•"58 



his early reading of the authorities could he recall so much as a 

 suggestion that such things ever occur.* Here then was a chal- 

 lenge which could not be ignored or neglected. 



2. After careful examination of many specimens it became 

 clear that each tree of this species has passed through several 

 distinct phases of phyllotaxy, namely: (i) The initial pattern of 

 infancy, not included in the record, and at this stage not yet iden- 

 tified, but later found to be of the 5-ranked pattern (cf. Chart, 

 Zone I). (2) At an uncertain distance above this the record 

 begins in the midst of a zone of no recognizable pattern whatever, 

 because it ofifers no vertical alignments to form the basis of a 

 numbered scheme (cf. Chart, Zone II). (3) Near the upper 

 edge of this zone, out of what is apparently mere confusion, there 

 presently emerges a recognizable group of oblique spiral ranks 

 which, curving sharply upward, presently reach verticality. There 

 are thirteen of these ranks — so now we know where we stand, 

 though not as yet just how w^e got there (cf. Chart, Zone III). 

 (4) This vertical alignment sometimes continues unchanged 

 through a space of several feet. Quite as frequently, however, 

 the thirteen ranks merely touch verticality and then gradually 

 swerve away from it. But in either case they do not lose them- 

 selves in confusion like that from which they emerged at first.* 

 For here the 13-ranked pattern in its entirety is visibly carried 

 forward along these curves without dislocation or change, save 

 that the whole is slightly tilted in conformity with their deflec- 

 tion (cf. Chart, Zone IV). (5) This gradual rotation of the pat- 



* In the writer's student days the botanical authorities within his reach had 

 very little to say concerning deviations from the regular series of leaf-patterns 

 except as the deviations were the result of seasonal changes in the growth of 

 the plant, or of modification of leaves to subserve new functions. Since then 

 it has not been possible for him to follow up the later developments of phyllo- 

 tactic theory. While acknowledging the seriousness of this handicap for the 

 present task, he still ventures to think that in one way this r.ay not have been 

 wholly a disadvantage — it has a; least left him free from theoretical bias to 

 deal with the facts as he found them. 



* This double curve of the 13's, with its two arms meeting in Zone III, is 

 the most noticeable feature of the whole record and a valuable landmark for 

 the investigator. Its curvature is always convex toward the direction of the 

 primary spiral. Cf. Section III, 3 infra. 



