospores of the first genus are only pro¬ 
vided with one germ pore, while those of the second possess several which 
are equatorially arranged. Since then, however, Dietel t has shown 
that this is not the case in all Phragmidiums, but that in Ph. obtusum , 
Winter, each cell of the teleutospore is provided with only one germ 
pore situated at the upper end of the cell exactly as in the genus 
Puccinia. Ph. abidum , Ludwig, appears to form a transition between 
the two types.j: It should also be mentioned that in Ph. Barnardii , 
Plowright & Winter, and in Ph. carbonarium , Winter, the end cell is 
provided with an apical pore. Besides these characteristics, which are, 
as we see, unreliable, Phragmidium is distinguished from Puccinia by 
the number of cells in its teleutospores and by the different structure 
of its JEcidia. But in several Puccinias we occasionally find many- 
celled teleutospores, and therefore this character is not constant. On 
the contrary the difference in the structure of the tecidium appears to 
be a constant mark of distinction. The tecidium of Puccinia is pro¬ 
vided with a pseudo-peridium, while that of Phragmidium is not; and 
in the latter the spores are cut off from basidia and surrounded only by 
a row of paraphyses as in the genus Melampsora. § 
In the above-mentioned work Dietel has attempted to establish the 
the fact that Phragmidium is more closely related to Chrysomyxa than 
to Puccinia. But in comparing the two genera which he considers to 
be related he has forgotten to notice the difference existing between 
their secidia and uredo stages. As has been said, the tecidium of 
Phragmidium has no pseudo-peridium, while one is present in the tecid- 
ium of Chrysomyxa. The structure of the uredospores of the two genera 
differs even more. In Phragmidium , as in Puccinia and Uromyces , they 
arise singly at the end of a mycelial thread, while on the other hand in 
Chrysomyxa , as in Coleosjwrium , they are borne in rows. I am therefore 
inclined to believe in a closer relationship between Puccinia and Phrag¬ 
midium than between Chrysomyxa and Phragmidium. This supposed 
relationship would become still clearer if one could find a Phragmidium 
with a Puccinia-aecidium or a Puccinia with a Phragmidium-tecidium or 
with several equatorial germ pores. We can probably regard the genus 
Rostrupia\ |as a Phragmidium with a Puccinia-aecidium. The teleutospores 
* Ami. de Sci. Nat. Ser. 4, t. u, p. 146. 
t Beitrage zur Morphologie undBiologie der Uredineen t. n, 9. Figs. 3-7. (Cassel, 
1887.) 
t Compare Dietel, l.c., t. n, Fig. 10, and Miiller Die Rostpilze der Rosa und Rubus- 
arten und die auf iiiuen vorkoramenden Parasiten t. i, tig. 9 (Berlin, 1886). 
$ The genus Cahjptospora, Kiihn, is not to be united with Melampsora, because, as 
is known, the Calyptospora-aicidia have a pseudo-peridium. 
|| Compare Lagerheim, Sur un nouveau genre d’Urddinie&s (Jouru. d. Botan., 1889)> 
Paris. 
