﻿i 9 i6] M ICHELL — RICH A RDIA AFRICANA 335 



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1905. 



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EXPLANATION OF PLATES XXI-XXIII 



Fig. i.— Young ovule showing megaspore mother cell with nucleus just 

 coming out of synapsis; X 12 10. 



Fig. 2.— Formation of equatorial plate in heterotypic division; X1210. 

 Fig. 3.— Homotypic division; X1210. 

 Fig. 4.— Row of 4 megaspores; X520. 



Fig. 5. First division of embryo sac nucleus; two degenerating mega- 

 spores seen above it ; X 5 20. 



Fig. 6.— Two successive sections (a, b) showing the 2-nucleate embryo 



in the 4-nucleate embryo sac; X 520. 



X520. 



Fig. 10.— Successive sections (a, b, c, d) showing 8-nucleate embryo sac 

 after upper polar nucleus has moved down; X520. 



Fig. 11.— Successive sections {a, b, c) showing mature embryo sac with 

 egg (e) and 2 synergids (jv»), the two polar nuclei (p), and 3 degenerating 

 antipodals (ant); X520. 



Fig. 12.— Fusion of polar nuclei; X520. 



