elatinous or cartilaginous. The form of
the plant is usually very much contorted, fold-like or leaf-like, and
very much branched. The fruiting surface extends over the entire upper
surface of the plant.

[Illustration: FIGURE 205.--Tremella mycetophila, on Collybia dryophila
(natural size).]

=Tremella lutescens= Pers.--This plant is entirely yellow, and occurs on
branches. It is 2--5 cm. in diameter, and is strongly folded, somewhat
like the folds of a brain (gyrose). It is very soft and inclined to be
watery and fluid, and is of a bright yellow color, spread out on the
surface of rotten wood. It is of world-wide distribution, and appears
from mid-summer to late autumn.

=Tremella mycetophila= Pk.--This plant is interesting from the fact that
it is parasitic on a mushroom, _Collybia dryophila_. It grows on the
stem or on the top of the cap of the _Collybia_, and it is white, or
yellowish, very much contorted (gyrose-plicate), nearly rounded, and
8--16 mm. in diameter. Figure 205 represents this _Tremella_ growing on
the _Collybia dryophila_, from plants collected at Freeville woods near
Ithaca.

[Illustration: FIGURE 206.--Tremella frondosa. Pinkish yellow or pinkish
vinaceous (natural size). Copyright.]

=Tremella frondosa= Fr.--This is said to be the largest species of the
genus. It grows on rotten wood. It occurs in Europe, has been collected
in New York State, and the Fig. 206 is from a plant (No. 4339, C. U.
herbarium) collected at Blowing Rock, N. C., in September, 1899. The
plant figured here was 10 cm. long and about 8 cm. high. It is very much
twisted and contorted, leaf-like, and the middle and base all united. It
is of a pinkish yellow color, one plant being vinaceous pink and
another cream buff in color. When young the leaf-like lobes do not show
well, but as it expands they become very prominent.

Several other species of Tremella are probably more common than the ones
illustrated here. One of the commonest of the _Tremellineae_ probably is
the =Exidia glandulosa=, which in dry weather appears as a black
incrustation on dead limbs, but during rains it swells up into a large,
black, very soft, gelatinous mass. It is commonly found on fallen limbs
of oak, and occurs from autumn until late spring. It is sometimes called
"witch's butter."

[Illustration: FIGURE 207.--Tremella fuciformis. Entirely white (natural
size). Copyright.]

=Tremella fuciformis= Berk.--This is a very beautiful white tremella