RUSTS. 
325 
This golden visitation, unwelcome as it is, may afford a sub- 
ject for the microscope, and for a small space in my paper. 
At first there will not appear to be any important difference 
between the spores of the yellow series of the last genus and 
those of the present ; but a closer examination will reveal one 
important distinction ; viz., the presence of colourless elon- 
gated, abortive spores. The species are not so numerous by 
half as those of Trichobasis , even when three anomalous forms 
are included, which species are included by some mycologists 
in two other genera. One very common rust of this group 
has already been alluded to (Plate VIII. fig. 9), and which is 
known botanically as Lecythea Rosce. A similar one is found 
on the bramble, and another on the burnet. All these three 
species are produced at first on spots which are afterwards 
more or less occupied by the long, many-celled spores of the 
dark brown brands called Aregma or Phragmidium, between 
which and the simple yellow spores of the rust almost every 
intermediate form may often be found in the same pustule. 
Thus, from the same mycelium as that of the rose rust, the 
rose brand is afterwards developed ; whilst from the nidus of 
the bramble rust (Plate VIII. fig. 11) the bramble brand is 
also at length produced ; and the successor to the burnet rust 
(Plate VIII. fig. 4) is the burnet brand. Besides these, a rust 
belonging to the same genus may be found on the leaves of 
the poplar, the spurge, and the common valerian, and two or 
three species on willows. It can scarcely have escaped notice, 
that the goat-willow is almost constantly afflicted with a rust 
on the under surface of the leaves (Plate XIII. fig. 1). This 
species will again come under notice in a later portion of 
this paper, as the summer spores of a truly di-morphous 
species. 
One of the rusts separated by some botanists from this 
genus, is found (possibly most commonly) on the leaves of the 
raspberry ; but during” the past autumn I have met with it 
plentifully on the upper surface of the leaves of one or two 
species of bramble, ' and have never seen it growing on the 
raspberry, although in all descriptions of the species that is 
stated to be its habitat. Even to the naked eye this is so 
distinct, that no one could well confound it with any other. It 
appears very late in the autumn, and the spots are scattered 
at some distance apart from each other (Plate XIII. fig. 3) ; 
each spot or pustule forming a ring (fig. 4 enlarged) encircling 
a cluster of spermogones which occupy the centre. 
Another rejected species (. Lecytliea Lini, Lev.) occurs on the 
little purging flax ( Linum catharticum) , forming small pustules 
on the leaves (Plate XIII. fig. 6 ) ; these burst irregularly, and 
remain surrounded by the remains of the ruptured epidermis 
vol. hi. — NO. xi. z 
