382 CALAMITES. [CH. 



of forests of Calamites in the Coal-Measures of central France, 

 enable us to form some idea of the habit of growth of these 

 plants with their stout branching rhizomes and erect aerial 

 shoots. 



By piecing together the evidence derived from different 

 sources we may form some idea of the appearance of a living 

 Calamite. A stout branching rhizome ascended obliquely 

 or spread horizontally through sand or clay, with numerous 

 whorls or tufts of roots penetrating into swampy soil. From 

 the underground rhizome strong erect branches grew up as 

 columnar stems to a height of fifty feet or more ; in the lower 

 and thicker portions the bark was fissured and somewhat 

 rugged, but smoother nearer the summit. Looking up the 

 stem we should see old and partially obliterated scars marking 

 the position of a ring of lateral branches, and at a higher level 

 tiers of branches given off at regular or gradually decreasing 

 intervals, bearing on their upper portions graceful green 

 branchlets with whorls of narrow linear leaves. On the 

 younger parts of the main shoot rings of long and narrow 

 leaves were borne at short intervals, several leaf-circles suc- 

 ceeding one another in the intervals between each radiating 

 series of branches. On some of the leaf-bearing branchlets 

 long and slender cones would be found here and there taking 

 the place of the ordinary leafy twigs. Passing to the apical 

 region of the stem the lateral branches given off at a less and 

 less angle would appear more crowded, and at the actual 

 tips there would be a crowded succession of leaf-segments 

 forming a series of overlapping circles of narrow sheaths with 

 thin slender teeth bending over the apex of the tree. 



Thus we may feebly attempt to picture to ourselves one of 

 the many types of Calamite trees in a Palaeozoic forest, growing 

 in a swampy marsh or on gently sloping ground on the shores 

 of an inland sea, into which running water carried its burden of 

 sand and mud, and broken twigs of Calamites and other trees 

 vsrhich contributed to the Coal Period sediments. The large 

 proportions of a Calamite tree are strikingly illustrated by 

 some of the broad and long pith-casts occasionally seen in 

 Museums ; in the Breslau Collection there is a cast of a stem 



