ON IRIS ° 231 
ovate, ochraceous-brown, echinulate, 20—35 x 16—26 w; epi- 
spore thick, with 2—4 (or more) germ-pores. 
Teleutospores. Sori hypophyllous, few and irregularly scat- 
tered, sometimes confluent, oblong, 
compact, persistent, soon naked, 
black; spores clavate or oblong, 
much thickened (up to 14) at the 
summit and rounded, less often 
conical or truncate, gently constric- 
ted, usually attenuated below, 
smooth, fuscous-brown, darker above, 
30—52 x 14-224; pedicels brown- 
ish, thick-walled, persistent, about \ 
as long as the spore. 
On Iris foetidissima, I. Pseuda- 
corus, and on many cultivated Fig. 178. P. Iridis. Teleuto- 
species of Iris. Not common. SEGRE) 00 Ae aeteaeae Tas 
May—October; the teleutospores 
may be found on the old leaves until the following spring. 
(Fig. 178.) 
The uredo-stage is most abundant and assumes various characters, 
especially as regards the formation of spots; when present these are 
conspicuous, oblong or oval, and yellowish, often with a greenish-brown 
circumference. In that case the leaf looks remarkably variegated. 
Plowright considered that the form which occurs on our cultivated 
Irises is different from that on our native species, because he could not 
find any teleutospores in the former ; other authors consider them as the 
same, because the teleutospores on many species are difficult to find, and 
appear only on dying leaves, especially towards the base, at the end of the 
season. One can easily recognise them by their being naked ; for in this 
species, contrary to the usual state of things, the uredo-sori remain long 
concealed by the epidermis and the teleuto-sori soon become uncovered. 
The uredospores are very thick-walled ; they can survive the winter and 
reproduce the fungus in the spring. 
This species might be hetercecious : no experimental cultures appear 
to have been made. It will probably turn out to possess several biological 
races, for it has been recorded on more than thirty-five species of Iris. 
DISTRIBUTION: Europe, Asia, North America. 
