28 



Photnjiiicrngniplis of Bntfiiiical Siiuiic:^. 



36. — T.S. Germinating radicales of a grain of Barley. 



Pericarp of 

 seed. 



Absorptive la-^^-er 

 i^ Nucleated tissue 



-/■ oP sutelUm 



De\'elopin_L; 



primary roots. 



Developing 

 secondary roots 



37. — Entire plant of " Lemna minor." (Common Duckweed). 



Fronds containing bundles of raphides. 



Developing fronds. 



koot. 



Root-cap. 



