186 BOTANICAL GAZETTE. | August, 
are called by Van Tieghem facultative parasites may live 
ordinarily as saprophytes and yet at times live a truly para- 
sitic existence. The great majority of fungi are saprophytes, 
and De Bary has shown’ in an instructive way how Peziza 
sclerotiorum, during a part of its existence, is a saprophyte, 
and becomes later a true parasite. The germinating spores 
will not penetrate the living cells of the carrot on which the 
mature forms of the fungus is found, but live a saprophytic 
existence for some time. After they have attained a certain 
growth and strength they are then able to make their way 
into the carrot, which they destroy. The mechanism is as 
follows: after a certain time the saprophytic hyphae excrete 
an oxalate which is able to destroy the superficial cells of the 
carrot with which the hyphae may come in contact, and the 
fungus then makes its way into the plant. It is probable that 
a considerable number of saprophytes may: act in the same 
way as Peziza sclerotiorum, and it is not impossible that a 
good many existing saprophytes are developing into para- 
sites,-and, if the present state of things correctly represents 
what has always been going on, it would lead us to believe 
that the saprophytes first came into existence and the para- 
sites followed. Since actual knowledge is out of the ques- 
tion, one can take either theory without denying the other 
a toto. ‘The probabilities seem to me to favor the origin of 
Chytridia from Protococci, if we regard the morphological 
rather than the physiological side of the question. How far 
the first Chytridia were true parasites rather than sapro- 
phytes may be questioned. Decidedly, the majority of the 
living species, I should say, are parasites ; but in some the 
parasitism 1s not well marked, and they may be conveniently 
called epiphytic. 
not suppose that the first living beings were protoplasmic 
‘bodies, neither plants nor animals, or both, if you please 
and from them parasitic and non-parasitic plants were SIM° 
like Myxomycetes might 
cetes are plants at all. If they are plants, they have re- 
mained in a low condition, and have no offshoots represented 
by higher forms of plants. There appears to be only one 
way to find out whether a given structure is a plant or a? 
animal, and that is to see whether it is described in 200108" 
Oe ee 
? Bot. Zeit., 1886, 
. 
