SPH^ROSTOMA OVALE FROM PETTYCUR, FIFESHIRE. 



Within the sinus (si.), surrounded by the free part of the inner integument or 

 " canopy " (ca.), may be seen the nucellar cap (n.c.) or free part of the nucellus. This 



PlaMloflL.C 



Text-fig. 1. — Diagrammatic drawing of a median longitudinal section of Spheerostoma ovale, still surrounded 

 by the cupule. The description is given in the text. 



a. =archegonium. 

 ab. = abscission layer. 



c. = cupule. 

 ca. = canopy. 

 e. s. = embryo sac. 



/.= frill. 



n.— central column surrounded by 

 the pollen chamber. 

 n. e. = nucellar cap. 



p. = plinth. 

 p.c. = pollen chamber, 

 s. —sclerotic hypoderm. 



v). = wall of the pollen chamber. 



si. = sinus. 

 v.6. 1 = a vascular strand of the cupule. 

 v.b. 2 = & vascular strand of the inner 



integument. 

 v. 6. 3 = central supply strand to the 

 ovule. 



consists of the plinth (p.) which is relatively flat, and the central nearly hemispherical 

 dome or "lagenostome " which rises abruptly from the centre of the plinth. 



