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THE BRITISH SMUT FUNGI 73<br />
TTstilago tragopogonis-pratensis (Pers.) Roussel<br />
[Uredo tragopogi Persoon, 1797.]<br />
Uredo tragopogi pratensis Persoon, Synopsis, p. 225, 1801.<br />
Ustilago tragopogi pratensis Roussel, Flor. Calvados, p. 47, 1806.<br />
Uredo receptaculorum de CandoIIe, 1808, p.p.<br />
Uredo receptaculorum tragopogi de Candolle, 1815, fide de CandoUe, 1815.<br />
Ustilago receptaculorum (DC.) Fries, 1832.<br />
Ustilago tragopogi de Toni, 1888 [as '(Pers.) Schroet.'].<br />
Sori in the inflorescence destroying the florets. Spore mass powdery, dark<br />
purple. Spores globose or sub-globose to slightly elongated, pale violet, delicately<br />
reticulate (reticulations 1-2 /i diam.), 12-14 /A diam.<br />
On Tragopogon pratensis and T. porrifolius (salsify).<br />
May-June. Widespread.<br />
Exsiccati: Cooke, Fungi. Brit. Exsicc., i, 59; ii, 434; Vize, Fungi Brit., 134.<br />
Spore germination has been figured by Tulasne (1854) (Fig. 2 c), de Bary (1866),<br />
Fischer von Waldheim (1869), and Brefeld (1883). The sporidia arising from the<br />
four-ceUed promycelium are long, almost rod-shaped, 14-24 X 2-5-4-5 /i (Fischer<br />
von Waldheim), 18-22 x 2-5-3 /x (Liro, 1924). They usually bend so that the long<br />
axis is parallel with the promycelium and fuse readily either before or after<br />
detachment. Paravicini (1917) figured the fusion of eUiptical uninucleate<br />
sporidia. Tulasne (1854) germinated the nearly related small spored species on<br />
Scorzonera. The sporidia were very small and oblong and budded profusely.<br />
Fusions were not observed. Brefeld (1883) agreed with Tulasne but Paravicini<br />
(1917) claims to have found fusions in old cultures.<br />
Infection of the host. Liro (1924) showed experimentally that this smut is seedborne.<br />
He failed to get conclusive evidence on the exact mode of transmission<br />
but suggests that flower infection may occur as in loose smut of wheat.<br />
Ustilago kuebneana Wolff<br />
Ustilago kuhneana Wolff, Bot. Zeit., xxxu, p. 815, 1874.<br />
Sori in the inflated ovaries or anthers; itt-'the stems, especially the upper<br />
branches of the inflorescence, as spot-like or elongated blisters which burst to<br />
give spore-filled lesions; less frequently, in the leaves. Spore mass powdery,<br />
pinkish purple. Spores spherical, pale yellow or yellowish brown tinged with<br />
purple, reticulate, 12-20 (av. 13-16 or occasionally more) /x diam.<br />
On Eumex acetosa, B. acetosella, and B. crispus.<br />
June-Sept. England, Scotland. Fairly Common.<br />
Exsiccati: Cooke, Fungi Brit. Exsicc., ii, 436.<br />
Spore germination. Wolff (1874 b) germinated the spores on water and obtained<br />
a three or four-celled promycelium with lemon-shaped sporidia which were not<br />
seen to fuse. Brefeld (1883) figured the sporidia in whorls at each septum. In<br />
nutrient solution they budded profusely and fusions were observed.