Fig. 154.—Gymnosporanginum juniperinum: a a small leaf with three clusters of æcidia (nat. size); b three conidia; c two æcidiospores on one of which are seen the germ-pores; d a portion of the wall of an æcidium; e, f two teleutospores.
Fig. 155.—Coleosporium senecionis: a Pine-leaves with æcidia (Peridermium wolffii) nat. size; b an æcidiospore; c a germinating æcidiospore; d a chain of uredospores; e a chain of teleutospores of which the terminal one has germinated and produced a basidiospore (s).
Cronartium (Figs. [157], [159]) has unicellular teleutospores united in numbers to form erect threads or columns; the uredospores are enclosed in a “peridium”; C. ribicola (Fig. [157]), on leaves of Ribes (especially Black Currants); its æcidia (Peridermium strobi, or P. klebahni) on the stems and branches of Pinus strobus (Fig. [159]), on which it causes great damage; C. asclepiadeum, on Vincetoxicum officinale; its æcidia (Peridermium cornui) on the stems and branches of Pinus silvestris.
Fig. 156.—Chrysomyxa abietis: a leaf of the Fir, with 5 clusters of basidiospores (× 4); b branched rows of teleutospores springing from the mycelium (m).
Fig. 157.—Cronartium ribicola: a mass of uredospores (× 50); b an uredospore; c a column of teleutospores (× 60); d a small portion of the same more highly magnified, with a basidium and two basidiospores (s).
To the Fungi of which the æcidium is known, whilst the remaining forms are still undetermined, but which are without doubt heterœcious, belong Æcidium elatinum, which produces the enormous “witches’ brooms” and barrel-shaped swellings on stems and branches of Abies alba; and Æcidium strobilinum (Fig. [158]), which attacks Fir-cones, causing all the scales to become covered with clusters of æcidia opening by a lid. Hemileia vastatrix destroyed the coffee plantations in Asia.