52 Transactions British Mycological Soctety. 
produce roots. Further it is in these families that typical sapro- 
phytic species occur (if we concede that the Pyrolaceae are 
saprophytic Ericaceae) : in fact the presence of fungi in the roots 
of saprophytes is so common (the apparent exception being 
Wullschlaegelia), that MacDougal regards these seed-plants as 
being “‘saprophytic symbionts*.’’ Without the necessary data 
it is doubly unsafe to theorise, but it suggests itself that in 
families adapted to a mycorrhizal habit there is a tendency for 
the seed to become dependent upon the fungus for successful 
germination, and there is a correspondingly greater production 
of seed. It has been customary to associate increasing sapro- 
phytism with the greater development of mycorrhizal fungus. 
May it not be rather that saprophytism has arisen by the mycor- 
rhizal fungus taking over some of the functions necessary in 
germination and relieving the flowering plant of the need of 
excessive food production for the developing seed and thus of 
the necessity for carbon assimilation? (The great amount of 
fungus in the roots of saprophytes militates against the idea 
that the root may be simply a lodging-place for the fungus to 
be at hand for germination and of no use in nutrition.) We see 
in Calluna an almost perfect device for the infection of the seed, 
and the fungus is generally distributed. The most general in- 
fection so far found in orchids is in Neottia, which, as has been 
pointed out above, is most comparable with Calluna. But 
Neottia is saprophytic. In chlorophyllous orchids it almost looks 
as if when the necessary stimulus is given for seed germination 
precautions are taken to prevent general infection, the primary 
root even being free. In orchids digestion of the endophyte 
may also be a means of preventing general infection (though in 
Neottia this property can be easily recognised). Does such a 
general infection as we get in Calluna ultimately lead to sapro- 
phytism of the type seen in the Pyrolaceae? Are the events 
described above in the germination of certain orchids an effort 
to prevent general invasion and the “perfect symbiosis’ of 
Neottia? ‘ 
LoLIum. 
A case which recalls to mind that of mycorrhiza—especially 
having regard to recent discoveries—is that of the grass Lolium. 
The fact that the grains of Lolium temulentum contain a layer 
of fungal hyphae situated between the aleurone layer and the 
fruit and seed coat was first demonstrated by Vogl in 1898, and 
since then has been many times investigated in different species 
* Johow (1889) places all the known saprophytic flowering plants in the 
six families Orchidaceae, Burmanniaceae, Triuridaceae, Piroleae, Monotropeae 
and Gentianaceae. (The Triuridaceae are a small family of tropical sapro- 
phytes with the two genera Sciaphila and Triuris and about forty species.) 
