dates back to the sea, and normally appears in land-plants as an alternative for 

 dichotomy of the shoot-apex (cf. Lycopodium) ; it is a fact of observation rather than 

 a law ; and hence may be assumed to represent the most generally successful method 

 of shoot-ramification yet attained. 



The phyllotaxis-construction of every axillary bud is initiated independently at 

 its own apex ; each new lateral in fact starting off in the manner of a new seedling- 

 apex. Though certain relations of symmetry may normally obtain in some cases 

 between the primary system and the secondary axes (cf. Phyllomorphs), there is no 

 reason to suppose that the position of adjacent members, or any assumed pressure of 

 the subtending leaf on the emergent bud has anything to do with the arrangement 

 adopted. 



The highest Conifers utilize the greatest number of axillary buds, and express 

 greater complexity in such selection and differentiation. The ingenuity of the 

 mechanism is probably centred in the fact that the axillary bud is normally in 

 a position to be supplied with food from the subtending leaf; hence with the 

 differentiation of the leaf-member for special functions other than that of photo- 

 synthesis, axillary ramification is at once suppressed (for want of local food-supplies). 

 Thus bud-scales and reproductive leaves (stamens) omit axillary growths ; the case 

 of the Pine-cone may be left open for the present. 



Ramification from the leaf-axils of a reduced spur-shoot is also rare (Ginkgo, 

 Cedrus), but occurs normally in Taxodium : more than one bud from an axil does 

 not occur in Conifers ; hence such trees stripped of foliage-spurs have no power of 

 recovery. On the other hand, Taxus, with few axillary buds, may produce shoots 

 from dormant axils in profusion on clipping. Total suppression of all lateral buds 

 whatsoever may be looked for, but would be regarded as a freak; occasional in 

 Spruce, giving a single unbranched stem very conspicuous among associated seedlings 

 as the ' disbudded mutant ' (cf. Helianthus, giant-strain ; Zea). 



The greatest differentiation of axillary buds obtains in Pinus, in which such 

 lateral derivatives are strictly localized, of the form (i) lateral leaders, (2) foliage- 

 spurs, (3) staminate flowers, (4) ovulate flowers, as expressing local segregation of 

 special morphological factors in the apices concerned. This segregation is so definite 

 that any departure from the rule would be regarded as an anomaly ; e. g. where 

 lateral leaders or ovulate flowers replace foliage-spurs in the middle of the annual 

 shoot (case of ' multinodal ' Pine), or a foliage-spur producing juvenile leaves (Pinus 

 rtgida). On the other hand, in Taxus, vegetative buds, or ovulate shoots, arise without 

 rule, and any foliage-leaf may subtend any type of lateral, or produce none at all ; 

 this extending even to the occasional production of ovulate flower-shoots on the 

 staminate tree. 



Types widely dissociated, as Cedrus and Ginkgo, normally utilize the axils of all 

 the primary leaves of the main axis (except bud-scales) for the production of specialized 

 photosynthetic spurs, with a few leaders. In others, leaders (' long shoots ') are pro- 

 duced apparently casually from the axils of leaves at considerable distances (Larix\ 

 or from rhythmically selected members of the phyllotaxis-system (Araticaria excelsa). 

 Staminate and ovulate flowers are similarly produced (Picea, Abies], the tendency 

 being to produce them more freely at the distal end of the annual shoot, as the 

 expression of an 'upward drift' of food-supplies to the vicinity of the growing-point 

 and the elaborating winter-bud. Such flower-shoots may be numerous (Picea, Abies) 

 or few (Araucaria).' 1 The ultimate restriction of the lateral leaders to a cycle at the 

 distal end of the shoot gives the case of the ' false-whorl ', typical for the more precise 

 Ptmes-type and for Araucaria; less accurate in Picea, Abies, and multinodal Pines. 



1 Comparison of young plants of Picea excelsa or Abies pectinata shows clearly that such 

 restriction of laterals to the immediate vicinity of the terminal bud is an effect of enfeebled nutrition. 

 In such ramuli with D.V. laterals two buds (right and left of the terminal") give the limiting case 

 before complete suppression of the laterals altogether as in lower branches. Such enfeebled nutrition 

 again is not the effect of failure in carbohydrate photosynthesis, or of effective insolation, so much as 

 the consequence of lack of food-salts for further proteid-synthesis, and thus appears as the result of 

 failure in the transpiration current and water-supply. A bias for the inception of such morphological 

 phenomena as the 'false whorls' of Pinus, and the bilateral frond-systems of Araucaria, is inherent 

 as the response to the effect of xerophytic conditions, however much such morphological factors may 

 be subsequently specialized as constants in the generic equipment. 



