RAPHANUS SATIVUS zS^ 



of the two functional stamens are the nectaries. (Fig. 142., F.) 

 There are four equal stamens in the inner whorl which lie opposite 

 the petals. The anthers of the functional stamens are two-loculed 

 at maturity and longitudinally dehiscent. 



The pistil has been interpreted as consisting of four carpels by 

 Eames and Wilson Ql, 3). Based upon the character of the vascular 

 supply of the ovary, they state that 



"it appears that there are four carpels in the Cruciferae instead of two, 

 the generally accepted number. Two of these carpels are valve-like 

 and sterile and are placed below two other carpels, nearly enclosing 

 them. This second set of carpels, the fertile or 'solid' carpels, is 

 reduced; the loculus has disappeared, and the ovules borne by these 

 carpels have been forced out of the loculus and lie in the loculus of 

 the valve, or sterile, carpels. This has taken place phylogenetically, 

 not ontogenetically." 



Saunders (15, 16) also describes the gynoecium of the crucifers as 

 consisting of four carpels and presents the concept of carpel poly- 

 morphism to explain the occurrence of different combinations of 

 various carpel types, stating that "when the median carpels become 

 solid the characteristic form is a siliqua, when they become semi- 

 solid the result is a silicula." 



A somewhat different interpretation of the relationship of the 

 floral parts is presented by Eichler (4), and this has been accepted 

 at least in part by Sachs (14) and Strasburger (18). In the Eichler 

 system, the typical cruciferous flower is described as consisting of 

 two lower median sepals, two upper lateral sepals, four diagonal 

 petals in one whorl, two lower lateral stamens, two upper median 

 stamens, and two lateral carpels. The cycle of apparently four 

 inner stamens is regarded as consisting in reality of but two sta- 

 mens, each of which is branched at its base. This concept of the 

 dimerous symmetry of the flowers of the Cruciferae was carried a 

 step further by some of the early botanists who regarded the four 

 petals as being derived from a single pair by a lateral doubling or 

 branching, in a manner similar to that described for the inner whorl 

 of stamens. 



ANATOMY 



Ontogeny of the Flower. — In the ontogeny of the flower, the 

 origin of the floral parts does not occur in acropetal succession; 

 and like Capsella, as described by Coulter and Chamberlain (i), the 

 petals are the last floral organs to be differentiated. The primor- 



