. Fig. ()Z.—Melampsora pinito?-qua. i, top of young pine attacked by the aecidium stage; 2, two chains of aecidiospores ; 3, aspen leaf with sori of teleutospores ; 4, section of cushion of teleutospores, still covered by the epidermis. Figs, i and 3 nat. size ; remainder mag. as the fungus appears year after year if damp weather prevails in May and June; this indicates that the fungus is peren- nial in the tissues of the host. In the seed-bed or young plantation the disease usually spreads from a centre, due to infection by wind-borne spores, showing that the aecidiospore stage is capable of
. Fig. ()Z.—Melampsora pinito?-qua. i, top of young pine attacked by the aecidium stage; 2, two chains of aecidiospores ; 3, aspen leaf with sori of teleutospores ; 4, section of cushion of teleutospores, still covered by the epidermis. Figs, i and 3 nat. size ; remainder mag. as the fungus appears year after year if damp weather prevails in May and June; this indicates that the fungus is peren- nial in the tissues of the host. In the seed-bed or young plantation the disease usually spreads from a centre, due to infection by wind-borne spores, showing that the aecidiospore stage is capable of perpetuat- ing the disease, without the intervention of another condi- tion of the fungus. Spermogonia and aecidia appear on the
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Photo credit: © The Bookworm Collection / Alamy / Afripics
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Keywords: ., bookpublishernewyorkmacmillan, booksubjectplantdis, bookyear1910
