454 Harvey- Gibson . — Contributions to Knowledge of 
instructive to note that a complete series of transitions may- 
be obtained in the different species, with .S'. spinosa at one end 
of the series and a typical ‘ rhizophore ’ bearing type such as 
.S'. Martensii or S. Galeottei at the other. In spinosa it 
will be seen that the roots arise directly from the base of the 
stem which is itself exceedingly delicate. Indeed the root- 
system in this species is out of all proportion to the com- 
paratively massive and much branched aerial portion, and 
points to the important part which the lower prostrate 
branches play in absorption. S. spinosa is, indeed, largely 
saprophytic in habit. This characteristic is emphasized by 
the frequent occurrence of symbiotic fungal hyphae in the 
cortical cells of the root, as observed and figured by Bruch- 
mann. On two or three occasions I have seen evidence of the 
presence of these symbiotic hyphae in the creeping part of 
the stem also. In 5. oregana the roots spring not only from 
the base of the stem but also from the lower region generally, 
where the shoots are in contact with the tree on which this 
species is epiphytic. This basal origin of roots and absence 
of so-called rhizophores is characteristic of types where there 
is a short rhizomic part with numerous erect axes, e. g. 
S.grandis , 5. erythropus , 5. Vogelii , 5. Karsteniana , 5. haema - 
todes , &c., and of those species which show a dense tuft of 
aerial erect axes arising from a short rhizomic basis, e. g. 
wS. involvens , 5. pilifera , &c. In 5. Braunii and 5. Lyallii 
the basal part of the stem is longer and more in the nature 
of a rhizome, and the roots arise from the under side of the 
rhizome, branching at once in the soil. 
In forms like >S. Kraussiana , S. serpens , S. delicatissima, 
&c., the stem is procumbent, grows parallel with the ground 
and a short distance from it. In these cases the aerial portions 
of the root are necessarily longer, and it is to this aerial 
part that the term ‘ rhizophore ’ is applied. In 5. Galeottei , 
.S’, caulescens , 5. Martensii , &c., the stem is at first pro- 
cumbent and then becomes semi-erect. The roots have 
correspondingly short aerial regions below, but these become 
longer as the stems become more and more erect. From the 
