z^ 



MORPHOLOGY OF GYMNOSPERMS 



the other a form reduced wholly or partly to naked branches, whose 

 ultimate branchlets bore terminal seeds of the Lagenostoma type. 

 There was no more organization of a strobilus than in existing ferns 

 with dimorphic leaves. Additional species have been described 

 also by Grand Eury (53), who found in the Lower Coal-measures 

 a very large number of small LagenostomaAike seeds associated with 

 species of Sphenopteris under conditions that seem to make it certain 

 that they belonged together. 



Fig. 27.- — Lagenostoma Lomaxii: longitudinal section through apex of seed; o, 

 opening at top of pollen chamber; i, integument; n, central core of nucellus; «', 

 outer hard layer of nucellus; p, pollen chamber; g, pollen grains; n" , part of nucellus 

 supporting the pollen chamber; m, megaspore membrane; Xabout 50. — After Oli\'ER 

 and Scott (48). 



The structure of Lagenostoma Lomaxii has been described in full 

 by Oliver and Scott (39, 48). The seeds occur in the Lower 

 Coal-measures, and each one is invested by a lobed cupule "springing 

 from the pedicel just below the base of the seed and extending above 

 the micropyle, at least in young specimens. The cupule appears 

 to have been ribbed below and deeply lobed above, and in form it 

 may be roughly compared to the husk of a hazelnut, of course on a 

 very small scale" (fig. 25). The integument, which is free only in 

 the region of the pollen chamber, is a remarkably complex structure. 

 A transverse section shows an outer hea\y zone, and an inner one 

 consisting of several chambers (usually nine) filled with parenchyma, 



