590 



BOTANY 



PART II 



portion of each carpel, leaving the seeds attached by their stalks to 

 the central portion formed by the placentas together Avith the false 

 septum. Rarely the fruit is indehiscent. Embryo curved. Endo- 



FiG. 582. — Cruciferous fruits. A, Cheiranthus cheiri ; B, Lepidiwiu sativum; C, Capsdlv. Inrsa 

 pastons; D, Lunaria biennis, showing the septuui after the carpels have fallen away. E, 

 Crambe maritima. (After Baillon.) 



sperm wanting or reduced to a single layer of cells coherent with the 

 seed coat (Figs. 580-586). 



Distribution, in tlie northern hemisphere, especially in the Mediterranean 

 region. 



The form of the fruit and the position of the embryo in the seed are used in 



jnvB 



Fig. 583. — Transverse section of the seed of 

 Brassica nigra, rail, radicle ; cut, cotyledons ; 

 2Jroc, vascular bundles. (After Moller.) 



A 



Fig. 584. — Seeds of Ciuciferae cut across to 

 show the radicle and cotyledons. A, 

 Cheiranthus cheiri {x 8) ; B, Sisymbrium 

 alUaria (x 7). (After Bailt.on.) 



the subdivision of this extremely uniform family. This general classification, which 

 dates from the time of Linnaeus, will be used here, but reference must be made to 

 the more recent, natural division of the family, founded on characters atforded by 

 a number of organs, which is given in the Natilrliclien Pflanzenfamilien by Peanti,. 



