THE FUNGI 401 
comes on, an examination of stubble in the field (blades of grass 
and stems of wheat left carelessly), shows that these rust-red 
lines are replaced by brownish-black ‘spores called teleutospores 
(teliospores). A mass of these is known as a telium. 
The summer stage on wheat is known as Uredo linearis. 
The autumn stage on wheat is known as Puccinia graminis. 
The teleutospores are two-celled and have thick walls and 
persistent pedicels. They remain attached to the stubble until 
the following spring and then either one or both cells composing 
_them produce an outgrowth known as a promycelium (nothing but 
a basidium divided transversely into four cells). Each cell of the 
basidium is capable of producing a branch, at the tip of which 
a basidiospore is formed. ‘These basidiospores are blown to 
the Barberry (Berberis) and infect the leaves of this plant. The 
mycelium runs in the intercellular-air-spaces and causes the ~ 
appearance of a number of small depressions on the upper side 
of the leaf. These in section are a rich chocolate brown and 
known as spermagonia. In the center of a spermagonium are 
produced hyphz, which project out to its orifice and obstrict 
off minute spores called spermacia. On the opposite side of the 
leaf, cup-shaped depressions are formed, each with a limiting 
membrane (feridium). Within the cup-shaped depression thou- 
sands of spores are formed in chains closely packed together. 
These are the acidiospores (aciospores). The cluster cup is called 
an Atcidium (Aicium). These zciospores are conveyed to wheat 
and cause infection, thus completing the life cycle. It has been 
observed that in America the uredospores or summer spores may 
_ winter over and infect healthy plants, so that the Barberry 
phase is completely eliminated from the life cycle. 
Some OTHER Rusts.—The White Pine Blister Rust, 
Cronartium ribicola, causes great damage yearly to the Pinus 
strobus and other 5-needle pines. It has its aecial and spermatial 
stages on these pines and the uredospore and teleutospore stages 
on currants (Ribes spp.). The Hollyhock Rust, Puccinia mal- 
vacearum occurs on the hollyhock (Malva rosea) and other species 
of Malva, notably the drug-yielding Malva rotundifolia and M. 
sylvestris. It passes through two stages, the teleutospore and 
basidiospore, on the same host, only a single host being involved. 
