XXXII] CALAMOPITYS 191 



family-name Calamopityeae and recognised a close anatomical 

 affinity between Calamopitys and Lyginopteris, a conclusion which 

 led to the incorporation of Unger's genus in the Pteridosperms. 

 Further data have been supplied by Zalessky 1 and, more recently, 

 by Scott and Jeffrey 2 who have recognised Calamopitys in Lower 

 Carboniferous beds in Kentucky. 



Calamopitys Saturni Unger. 



Our knowledge of this and other species is confined to stems 

 and petioles. One of the largest examples of the species is a 

 piece of stem with a diameter of 1-5 cm. : the single stele consists 

 of a parenchymatous pith enclosed by secondary xylem made 

 up of tracheids with 4 8 rows of bordered pits and medullary 



FIG. 454. Calamopitys Saturni. B, stem with leaf -base; x, primary xylem 

 and pith; black patches represent leaf -traces; C, stem with two leaf -bases; 

 D, section of petiole. (After Solms-Laubach.) 



rays more than one cell broad and of considerable depth. Between 

 the inner edge of the wood and the pith are groups of primary 

 xylem (fig. 454, B, x) which, like those in Lyginopteris, constitute 

 the leaf -traces : each has a single internal protoxylem strand 

 (fig. 455, B). The comparatively wide cortex consists of paren- 

 chyma with a hypoderm of the Sparganum type. Each primary 

 xylem-strand passes out as a single leaf-trace through the secondary 

 xylem and on emerging divides into two as in Lyginopteris : these 

 branch in the cortex and the two are replaced by six in the 

 leaf-base (fig. 454, B D). As seen in figs. 454, C, 455, A, the 

 boundary between the stem proper and the decurrent leaf-base 

 is marked by a line of stereome strands. The petioles of Calamo- 

 1 Zalessky (11). 2 Scott and Jeffrey (14). 



