MORPHOLOGY, GENETICS AND BREEDING 49 



that the flowers develop in the axils of the leaves. Richter (59) described 

 the inflorescence w^ith its bracts as an axillary head or compressed spike 

 with a 2/5 phyllotaxy in the arrangement of its flowers. 



In systematic treatments of Arachis, the inflorescence is described as 

 spicate or subpaniculate. The inflorescences are not terminal but always 

 occur in the axils of foliage leaves or cataphylls. They never occur at the 

 same nodes with vegetative branches and form with the latter a definite 

 branching pattern. Each inflorescence bears three to several flowers. The 

 flowers usually appear one at a time but two may open simultaneously 

 in the Spanish type. Flowers on the same inflorescence may appear daily 

 or at intervals of several days. 



An inflorescence (figure 13) irrespective of whether it arises in the 

 axil of a foliage leaf or in the axil of a cataphyll, produces a cataphyll 

 at its first node. Each successive node of the inflorescence also has its 

 cataphyll in the axil of which arises the simple flowering branch. The 

 flowering branch is exceedingly short and possesses a single cataphyll, 

 bifid or simple, in the axil of which the flower bud appears to develop. 

 The production of the flower terminates further branching. The in- 

 florescence can be seen then as a reduced and compressed replica of the 

 vegetative shoot reduplicating its phyllotaxy and axillary buds, differ- 

 ing largely from the latter in the reduction of organs and the suppression 

 of further growth through the production of flowers. The internodes of 

 the central axis of the inflorescence may later elongate, producing a 

 much expanded fruiting structure. The growing point of the central axis 

 occasionally becomes vegetative and pursues a limited amount of 

 growth. New inflorescences may then be laid down in the axils of the 

 foliage leaves occurring at the end of the original inflorescence. Thus it 

 can be seen that what is customarily a reduced and simplified branching 

 system sometimes may become so involved that at maturity the untrained 

 observer cannot distinguish vegetative from reproductive branches. 



Flower 



The flowers (figure 14) of Arachis are yellow, papilionate, and sessile. 

 The development of a remarloible perigyny in volving an unusually long,^ 

 hypa nthium or " calyx tube" has led to the erroneous supposition that the 

 flowers are long pedicellate. The base of the hypanthium is actually in- 

 serted practically at the end of the simple flowering branch and is sub- 

 tended directly by its cataphyllar bract. The hypanthium is pubescent. 

 The external portion of the tube expands above into five calyx teeth, 

 four of which are fused into a superior lip which stands back of the 



