J 9^o] HOLM—CICER ARIETINUM 



449 



outside the protohadrome vessels, giving rise to several strata of 

 thin-walled parenchyma. This parenchyma formed outside the 

 four strands of hadrome becomes the first medullary rays (fig. n, 

 M). This more advanced stage is readily seen in fig. 9, where the 

 cambial strata (Camb) are very conspicuous, beside the com- 

 mencement of the formation of the four medullary rays outside 

 the vessels. The pith remains unchanged, without becoming 

 sclerotic, and contains no deposits of starch. A corresponding 

 structure occurs in the lateral roots, borne on the primary, but 

 the cambium is not so abundant. If we examine the urimarv root 



fruiting specimen 



in fig. 11. All 

 dermis inclusive 



from epidermis 



walled, homogeneous cork (Co), and a secondary cortex (C) in 

 which the four stereomatic strands are yet distinct. The cork 

 and the secondary cortex are the products of the cell division 

 within the pericambium. Furthermore, the deep medullary 

 rays may be seen, only two of which have been drawn, and these 

 (M) proceed from the old hadrome rays (PH), where they were 

 formed originally. Secondary medullary rays are also developed. 

 They commence within the secondary hadrome, and are shorter 



much 



The stele is now much 



broader, and contains secondary stereome (fig. 12, St) as cells 

 scattered outside the leptome, also among the secondary vessels 

 (fig. 14, St). On the other hand, the central portion of the stele, 

 with the four rays of hadrome and the pith, are unchanged, while 

 the primary leptome has become absorbed completely. These 

 secondary formations within the stele, that is, the medullary rays, 

 the stereome, the secondary leptome (L), and hadrome (H), are 

 all products of the cambium (fig. 9) . 



Characteristics of the roots of Cicer, therefore, are the abundance 

 of stereids; also, that the increase in thickness commences within 

 the stele proper and not in the pericambium. The fact that a 

 cambium becomes developed as a circular band between the 

 secondary leptome and hadrome (fig. 11, Camb) shows that further 

 increase in thickness is secured in exactly the same manner as in 

 the collateral mestome strands of a dicotyledonous stem. 



