PISUM SATIVUM 



361 



Floral Development. — Floral development in the Legumino- 

 sae has been investigated for several genera, including the work of 

 Goebel (10) on Phaseolus and other legumes; Gregoire (ix) on 

 Lathyrus; Bugnon (3) on Lathyrus, Trifolium and Lupinus; West- 

 gate, Coe, and others (31) on Trifolium; Coe and Martin (4) on 

 Melilotus; and Guard (13) on Soja. The floral development in 

 these genera is in agreement with that of Pisum, the only important 

 difference of opinion being in regard to the character of the car- 



ad bii 



Fig. 183. A-E, diagrammatic longisections of flower bud showing stages in development ; 

 F-I, diagrammatic transections of carpel in E, showing vascular anatomy and origin of ovules : 

 ab bu, abaxial bundle; ad hu, adaxial bundle; ad su; adaxial suture; bet, bract; car, carpel ; 

 Of, ovule; ovy, ovzry; /k?^, pedicel ; p^r, petal ; j?, sepal ; j/^, stamen. 



pellary development in which the interpretation of Gregoire is 

 not in complete accord with the findings of other investigators. 

 The flower primordium first appears as a knob-like growing 

 point of meristematic tissue in the axil of a bract. (Fig. 183, /4.) 

 The sepals, petals, outer cycle of stamens, inner cycle of stamens, 

 and carpel then appear in the order named, but the subsequent 

 development and maturation of the floral parts does not follow this 

 succession. The first of the five sepal primordia arises from the 

 growing point on the abaxial side, followed by the development 

 of the two lateral lobes of the calyx, and, finally, the two adaxial 

 lobes. (Fig. 183, B.) Shortly after the initiation of the pri- 



