328 MR ROBERT KIDSTON ON THE 



orifices of two secreting glands which are placed beneath the bark. These glands pro- 

 bably fulfilled their secreting function (whatever the nature of the secretion may have 

 been) after the fall of the leaf, and throughout the whole life of the plant, and considering 

 the great number of such glands on each plant of Sigillaria, Renault throws out the 

 suggestion that perhaps it might be asked if the secretion from these glands does not 

 form a large part of the inorganic matter found in coal.'" 



The faint striations on the surface of the stem drawn at fig. 11 are caused by the 

 striatums on the subepidermal surface, which have been imparted to the outer surface 

 by pressure. 



Horizon : — In Blue Bind at a depth of 533 yards.t 



Sigillaria mamillaris, Brongt. 

 Fig. 10. 



Sigillaria mamillaris, Brongt., Hist. d. veget. foss., p. 457, pi. cxlix. fig. 1 ; pi. clxiii. fig. 1 (var. 



intermedia). 

 Sigillaria mamillaris, Goldenberg, Flora Sarsep. foss., Heft ii. p. 32, pi. viii. figs. 6-8 (fig. 8, var. 



intermedia). 

 Sigillaria mamillaris, Weiss, Foss. Flora d.jiingst. Stk. u. d. Bothl., p. 164, pi. xv. figs. 1-4 (figs. 1, 2, 



var. abbreviata, fig. 4, var. elongata). 

 Sigillaria mamillaris, Zeiller, Flore foss. du bassin hoidller de Valenciennes, pi. lxxxvii. figs. 5-10. 

 Sigillaria pyriformis, Brongt., Hist. d. veget. foss., p. 448, pi. cliii. figs. 3, 4. 



Description. — Ribs straight or slightly flexuous, separated by a well-defined furrow. 

 Leaf scars hexagonal or pyriform-hexagonal, as broad as long, or longer than broad, 

 lateral angles distinct (especially in the forms with hexagonal leaf scars.) The surface, 

 of the leaf scar is elevated from above downwards, so that the inferior margin stands at 

 a higher level than the superior margin ; the interfoliar portion of the ribs immediately 

 below the leaf scar slopes downwards, the leaf scar is thus placed on the upper slope of an 

 elevated cushion. Vascular cicatricule punctiform or slightly elongated transversely, 

 lateral cicatricules lunate-elongate. Leaf scars somewhat close or more distant. The 

 interfoliar portion of the cushion on which the leaf scars sit, bears two lines of transverse 

 wrinkles, between which the wrinkles frequently extend, and thus cover the whole of 

 the interfoliar portion of the cushion. Above the leaf scars is a well-defined arched 

 transverse furrow. 



Cone scars, quadrate or irregular-triangular, with a central subcircular cicatrice, 

 situated on the ribs, and forming a verticil of several series. 



Decorticated stem striated longitudinally, and showing the three cicatricules, the 

 lateral cicatricules almost straight or occasionally lunate and united at their extremities, 

 thus forming a circle surrounding the vascular cicatricule. 



* Renault, " Sur les cicatrices des Syringodendron," Comptes Bendus, 24th October 1887. 



t The lateral cicatricules in the leaf scars of Lepidodendron, Lepidophloios, and Bothrodendron, probably performed 

 the same function. When the structure of these lateral cicatricules is examined, they never show any trace of vascular 

 tissue, but are filled with lax parenchyma. A good figure of their structure is given by Dr Felix (Untersuchungen 

 fiber den Bau weslfalischer carbon Pflanzen, pi. ii. fig. 3/, Konig Preusseschen geol. Landesanslalt, 1886. 



