174 C'lntractia. 



Sjnnijex. 

 30. Cintractia spiniflcis (Ludw.) McAlp, 



Luclwig, Zeitsclir. Pflanzenkr, III., p. 138 (1893). 

 Brefeld, Uuters. Gesammt. Myk. XII., p. 106 (1895). 

 Sacc. Syll. XL, p. 231 (1895). 

 Ustilago spiniflcis Ludw. 



Sori in spikelets generally concealed by the glumes, destroying ovaries 

 and forming a dense tough brownish mass of spores. 



Spores globose to shortly ellipsoid, pale olivaceous to brownish, 

 very minute, epispore finely punctulate, 3-4 /t diam. or 5 x 3 f/. 



On Spinifex hirsutus Labill. 



South Australia — Near Port Adelaide, Dec, 1892 (Tepper). 



In the large dense globular head of this grass all the ovaries were des- 

 troyed and more or less completely replaced by a mass of spores which re- 

 main firmly united. This grass is often called the " Spiny Rolling Grass," 

 since the flower heads of the female plant become detached on ripening and 

 are easily rolled about by the wind, at last sticking in the sand, and the in- 

 dividual spikelets separate. In this way the smut, hke the plant itself, is 

 widely distributed and probably occurs all round the Australian coast. 



Brefeld' has specially examined this species and found that in water the 

 spores readily separate. 



Spore formation. — A cross-section of the ovary shows the plant tissue 

 in the centre with the surrounding spores embedded in it. The plant tissue 

 consists of the large-celled parenchyma studded with fibro-vascular bundles, 

 in which numerous vessels are visible. Towards the outside there is a dense 

 layer of exceedingly fine fungus filaments felted together, yellowish in the 

 mass and forming a stroma from which numerous slender hyaline fungus 

 filaments project. In these the spores are developed, at first as minute colour- 

 less points, which gradually increase in size and assume a dark tint towards 

 the outside, until finally they form the dense firm brownish mass of mature 

 spores, arranged in rows and embedded in a gelatinous material. They burst 

 through and rupture the epidermis as they become mature, and the unbroken 

 epidermis may be seen alongside. 



The s^pores are also formed in the interior, in cavities in the tissue. Sur- 

 rounding the cavity there is the dense yellowish stroma from which the 

 sporogenous hyphae project towards the centre and ultimately the cavity 

 is filled with a dense mass of spores which escape by disruption of the tissue. 



Germination. — The spores germinated after being kept for about two 

 months, not in wafer in which they remained unchanged, but directly on 

 the addition of nutritive solution. The promycelium was typically four- 

 colled and relatively large in comparison with the spore, each individual cell 

 being about equal in length and thickness. Below each septum and at the 

 apex, elongated conidia are slowly formed which multiply by a process of 

 }'cast-like budding. Just before the solution is exhausted, the conidia may 

 p,row out into filaments, and if these reach the air they form aefrial conidia. 

 .So ,srcneral and so copious is this development in contrast to the rather sparing 

 multiplication within the solution, that the conidia form a fine film on the 

 surface like delicate down. 



(Plato XXXII.) 



