Spore Germination in Onygena equina, Willd. 
BY 
WILLIAM B. BRIERLEY 
{Late Lecturer in Economic Botany , Manchester University ), Laboratory of 
Plant Pathology , Royal Botanic Gardens , Kew. 
/ ~\NYGENA EQUINA, Willd., is a somewhat rare ascomycetous fungus 
occurring on decomposing horns and hoofs of cattle, sheep, horses, &c. 
The fructifications are globular and stalked, pseudo-parenchymatous in 
texture, and dehisce irregularly. The asci are very evanescent and the 
spores when ripe fill the peridium as a loose powdery brown mass mixed 
with ‘capillitium fibres’. During the growth of the sporocarp abundant 
chlamydospores are developed, which form a peripheral crust enclosing the 
dome-shaped mass of the young fructification. 
Prior to Marshall Ward’s investigations 1 the conditions of ascospore 
germination were unknown, although of the related species, O. corvina , de 
Bary 2 had made the significant observation that the spores refused to grow 
in water or nutrient solutions, or in gastric juice, at any temperature, ‘ but 
there was a fine formation of compound sporophores of Onygena on the 
hairs cast up by a white owl . . . which had received the spores of the fungus 
with a mouse which it had eaten. The fungus developed on the hair from 
the mouse on which the spores had been strewed and from no other.’ 
Ward also found that ascospores placed directly in water or various nutrient 
media refused to germinate, but, following the clue given by de Bary’s 
observation, caused their germination by subjecting them to a preliminary 
digestion in artificial gastric juice. De Bary had tried this method using 
extract of pig’s stomach, and his failure must be attributed to some 
accessory circumstance. 
Marshall Ward found that the chlamydospores also germinated readily 
after digestion with gastric juice, but later discovered that, in certain 
nutrient media, their germination was possible in the absence of such treat- 
ment, although apparently considerably promoted by it. 
On January 2, 1914, a large ram’s horn bearing sporocarps of Onygena 
1 H. Marshall Ward : Onygena equina , Willd., a Horn-destroying Fungus. Phil. Trans. Roy. 
Soc., B, vol. cxci, pp. 269-91, 1899. 
2 A. de Bary: Comp. Morph, and Biol, of the Fungi, etc., p. 351, 1887. 
[Annals of Botany, Vol. XXXI. No. CXXI. January, 1917.] 
