Phloem.—Commonly called “bast”. The elongated vessel-like cells which conduct the manufactured food. See [p. 57].
Pollen Chamber.—The cavity inside a Gymnosperm seed in which the pollen grains rest for some time before giving out the male cells which fertilize the egg-cell in the seed. See [p. 76].
Polystelic.—A type of stem that appears, in any transverse section, to contain several steles. See note on the use of the word on [p. 63].
Protoplasm.—The colourless, constantly moving mass of finely granulated, jelly-like substance, which is the essentially living part of both plants and animals.
Rock.—Used by a geologist for all kinds of earth layers. Clay, and even gravel, are “rocks” in a geological sense.
Roof, of a coal seam. The layers of rock—usually shale, limestone, or sandstone—which lie just above the coal. See [p. 24].
Sclerenchyma.—Cells with very thick walls, specially modified for strengthening the tissues. See [fig. 28], [p. 56].
Seed.—Essentially consisting of a young embryo and the tissues round it, which are enclosed in a double coat. See definition of “Fruit”.
Shale.—A fine-grained soft rock, formed of dried and pressed mud or silt, which tends to split into thin sheets, on the surface of which fossils are often found.
Species.—Individuals which in all essentials are identical are said to be of the same species. As there are many variations which are not essential, it is sometimes far from easy to draw the boundary between actual species. The specific name comes after that of the genus, e.g. Pinus montana is a species of the genus Pinus, as is also Pinus sylvestris. See “Genus”.