Relation of Ptendosperm Anatomy to that of Cycads. 61 
structure (Fig. 15, b). In another plant, at a slightly lower level 
(Fig. 15, n), the first extrafascicular ring consisted of an interrupted 
collateral zone ; second and third rings also occurred with traces of 
inverse bundles indicating, according to Worsdell, the solenostelic 
origin of the rings. Medullosa stellata v. gignntea and Medullosa 
Solmsii v. lignosa are of interest in comparison with these cases, for 
they had already “ advanced very far in the modern Cycadean 
v- 
Vnver>ttdl ethanol 
Pino 4 ., 
cerXr*a\ 
eylmdet 
Fig. 15. Cycas Seemanni. A, 
Transverse section of a portion 
of three extra vascular rings in 
the primary nodal region of the 
root. 
B, Transverse section of a 
portion of three vascular rings 
in the primary nodal region of 
the stem. (After Worsdell, 1901). 
