Notes and Comments. 
181 
Society of London continues its stupid policy of issuing the 
* List of Literature ' (for 1921), without a subject index. It 
is little better than waste paper to any geologist worthy of the 
name. The list of abbreviations printed on pp. i-iii is ab- 
solutely inane. Does the council really think the Fellows are 
so childish as to need telling what ‘ Geol./ f glac.,’ ‘ Ital./ 
‘ Mag./ * U.S./ and scores of other simple abbreviations stand 
for ? We offer our sympathies to Professor Seward on his 
chaotic inheritance, and hope he will be able to repair, while 
in office, some of the ruin that has been done. 
ORCHID MYCORRHIZA. 
This wonderful botanical phenomenon is clearly and 
scientifically explained by Capt. J. Ramsbottom, in a supple- 
ment to the Orchid Catalogue of Messrs. Charlesworth and Co. 
For nearly a century this cohabitation of fungus and flowering 
plant has been suspected. The lichen is not now regarded as 
a separate entity, but as a combination of fungal threads and 
algal cells. Monotropa Hypopitys* is another well-known 
example. In this case the rootlets of the plant are enveloped 
with fungal hyphse {mycorrhiza = fungus roots), which appear 
to contribute to the benefit of the host/, the parasite flourishing 
on the exudation of the host. This partnership or co-habitation 
has been termed symbiosis = living together. 
SYMBIOSIS. 
The fungus is able to subsist on the humus or organic 
material in the soil, whilst the host plant can only extract 
nourishment from the inorganic materials, gases, water and 
mineral matter, and it is found that these symbiotic conditions 
exist chiefly where the soil has a large humus content. 
Provisionally, these symbiotic Fungi are classified as endotropic 
—entirely within, as in the lichen, and ectotropic = entirely 
without, as in Hypopitys. This mode of life is pointed out 
as occurring in many of the higher plantsf. Salicacese, 
Cupuliferse, Abietinese, etc., and some of the mosses, ferns and 
Lycopods. It was observed by Prof. Weiss (1904), in fossil 
roots from the lower Coal Measurers, and recently the same 
association has been found in the fossil plants Hornea and 
Rhynia of the Devonian series. Special attention has been 
directed by the author to the action on Orchids. In the past 
* In 1880, the present writer, in company with the Rev. W. Fowler, 
M. Slater and W. West, gathered this plant on the Southport sand dunes ; 
it was then thought to be parasitic on the roots of certain trees, and the 
party spent some time trying to trace the connexion, but without result, 
f See The Naturalist, June, 1917, p. 191. 
1922 June 1 
