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70 THE BRITISH SMUT FUNGI<br />

Ustilago violacea (Pers.) Fuckel<br />

Uredo violacea Persoon \pisp. Meih. Fung., p. 57, 1797] ex Persoon, Synopsis,<br />

p. 225, 1801. '<br />

Farinaria stellariae Sowerby, 1803, fide Fries, 1832. ,<br />

Uredo antherarum de CandoUe, 1815 [nov. nom. for U\ violacea Pers.].<br />

Ustilago antherarum (DC.) Fries, 1832.<br />

Ustilago violacea (Pers.) Fuckel, Symb. mycol., p. 39, 1869 [as '(Pers.) Tul.'].<br />

8ori in the anthers (Plate II, Fig. 2). Spore mass powdery, pinkish purple. Spores<br />

spherical or sub-spherical to elUpsoidal, tinted pa-le violet or almost hyahne,<br />

delicately reticulate (reticulations about 1 fj. diain.) 5-12 (av. 7-8) /A diam.<br />

On Cerastium viscosum, Cucubalus baccifer, Dianthtts caryophyllus (cultivated<br />

carnation). Lychnis flos-cuculi, Melandrium album, M. dioicum, Silene acaulis,<br />

S. alsine, S. cucubalus, S. maritima, S. otites, Stellaria graminea, and S. holostea.<br />

May to October (and at other times on carnations under glass). Widespread.<br />

Common.<br />

Exsiccati: Cooke, Fungi. Brit. Exsicc, ii, 427; Vize, Fungi Brit., 34; Vize,<br />

Micro. Fungi Brit., 569.<br />

Spore germination. Spores of this species germinate easily when fresh and remain<br />

viable for some time. Tulasne (1847) described the septate promycelium<br />

which falls somewhat easily from the spore. Schroeter (1877) described the<br />

sporidia from the smut on Dianthus carthusianorum as elliptic, often flattened on<br />

one side, 4x2-3 /x. Fischer von Waldheim (1869), Brefeld (1883), and Schellenberg<br />

(1911) also figured germination and it has been accepted as a type which<br />

like U. avenae readily produces a four-celled promycelium with sporidia sprouting<br />

from each cell. PlowTight (1889) germinated spores of the form known as<br />

U. major on Silene otites and Liro (1924) described fusion between sporidia in<br />

the form on Silene vulgaris [S. cucubalus]. According to Harper (1899) who<br />

studied nuclear division in the sporidia, one nucleus may remain in the spore<br />

and a second or third promycelium develop after the first has fallen off. Fusions<br />

readily occur in cultures several days old between appropriate cells of the promycelium,<br />

between these and sporidia, or among the sporidia and their progeny.<br />

Paravieini (1917) also figured fusions of uniaucleate sporidia. The classic work<br />

of Kniep (1919, 1928) which established heterothalHsm in the Ustilaginales was<br />

conducted on this species (see p. 29).<br />

Infection of the host. The fungus can infect the plant through seedlings, underground<br />

shoots, and axOlary buds (Hecke, 1907,1926; Werth, 1913; Zfilig, 1921;<br />

Liro, 1924). It is apparently not carried by the seed as in loose smut of wheat,<br />

but if spores are sown on the ovaries of healthy flowers the fungus will invade the<br />

plant and a few months later the newly formed blossoms haye infected anthers.<br />

When female plants are attacked, the flower develops on a longer floral axis and<br />

has a cylindrical calyx more like that of the male. Stamens which would<br />

normally remain rudimentary develop and contain chlamydospores as on infected<br />

male plants (Werth, 1913, Fig. 1).<br />

Racial specialization. ZilHg (1921) recognized eight physiologic races of anther<br />

smut and showed that the fungus would not pass between two such closely<br />

related hosts as Melandrium album and M. dioicum. Liro (1924) tabulated the

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