The vegetation is still simple in its development, for forest-trees seem altogether wanting. The Asterophyllites, with tall and slender stems, rise singly to a considerable height. Cryptogams, of which our mushrooms convey some idea, would form the chief part of this primitive vegetation; but in consequence of the softness of their tissues, their want of consistence, and the absence of much woody fibre, these earlier plants have come down to us only in a fragmentary state. [Illustration: IX.--Ideal Landscape of the Devonian Period.] The plants belonging to the Devonian period differ much from the vegetation of the present day. They resembled both mosses and lycopods, which are flowerless cryptogamic plants of a low organisation. The Lycopods are herbaceous plants, playing only a secondary part in the vegetation of the globe; but in the earlier ages of organic creation they were the predominant forms in the vegetable kingdom, both as to individual size and the number and variety of their species. [Illustration: Fig. 30.--Plants of the Devonian Epoch. 1. Algæ. 2. Zostera. 3. Psilophyton, natural size.] In the woodcut (Fig. 30) we have represented three species of aquatic plants belonging to the Devonian period; they are--1, _Fucoids_ (or _Algæ_); 2, _Zostera_; 3, _Psilophyton_. The Fucoid closely resembles its modern ally; but with the first indications of terrestrial vegetation we pass from the _Thallogens_, to which the _Algæ_ belong (plants of simple organisation, without flower or stem), to the _Acrogens_, which throw out their leaves and branches at the extremity, and bear in the axils of their leaves minute circular cases, which form the receptacles of their spore-like seeds. “If we stand,” says Hugh Miller, “on the outer edge of one of those iron-bound shores of the Western Highlands, where rock and skerries are crowned with sea-weeds; the long cylindrical lines of _chorda-filum_, many feet in length, lying aslant in the tideway; long shaggy bunches of _Fucus serratus_ and _F. nodosus_ drooping from the sides of the rock; the flat ledges bristling with the stiff cartilaginous many-cleft fronds of at least two species of _Chondrus_; now, in the thickly-spread Fucoids of this Highland scene we have a not very improbable representation of the Thallogenous vegetation. If we add to this rocky tract, so rich in Fucoids, a submarine meadow of pale shelly sand, covered by a deep-green swathe of _Zosteræ_, with jointed root and slim flowers, unfurnished with petals, it would be more representative still.” Let us now take a glance at the animals belonging to this period.