[MATTHEW] UPPER DEVONIAN PLANTS 111 



Systematic position of Bothrodendron. 



"Bothrodendraceae is a small group (of plants) intermediate 

 between Lepidodendraceae and Sigilliariacese. Records show that 

 Bothrodendron (i.e. Cydostigma) was at its maximum in the Devonian 

 epoch, Lepidodendron in the Lower Coal Measures and Sigillaria in 

 the Middle Coal Measures. F. E. Weiss places Bothrodendron. as a 

 sub-genus of Sigillaria. In the "Pre-Culmian" in the Harz Mts., etc., 

 Bothrodendron (Cydostigma, &c) is present, but Lepidodendron 

 absent or sparingly present. The general evidence seems to show 

 that Bothrodendron {i.e. Cydostigma, etc) is an earlier type than 

 Lepidodendron and both Sigillaria and the latter are derivable from 

 the former. Young shoots of Bothrodendron (Cydostigma, &c) are 

 very like those of Lepidodendron. 



Summary. 



"The stem of B. (C) Kiltorkense was 8 metres in length by 30 

 centimetres in width (26 feet by 1 foot). It branched frequently and 

 dichotomously, and the leaves formed apical tufts. They were long, 

 linear and subulately pointed, and were early deciduous. A single 

 median bundle runs the whole length of the leaf. The leaves were 

 clearly arranged in w^horls at first, but become distant and quincun- 

 cially arranged on the older stems, owing to the unequal extension 

 of the stem surface.^ 



"The leaf scars are always small (very small G.F.M.) and papil- 

 late at first, but become flush with the stem surface later on, or even 

 sunken a little below it. Sometimes the papilla are quite pronounced 

 on the older stems. On well preserved stems the leaf scar shows the 

 usual lepidophyte marks or citricule, but the ligular scar is difficult 

 often impossible to observe with certainty.- The shape of the leaf 

 scar changes with age; in the young shoot it is circular — triangular with 

 the apex directed upward, and in older shoots, subcircular in outline, 

 with a projecting ring-like border, pronounced below and passing off 

 upward into a sloping ledge which may be regarded as part of the leaf 

 cushion. 



Markings of the Stem Surface; Plate IV, Fig. L 



"The stem shows a finely, longitudinally striate surface or epi- 

 dermis; the direction of the striae being disturbed by leaf-scar posi- 

 tions. In addition the stem may show a marked fluting or ribbing 



'On the narrow distal branches of the stem, the leaf scars appear at long intervals 

 and without any regular order. G.F.M. 



^I have not been able to detect it. G.F.M. 



