416 



UREDIXKAK. 



P. Ravenelii Thiiin. On Pim.ix nmttfuUx in North America (probably 

 a variety of /'. oblongisporiuin). 



P. deformans Mavr. On I'iimx //!///.< in Anierir;i. 



P. giganteum (Mayr). On Pimis densiflora and P. T/omlerifii in Japan. 

 This causes very conspicuous deformation of its host (Figs. 249 and 250). 



P. complanatum Barcl. On 1'inn* luinjilol/o in India. 



The following species frequent other hosts : 



Peridermium conorum Tlnim. 1 This aecidium first found by 

 De 'Bary in Thiiringia, has recently been reported in Denmark, 



liussia, and America ; also in 

 Upper Bavaria by v. Tubeuf 

 in September, 1895. It takes 

 the form of two large aecidia, 

 which make their appearance 

 on the outer or inner side of 

 the cone-scales of spruce. The 

 white peridia break through 

 the epidermal tissues which 

 then remain as a brownish 

 sheath around each ruptured 

 peridiuin (Fig. 251). The 

 spores are separated by inter- 

 mediate cells, and their outer 

 coats are studded with poly- 

 gonal warts. The cone-scales 

 bearing aecidia contain a very 

 large quantity of starch. Tel- 

 eutospores of the species are 

 unknown. 



Peridermium coruscans 

 Fries. 2 The mycelium of this 

 fungus seems to perennate in 



twigs and buds of spruce. Twigs unfold from the bud as 

 deformed, shortened, cone-like shoots bearing very short broad 

 needles of a pale colour. The aecidia are produced on the 

 deformed needles as broad lineal cushions with white peridia. 

 They originate under the epidermis which they rupture, and 

 break out on one side of the needle. 



'IK, 



FIG. 251. Aecidium conorum-piceoe. /;, Peri- 

 dium ; sj>, spore ; ~w, intermediate cells ; x/it,-. 



lnyc 



J Reess, Rostpilzformen, 186!). 

 2 Rostrup, 



/., ISM. 



