gher forms of tissue and organisation
which are met with elsewhere. This division includes the lichens,
sea-weeds, confervae (green aquatic scum), fungi (mushrooms, dry-rot),
&c.

The division of _Vascular_ plants includes the far larger proportion of
vegetation, both living and fossil, and these plants are built up of
vessels and tissues of various shapes and character.

All plants are divided into (1) Cryptogams, or Flowerless, such as
mosses, ferns, equisetums, and (2) Phanerogams, or Flowering. Flowering
plants are again divided into those with naked seeds, as the conifers and
cycads (gymnosperms), and those whose seeds are enclosed in vessels, or
ovaries (angiosperms).

Angiosperms are again divided into the monocotyledons, as the palms, and
dicotyledons, which include most European trees.

Thus:--

-------------------------------------------------------------------
| (M.A. Brongniart). | |(Lindley). |
|CELLULAR | | |
| _Cryptogams_ (Flowerless) |Fungi, seaweeds, |Thallogens |
| | lichens | |
| | | |
|VASCULAR | | |
| _Cryptogams_ (Flowerless) |Ferns, equisetums, |Acrogens |
| | mosses, lycopodiums| |
| _Phanerogams_ (Flowering) | | |
| Gymnosperms (having |Conifers and |Gymnogens |
| naked seeds) | cycads | |
| Two or more Cotyledons | | |
| Angiosperms (having | | |
| enclosed seeds) | | |
| Monocotyledons |Palms, lilies, |Endogens |
| | grasses | |
| Dicotyledons |Most European |Exogens |
| | trees and shrubs | |
-------------------------------------------------------------------

Adolphe Brongniart termed the coal era the "Age of Acrogens," because, as
we shall see, of the great predominance in those times of vascular
cryptogamic plants, known in Dr Lindley's nomenclature as "Acrogens."

[Illustration: FIG. 10.--_Spenophyllum cuneifolium._ Coal-shale.]