70 
which forms rather firm, black sori about the peduncles, on the di- 
visions of the perianth, etc., (Fig. i) was named Ustilago junci by 
Schweinitz, in his Synopsis of North American Fungi, No. 2,816. 
As in the preceding species, its mycelium persists within the diseased 
parts of the host, though it is usually less abundant in the pith. Out- 
side of the fibro-vascular bundles it becomes denser, forming a con- 
tinuous, gelatinous stroma, which is colorless except for a narrow, 
yellowish band near its outer edge (Fig. ^). The outermost cells of 
this stroma are uniformly fertile, so that its entire outer portion 
passes Into a mass of young spores that are gradually pushed out- 
ward as they mature (Figs. 2-3). At first the sori are covered by 
the epidermis, which renders them lead-colored. After its disap- 
pearance the mass of spores appears intensely black, and gradually 
crumbles away. The mature spores, as seen singly, are of a dark 
brown color and rather opaque. They are minutely granulated, 
irregularly rounded or ellipsoidal in form, and measure 12-15 
14-21//. 
In the successive production of spores from a fertile stroma, this 
species closely resembles the last. It is evidently referrible to the 
same genus, and should bear the name Cintractia junci (Schw;) It 
differs from the other species in the character of its spores, which 
are darker, more angular, often elongated and minutely roughened, 
as well as somewhat larger, and in possessing a nearly colorless 
stroma, the entire outer surface of which is sporiferous and destitute 
of the sterile rays characteristic of C axicola. 
Spores of C. junci germinate readily in water while fresh, each 
emitting a colorless filament 1.5;^ in diameter, which reaches a length 
of several millimetres within a few days in cell cultures. The re- 
fractive protoplasm which at first fills it passes toward the end as it 
grows, leaving the basal part emptv. The formation of sporidia on 
these threads has not been observed. Similar hyph^ which are to 
be found in abundance in the outer portion of sori that have been 
exposed to rain or allowed to remain damp in the press are pre- 
sumably of the same nature, though they have not been traced to the 
*■ *"^ -^ *• -* ~. ^ 
> species is found on /uncus tenuis in New York (Sartwell, 
jide Berkeley in Grevillea iii., p. 59 ; Howe, jide Peck in 22d Report 
on N. Y. Cabinet, p. 93), North Carolina (Curtis, Plants of N. C, p. 
123), Iowa (Bessey, Bulletin Iowa Agl. College, Nov., 1884, p. US! 
Arthur, /. c, p. 172) and Wisconsin (Trelease, Parasitic Fungi ot 
Wis '^"^ . . -- - . - , i_i^ .« 
spores. 
Ellis's North American Fungi, No. 290; and I have also collectea 
specimens in that State. As a rule, nearly every inflorescence wih 
be attacked on a given stool of the host, while other plants immedi- 
ately about it remain entirely free. 
Description of Plate l,— i. Inflorescence- of /w/2re^:r tenuis attacked by Ctn- 
tracha junci (Schw.); natural size. 2. Longitudinal section through the ^^^'^^^P 
of a smut sorus, in the peduncle of the same plant, showing the stroma and sp 
mass on either side of the nearly unaltered inner tissues of the plant Wf rma- 
Fragment of a cross-section through a similar sorus, showing the mode ot to 
tinn and maturation of the spores on the outside of the stroma (x400). 
