114 OEGANOGEAPHT AND GLOSSOLOGY. 



of the plant, lengthens during germination, the cotyledons are raised, and appear 

 above ground ; they are then said to be epigeal (c. epigwi, Kidney -hean, fig. 650 ; 

 Radish, Lime). When the caulicle is very short, and the plumule (which forms the 

 second internode) rapidly lengthens, the cotyledons remain in the ground, often even 

 within the seed-coats ; they are then said to be hypogeal (c. hypogwi, Spanish Kidney- 

 hean, OaTc, Graminew, Orange, fig. 651). 



In monocotyledons, the evolution of the radicle presents a remarkable pecu- 

 liarity: it is provided at the base (fig. -642) with a sort of sheath, named the 

 coleorhiza ; this is nothing but an outer cellular layer which, having been unable to 

 accompany the development of the radicle (e), has been pierced by it. 



