CLAVICEPS.— PEZIZA. 384 
(fig. 841) or ergot, which is ultimately (fig. 843) a somewhat 
horn-shaped body of a dark purple colour, is formed. 
After remaining dormant during the winter, the Ergot or 
Sclerotiwm produces spores (from which the sphacelia can again 
be formed) in the following manner. Stalked receptacles ( Sig. 
843) grow up from the tissue of the Ergot, in which are deve- 
loped a number of perithecia (fig. 844). These perithecia are 
somewhat flask-shaped cavities (fig. 845), which are filled with 
asci ; the latter containing long slender spores ( Jig. 846), termed 
ascospores, which again, by germinating on the Rye or allied 
Grasses, give rise to the sphacelia. 
Pexiza, our second example of the Ascomycetes, is a genus 
of Fungi containing a great number of species, many of which 
Fic. 845. Fie. 846. 
Fig. 845. A single perithecinm of Claviceps purpurea, magnified, showing the 
contained asci. After Tulasne. Fig. 846. Asci of the same, containing 
the long slender ascospores. After Tulasne. 
are very common, and may be seen growing upon the dead 
trunks of trees, &c. Peziza is recognised as a small disc- 
shaped body, slightly cupped on the upper surface and of a 
reddish-purple colour. On close examination it is found that 
this structure (which is in fact the fructification) is growing 
from, and continuous with, a mycelium vegetating under the 
surface of the wood, &c., upon which the Fungus is situated. 
On examining a vertical section under the microscope, it is seen 
to consist of numbers of elongated cells closely packed side by 
side. Of these the greater number are very narrow and some- 
what club-shaped at the extremities, whilst the others are 
broader (fig. 847, a-f) and each contains eight oval spores in a 
greater or less state of development. These latter cells are 
known as the asci (the spores they produce being termed asco- 
co 
