MORPHOLOGIC FEATURIJS 



21 



Fig. 4. — Segment of peduncle of (?) Mazocarpon oedipternum. Drawing was prepared from 

 a peel taken simultaneously from tangential and transverse surfaces as shown. Proto- and 

 metaxylem of stele shown in black; medullary tissue lined; cortical tissue stippled. Steles are 

 separately drawn at higher magnification at the left to show protoxylem points. From C. B. 136 

 A5 (17). 



The^ peduncle of a cone is illustrated 

 on plate 6, figure 2, and in text figure 

 4. The axis illustrated was not found 

 attached to a cone but the close simil- 

 arity of its stelar structure to that of 

 less well preserved but attached ped- 

 uncles permits little doubt as to its re- 

 lation. The stele of another peduncle 

 is shown at greater magnification on 

 plate 6, figure 1. Were it not for the 

 stelar similarity, there might be some 

 doubt as to the identification of the ped- 

 uncle because of differences in the cor- 

 tical tissue. The cortical tissue is rather 

 thick at the position illustrated by figure 

 2 and shows prominent parichnoidal 

 cavities. Adjacent to the cone, how- 

 ever, there seems to be a definite transi- 

 tion to the structure of the cone axis; 

 the peduncle is smaller than in figure 

 2, has no bracts, and the outer surface 

 is quite regular. At this higher position 

 close to the cone, sclerenchyma is pres- 

 ent around the periphery which presum- 

 ably merges proximad with the thick 

 outer cortical tissue of the peduncle. 

 In the cone axis the thick sclerotic cor- 

 tex is largely absent. The peduncle is 

 nearly bare adjacent to the cone, but 

 proximally it bears a number of short 

 bracts in an irregular spiral arrange- 

 ment as shown by the segment illus- 

 trated in text figure 4. The bracts, as 

 shown by transverse sections of the two 

 ends of this segment, obviously vary in 

 their arrangement. The drawing (text 

 fig. 4) was prepared from a peel which 

 covered both of the transverse surfaces 

 and one tangential surface so that the 

 structure in both directions is contin- 

 uously related, but the proximal end is 

 sectioned at a deeper tangential level 



than the distal end. The dimensions of 

 the peduncle increase slightly away 

 from the proximal end.^ A greater 

 number of bract bases are transected 

 at the distal end and the stele is some- 

 what larger there with more protoxylem 

 points. Orientation is proved by the 

 manner of attachment of the bracts. 

 Steles from both ends are diagrammatic- 

 ally represented) at higher magnification 

 at the left of the text figure. The pith 

 area is invaded somewhat by medullary 

 tracheids as in the cone axis. 



A more complete account of the varia- 

 tions in the peduncle cannot be pre- 

 sented at this time. Additional study is 

 needed since the structure of the ped- 

 uncle is particularly important in estab- 

 lishing the relationship of Mazocarpon 

 with better known genera identified on 

 the basis of stem structure. It is a 

 matter of interest that a ligule appears 

 to be present in the axil of one bract 

 shown in nearly median section in text 

 figure 4. 



^The form that Lesquereux first named Lepidos- 

 trohus lacoei (1880, p. 439), later referred to 

 Lycopodites (1884, p. 780), which is illustrated in 

 vol. Ill of the Coal Flora (pi. CVII, fig. 1) is of 

 interest. It appears to have no connection with 

 either Lepidostrohus or Lycopodites and instead is 

 properly referable to Sigillariostrohus. This genus, 

 as mentioned later, compares favorably in several 

 respects and is intimately related to Mazocarpon. 

 Lesquereux's specimen apparently shows the com- 

 plete peduncle which in this case is devoid of 

 bracts except for a few near the base of the cone. 

 The peduncle varies in diameter from about 7% 

 mm. at the proximal end (where it presumably 

 was attached to the trunk of the tree) to about 

 4 mm. near the middle from whence it again ex- 

 pands to about 8 mm. in diameter at the cone 

 base. In all it is about 14 cm. in length. The 

 peduncles of Sigillariostrohus goldenhergi (cf. 

 Zeiller, 1884, pi. 12, fig. 5) and of other species of 

 Sigillariostrohus, while often less complete, also 

 show some indication of a similarly inconstant 

 diameter. The seemingly anomalous feature shown 

 by a sector of peduncle of Mazocarpon oedipternum 

 in text figure 4, with a distal diameter greater 

 than the proximal may thus be in general agree- 

 ment with peduncles of other cones of sigillarian 

 affinity. 



