. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. 314 LYCOPODIUM genera Lycopodinni (Fig. 179) and Selaginella (Fig. 180). Tlie Quilhvort (Isoetes lacitsiris, Fig. 178), which occurs submerged in mountain tarns, is a pecuhar member of this group, many of whose features recall those of the fossil Clubmosses (Lcpido- dendron and Sigillaria, Fig. 177). Fragments of the stems of the ffH'mer with, or often without, the leaves, are very conunon in the Coal Measures and are readily identified bj- their charac- teristic markings (Fig. g. The small spirally ar-
. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. 314 LYCOPODIUM genera Lycopodinni (Fig. 179) and Selaginella (Fig. 180). Tlie Quilhvort (Isoetes lacitsiris, Fig. 178), which occurs submerged in mountain tarns, is a pecuhar member of this group, many of whose features recall those of the fossil Clubmosses (Lcpido- dendron and Sigillaria, Fig. 177). Fragments of the stems of the ffH'mer with, or often without, the leaves, are very conunon in the Coal Measures and are readily identified bj- their charac- teristic markings (Fig. g. The small spirally ar- ranged leaves of Lyco- podiinn densely clothe the stems, \\-hich are either erect, as in the Fir Club- moss [L. sdago), or pros- trate, except for the cone-bearing shoots, as in the Bear's Foot [L. clavatum, Fig. 179, A) The stems, as well as the occasional adventitious roots, exhibit forked branching, and never contain more than a single stele,1 whose detailed structure is often some- what complex. The sessile leaves are attached bj' a broad cushion-like base, and are traversed by but a single median vein (big. 179, B) ; the same was the case in Lcpidodcndron, the persistent leaf-cushions affording the dis- tinctive markings above referred to. The British species of Lvcopodium are found in nmist ujiland pasture, except for /,. imittdcdiim, which occiu's in lowland bogs. 1 A .single stele was likewise found in LcpidoJeiidro}! where, however, it became enveloped by a broad zone of seeondary wood and Fig. 177.—Kestoration of various fossil Clubnrosses (Lepidodeiidroii and Sigillaria). (.'\fter Grand Kury.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Fritsch, Felix Eugene, 1879-; Salisbury, E. J. (Edward James), Sir, b. 1886. London, G. Bell and sons ltd.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectpl, booksubjectplants
