226 
MORPHOLOGY OF MEMBERS. 
but this leafy plant does not, as in the case of the Fern, produce spores, but can be 
reproduced by bulbils of different kinds. At length however, like the prothallium 
of Ferns, it produces sexual organs, and an embryo is the result of the fertilisation 
of the oosphere : this is not connected organically with the Moss-plant, but remains 
attached to it, deriving its nourishment from it, and finally developes into a capsule 
supported on a long stalk, the Sporogoniiim, in the interior of which are produced 
numbers of spores. A number of these stalked capsules, i. e. entire generations, 
may arise on the same Moss-plant either simultaneously or successively. The 
course of development of a Moss is therefore divided into two sharply separated 
stages, viz. the formation of a leafy stem which produces sexual organs (oophore), 
and the production of stalked capsules out of the fertilised oospheres of the female 
organs. In Muscineas the second or asexual generation (sporophore), the sporo- 
gonium, has no power of directly producing its like from itself, as is possible in 
the case of Ferns, by bulbils; its only function is to produce spores^; and when 
the spore germinates it gives rise first of all to a Protonema, which sometimes con- 
tinues to grow for a long while, and can reproduce itself by gemmae, until at lengh 
Moss-stems with true leaves again appear on it, which also are capable of multi- 
plication by means of bulbils. 
Even in Thallophytes we meet with various forms of an alternation of gene- 
rations I It is well shown in certain Fungi of the class Ascomycetes which have 
been closely investigated, as, for example, in the common mould, Penicillium 
glaiicum^ the ordinary form of which is only the first generation or stage of 
development in its life. During this stage, the first or sexual generation, the 
so-called Mycelium, developes on special branches a number of cells {cmidia), 
by which the Fungus is continually propagated in this form. But when the 
excessive development of these conidia is prevented by exclusion of the air^ 
sexual organs arise, as Brefeld has shown, on the luxuriant mycelium, and in 
consequence of their union a tuberous body is formed of a totally different 
nature, within which spores are finally produced in extremely numerous sacs 
{asci^ of peculiar form; and these, when they germinate, again produce the 
mycelium with its penicillate conidiophores. The mycelium of this Fungus 
(and strictly speaking of all Fungi) corresponds therefore to the first stage of 
development, the prothallium, of Ferns, or to the leafy Moss-plant; and all three may 
be considered as the Sexual Generation [oophore], since their normal development 
ends with the formation of sexual organs. In all three cases, this sexual gene- 
ration (prothallium, Moss-plant, mycelium) may propagate itself by gemmae or by 
conidia before it produces the sexual organs. The small tubers which are the result 
of fertilisation in Penicillium correspond to the second stage of development, viz. 
the sporogonium of Mosses, and the mature Fern-plant^; in all three cases the 
product of this second generation [sporophore] is a large number of spores, by 
^ [The researches of Pringsheim and Stahl however have shown that this limitation can no 
longer be maintained. See Book II. Group 2.] 
^ [This explanation is now no longer generally accepted ; see Journ. of Botany, 1879.] 
^ If these small tubers in Penicillium are termed the fructification, then in the same 
sense the sporogonium of Mosses is a fructification ; and the Fern is also the fructification of 
the prothallium. 
