XXIV 
INTRODUCTION. 
spores and teleutospores on another quite different species of 
host plant, let us say, on wheat or barley. This is the con- 
tention, but it is not our intention to argue the question here, 
merely to state the assumption. 
Then there is another group in which only the spermogonia, 1 , 
uredospores, and teleutospores are known, and these all occur 
on the same host plant. Here the recidiospores are absent. 
In a fourth group only the secidiospores and teleutospores 
are known, and these occur on the same species of host plant. 
The uredospores are wanting, or if not absolutely wanting they 
are only found mixed with the teleutospores, and do not form 
pustules of their own. 
In the fifth group teleutospores only are known, so that both 
fecidiospores and uredospores are absent, and the teleutospores 
only germinate after a period of rest. In another group, which 
is little more than a sub-section, teleutospores only are known, 
but they germinate at once upon arriving at maturity, without 
any period of rest. Thus far, then, we have set out briefly the 
grouping adopted by those who have devoted themselves most 
actively to the study of Puccinia and its allies. A somewhat 
similar grouping is adopted for TJromyces. Our object has been 
to illustrate wherefore, in the descriptions of some species of 
Puccinia, we have spermogonia, mcidiospores, uredospores, and 
teleutospores all described as parts of the same whole, whereas 
in other descriptions only some of these are to be found. 
There are two or three small groups still remaining, to which 
we have made no allusion, although they possess an interest of 
their own. One of the most noteworthy of these is the Phyco- 
mycetes, as represented in this “Handbook,” but an amplifica- 
tion of the limits of that group as previously entertained. In 
this idea we have followed Mr. Massee, in his recent volume, 
“British Fungi, Phycomycetes,” etc. The old limitation con- 
fined the species to the type of Nucor, having the habit of 
moulds, but with spores enclosed within a sporangium, instead 
of being produced naked, at the tips of branches. In this 
aspect the group was assumed to have some relationship to the 
Ascomycetes , in the compound fructification. As here repre- 
sented, they consist of fungi having a mycelium typically 
devoid of septa, and parasitic on living plants or animals, or 
growing upon dead organic substances. Having sexual repro- 
duction by means of oogonia and antheridia, or by the conjuga- 
tion of similar branches, and an asexual mode of reproduction 
by means of gonidia, or zoogonidia. The value of the different 
sections may be gathered from the following arrangement : 
A. Threads well developed. 
Threads producing sporangia. Asexual reproduction by gonidia 
i developed in sporangia ; sexual by zygospores . . . Mucoraceee. 
Threads frequently branched, bearing zoogonidia, or passive gonidia. 
Asexual organs gonidia ; sexual, oospores . . Peroiio &p o vetoetp . 
