220 Mat' shall Ward. — Illustrations of the Structure 
forthwith, these teleutospores need to be kept for some time 
before they will germinate. In the usual case they are scat- 
tered with the straw, and germinate in the following spring. 
(Zeiss E.) 
Fig. 7. Four teleutospores germinating. The one to the 
left and that to the right had been kept for three years in my 
laboratory, and germinated as seen after lying for three days 
in water on glass. The two middle specimens, left uncoloured, 
were six months old. The process of germination consists in 
the erosion of the thick exosporium from within, the contents 
enveloped by the endosporium dissolving their way through at 
some one point ; both cells may germinate, or one only. The 
germ-tube grows to a short and often curved (or longer 
and straighter) pro-mycelium , which gradually acquires all the 
contents of the cell of the teleutospore, except perhaps a 
few granules and an oily drop or two. This pro-mycelium 
then becomes segmented into four or five (occasionally three) 
one-celled joints by transverse walls. Each cell of the pro- 
mycelium then puts forth a short delicate branch, sterigma , 
much thinner than itself, and the tips of this sterigma slowly 
swells up into a spheroidal vesicle, sporidium , which takes up 
all or nearly all the protoplasm ; occasionally the sterigma 
branches and more than one sporidium is formed. These 
sporidia are very minute, as may be seen by comparing Figs. 
5 and 7. All attempts to cultivate them on wheat have 
failed, and De Bary discovered the remarkable fact that they 
develop successfully only on the barberry. 
Fig. 8. Three of the sporidia germinating in water on glass. 
(Zeiss E.) 
Fig. 9. This preparation is taken from De Bary, and repre- 
sents three of the sporidia germinating on the epidermis of 
the barberry-leaf, and sending their germ-tubes through the 
cuticle into the plant below. In the leaf of the barberry, 
the mycelium developed from these tubes ramifies between 
the parenchyma cells, as septate branched hyphae, with 
orange-red granules in the protoplasm (see Fig. 10 a), and 
eventually produces the form known as Aecidium Berberidis. 
