MORPHOLOGY, GENETICS AND BREEDING 63 



and higher order branches. This fact, in addition to the extreme reduction 

 of the first internode of most of the lateral branches, so that in second- 

 order branches the first cataphyll may be closely appressed to the main 

 stem, leads to the erroneous impression that twin buds occur in the leaf 

 axils on the main stem axis. 



A botanical key to the varietal groups of peanuts follows : 



A. Lateral buds of the central axis all vegetative. First cataphyllar node of 

 n + 1 order branches vegetative ; second occasionally reproductive.* 



(a) n -|- 2 order branches occur as pairs of vegetative branches alternating 



with pairs of reproductive branches Virginia 



AA. Lateral buds of the central axis vegetative or reproductive. First and second 

 cataphyllar nodes of n + 1 order branches reproductive. 



(a) n -)- 2 order branches irregularly reproductive and vegetative. Pods 



two to three seeded Spanish 



(aa) n + 2 order branches all reproductive or sometimes mostly vegeta- 

 tive distal to the 6th-8th node, n -f- 3 order branches all reproductive. 

 Pods 3-6 seeded Valencia 



* See previous sections. Vegetative Structure of the Mature Plant: Stem; and Reproductive 

 Morphology: inflorescence. " 



Figure 18. — An n-\- 1 order, cotyledonary lateral branch of a Virginia runner pea- 

 nut. Two n -\- 2 vegetative branches arise from the first two nodes of this 

 Isranch, two n + 2 reproductive branches from the next two nodes, two n + 2 

 vegetative branches from the next, two n + 2 reproductive from the next . . . 

 The same pattern of alternating pairs of nodes appears on each successive order 

 (n -\- 2, n-\- 3. n-\- 4) of vegetative branches, so that the occurrence of repro- 

 ductive branches does not limit the extent of the branching system. The branch- 

 ing order may but usually does not exceed n-\- 4 vegetative and n -\- 5 repro- 

 ductive in Virginia runners. 



