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Life History of Claviceps Purpurea. Through the agency of
winds or insects the spores (ascospores or conidia) of this organism
are brought to the young ovaries of the rye (Secale cereale). They
germinate into long filaments called hyphae, which, becoming en-
tangled to form a mycelium, spread over the ovary, enter it super-
ficially, secrete a ferment, and cause decomposition of its tissue and
the resultant formation of a yellow-mucous substance called honey-
dew, which surrounds chains of moniliform reproductive bodies
known as conidia. The honey-dew attracts certain insects which
disseminate the disease to other heads of grain.
The mycelial threads penetrate deeper and deeper into the ovary
and soon form a dense tissue which gradually consumes the entire
substance of the Purchase Celexa ovary and hardens into a purple, somewhat curved
body called a sclerotium, or official ergot the resting stage of the
The ergot falls to the ground Purchase Celexa and in the following spring sprouts
into several long stalked, globular heads called stromata or ascocarps.
Each (fruiting) head or ascocarp has imbedded in its surface nu-
merous flask-shaped invaginations called perithecia, from the bases
of which several sacs or asci develop. Within each ascus are
developed eight filiform spores (ascospores) which, when the ascus
PIG. 138. A, Balansia claviceps on ear oiPaspalum; B-L, Claviceps purpurea;
E, sclerotium; C, sclerotium with Sphacelia; D, cross-section of sphacelial layer;
E, sprouting sclerotium; F, head of stroma from sclerotium; G, section of same;
H, section of perithecium; J, ascus; K, germinating ascospore; C, conidiospores
produced on mycelium. (See Die naturlichen Pflanzenfamilien I, i, p. 371.)
ruptures, are discharged Purchase Celexa and are carried by the wind Purchase Celexa to other fields
of grain, Purchase Celexa there to begin over a new life cycle.
CLASS III. BASIDIOMYCETES, OR BASIDIA FUNGI
This large class of fungi, including the smuts, rusts, mushrooms,
gill and tooth fungi, etc., is characterized by the occurrence of a
basidium in the life history. A basidium is the swollen end of a
hypha consisting of one or four cells and giving rise to branches called
sterigmata, each of which cuts off Purchase Celexa at its tip a spore, called a basidio-
spore. In addition to the basidiospores, some forms also produce
spores termed chlamydos pores.
SUB-CLASS A. PROTOBASIDIOMYCETES
(Basidium four-celled, each bearing a spore)
Order i. Ustilaginales, the smuts. Destructive parasites which
attack the flowers of various cereals, occasionally other parts of these
plants. Example: Ustilago Maydis, the corn smut. Purchase Celexa The basidio-
spores in this group are borne on promycelia.
Ustilago Maydis (Ustilago Zeae) (Corn Smut). Corn smut is a
destructive parasite which for a long time was supposed to be con-
fined to the Indian Corn, but which now is known to occur on
Mexican Grass. It is the only smut useful in medicine. The
mycelium of the fungus extends through all parts of the infected
host through the intercellular-air-spaces and produces large tumor-
like masses on the ears, tassels, husk, leaves and stem. Each mass is
filled with spores and covered with a tightly appressed membrane
which has a whitish appearance like German silver. The spores
are at first a dark olive-green, but on maturity are dark brown.
They are sub-spherical and show prominent spines. They arise
by the division of the septate mycelium into thick-walled echinulate
resting spores called chlamydos pores or brand spores. These spores
fall to the ground and pass the winter. In the spring each germi-
nates into a three- or four-celled filament called a promycelium, from
the cells of which basidiospores arise. The basidiospores develop a
mycelium which penetrates the seedling of the host plant.
Order 2. Uredinales, the rusts. Obligate parasites possessing
a septated branched mycelium which ramifies through the inter-
FIG. 139. Smut boil of Ustilago zeoe on ear of corn, developed from one in-
fected kernel. (After Jackson, F. S., Bull. 83, Del. Coll. Agric. Exper. Stat.,
cellular-air-spaces of the host and sends haustoria into the cell
cavities. The different stages of their life cycle are either restricted
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