GLOSSARY 317 
RECURVATUS (recurvare = to bend backwards). Curved 
back. 
REFLEXED (reflectere = to bend back). Bent back. 
REPENS (Lat. repere = to creep). Applied to creeping 
plants. 
REsIN CaNnaLs or REsin Ducts. Intercellular spaces running 
parallel with the stem and through the leaf. In a trans- 
verse section of the leaf they take the form of a circular 
opening which is visible under a magnifying glass, or can 
be sometimes sufficiently made out by squeezing the 
leaf after it has been cut across, when the resin can be 
discerned exuding from the ducts. They are differently 
placed and vary in number in different trees. Some- 
times they are situated close to the edge or the epidermis 
of the section of leaf, and then are described as marginal. 
In other trees they are placed about half-way between the 
centre of the leaf (where the fibro-vascular bundle is 
seen), and the outside edge, when they are described 
asmedian. For example, the resin canals in the Common 
Silver Fir are two in number and marginally placed. In 
the Douglas Fir the same, while the P. Laricio (Corsican 
and Austrian) have eight medianly placed resin ducts. 
The Hemlock spruces have only one placed close to, and 
immediately under, the fibro-vascular bundle. In the 
Ternate (3-in-a-bundle) Pines and the Quine (5-in-a- 
bundle) the resin canals are usually fewer. . 
These are some of the more minute characteristics of conifers 
that ought to be studied in the transverse section under 
magnifying glasses. 
RETICULATUS (reticulum = a little net). With small inter- 
secting lines like the meshes of a net. 
REVOLUTE (re = back ; volvere = to roll). Rolled back out 
of the ordinary direction. 
RuyomBorp (Gk. rhembein = to turn round and round). An 
imperfect oval-shaped figure and angular at the middle, 
and so a form more or less diamond-shaped. 
ScaLes. An expression connected with the word Shell, and 
used to denote the scales or thin layers and coverings of 
a fish or reptile. Applied botanically to the encrusted 
covering of leaf buds and cones, 
