418 — Transactions. 
3. CiNTRACTIA Cornu. 
Cornu, Ann. Sci. Nat., ser 4, vol. 15, p. 279, 1883. 
Anthracoidea Bref., Unters. Gesmmt. Myk., vol. 12, p. 144, 1895. 
Sori in the form of a firmly compacted black spore-mass, usually 
surrounding a central columella of host-tissue, situated in various parts ` 
of the host, usually in the inflorescence. 
Spores single, globose or more commonly angular, epispore coloured, 
smooth or verruculose, germination as in Ustilago or slightly modified. 
Distribution : World-wide. 
Of the three species that have beer collected in New Zealand, one is 
endemic, the others indigenous. Eleven species are recorded by McAlpine 
(1906) for Australia, and thirteen for North America by Clinton (1906). 
Members of the genus occur on the families Gramineae, Cyperaceae, 
and Juncaceae. 
e genus is characterized by the (usually) compact sori, central 
columella of host-tissue, and centripetal manner of spore-formation. 
Germination occurs as in Ustilago, but in one species, C. Caricis, the 
apical cell of the probasidium becomes longitudinally septate, each cell 
producing a conidium. On this character Brefeld erected the genus 
Anthracoidea. 
Spore-formation has been studied by Cornu (Lc. p. 269). In the 
А 
aggregated around a central columella of host-tissue ; in this the mycelium 
persists. On the periphery of this columella the sporiferous hyphae develop ; 
they soon become gelatinized, when the whole mass appears as a gelatinous 
cylinder applied to the central columella. These hyphae become septate, 
spores are seen to be little more than gelatinous masses. As the spores 
near maturity the hyaline envelopes surrounding them become absorbed ; 
the spores become exposed and assume a dark colour, but remain firmly 
KEY TO THE SPECIES. 
Spores minute, under 6 . lo is in ficis. 
Spores large, over 10 Weng z pla” 
On Carex. . es oe a; .. 2. С. Caricis. 
On Uncinia és EN гу .. 3. C. sclerotiformis. 
į oe — (Ludwig) McAlpine. (Text-fig. 15, and Plate 45, 
ÉL 
McAlp., Smuts Austr., p. 174, 1910. 
Ustilago Spinificis Ludw., Zeitschr. Pflanzenkr., vol. 3, y. 138, 1893. 
ү Sori in spikelets, frequently concealed within the glumes, destroying 
the ovaries and forming in their stead a compact cylindrical olive-black 
spore-mass, which may attain a length of 7 mm. 
