328 
EXTRACTS—NATURAL HISTORY. 
burst when ripe, scattering it in every direction. Wherever it falls upon the 
leaf it takes root, and the fungus spreads rapidly. 41 
The superficial mildew, which attacks 
rose-trees and many other flowering shrubs, 
is a kind of Uredo. This name, derived from 
uro to burn or scorch, is applied to those 
occasional discolorations of the surfaces of 
plants which were formerly attributed to 
blights, or injuries from the atmosphere, 
and which have the appearance of a brown 
powder. Uredo effusa (Fig. 42,) generally 
shows itself on the under sides of the leaves of Ros&ceae, and spreads rapidly. 
Uredo Rosas is another kind, which also attacks rose-trees. The fungus called 
Acrosporium moniliodes (Fig. 43,) con- 42 
sists of a number of globules attached 
to each other, which, when magnified, 
appear like the beads of a necklace, 
and in many cases are found stand¬ 
ing upright. When ripe, these globules 
fall, and, taking root, form fresh strings, 
or necklaces like the first. Sometimes 
little tufts of these gobules appear fixed 
to stalks, and, from some fancied resem¬ 
blance to the brushes used for sprinkling 
holy water, are called Aspergillus, (Fig. 44). The superficial mildew which in¬ 
fects the onion, and is fatal to that plant, is called Botrytis. Its name signifies a 
bunch of grapes; it is thus called from a fancied resemblance existing between that 
fruit and its clusters of little globular seeds and seed-vessels. The bean and pea 
have a superficial mildew, (Ur£do Fabae) which spreads along their leaves like 
white roots curiously interlaced. From these roots spring a number of branch¬ 
like shoots, each bearing a ball-like head, or brown berry, which when ripe, 
bursts, and discharges seed. 
(To be continued in our next.) 
