194 
MILDEWS, RUSTS AND SMUTS 
Ustilago kuhneana, Wolff; Plowr., Ured., p. 281. 
On the stem, leaves and flowers, forming patches or 
streaks, rusty violet ; spores globose or angularly globose, 
dusky violet, wall covered with a network, 10—16 p ; 
promycelium 2—3-septate, promycelium spores very minute. 
On Rumex acetosa and R. acetosella. Germany and 
Italy. 
C. Spores produced on the root, rhizome, etc. 
Ustilago marina, Durieu ; Plowr., Ured., p. 275. 
Forming blackish-brown, swollen sori on the root of the 
host-plant ; spores of two kinds, one form subglobose or 
broadly egg-shaped, 10—13 11, the other irregularly ellip¬ 
tical or egg-shaped, 16 x 10—13 [i., wall thick, pale olive- 
brown, smooth. 
On rhizomes of Scirpus parvulus. 
A very doubtful species, respecting which but little is 
known, 
Ustilago hypogaea. Tub ; Plowr., Ured., p. 276. 
Forming blackish, compact sori round the root of the host- 
plant ; spores subglobose or polygonal, dark brown, smooth, 
crowded with oil-globules, 20—-24 X 14—20 [ji. 
On the rootstock of Linaria spuria. 
A doubtful species. 
TILLETIA, Tub 
Parasites developing in the interior of plant tissues. 
Spore-mass blackish and powdery when mature, often 
foetid, especially when moist. Spores produced singly at 
the tips of somewhat gelatinous, swollen, fertile hyphae, 
at first covered by the epidermis. On germination the 
spores produce a promycelium, which bears a terminal 
whorl of slender secondary spores. These secondary 
spores usually conjugate in pairs, and on again germinating 
give origin to slender, elongated conidia. 
The principal feature of the present genus consists in the 
free spores forming a dry, powdery mass at maturity, and 
the production on germination, of a whorl of secondary 
spores at the tip of the promycelium. 
Entyloma agrees in having free spores, and in the mode of 
germination, but the spores do not form a dry, powdery 
mass when mature. 
In Urocystis the spore-mass is dry and powdery when 
mature, but the fertile spores are in small clusters, which 
are surrounded by colourless, sterile cells. 
