also evident that the continued precocity in the production of protective (xerophytic) 

 mechanism affords the clue to the evolution of the cone, as again only a phase of 

 the same progression in land-flora, and probably contemporaneous, which initiated the 

 Angiosperm ovary, closed before pollination even, and ultimately elaborated as a 

 sealed chamber before the appearance of any ovules (Orchidaceae). 



VII. Specialization of the Cone : Regarded as the product of an abbreviated 

 phyllotaxis-system of bract-scales, subtending axillary megasporangia (i or more), the 

 progression of cone-factors subsequent to pollination follows a general course which 

 is primarily the expression of xeromorphic adaptations in connexion with (i) the 

 protection of the enclosed gametophytes from exposure and desiccation; (2) these 

 protective adaptations are further elaborated after fertilization into the stage of 

 the maturing seeds; and (3) they finally attain further complexity in the provision of 

 mechanism for the separation and discharge of the seeds, as also (4) aiding their 

 possible dispersal. 



Such changes involve : 



(a) Basal intercalation of new extensions in the scales following the enlargement 



of the ovules. 



(/?) Inversion of the ovules, commonly following basal intercalation, as the 

 micropylar end, with the sexual phases or embryos to be protected, is 

 maintained as far from the surface as possible, 

 (y) The sealing of the cone by extensions from the bract-scale, or by the new 



growth ultimately distinguished as the ' cone-scale ' . 



With these may be included a feature of the non-coning Taxoids as the initiation 

 of a new basal growth to the ovule as a ' second integument ', ultimately distinguished 

 as the 'aril' (Taxtis). The last point expresses the special feature of protective 

 investment in the Taxoid series (including Podocarps) ; the third (y) expresses 

 the evolution of the characteristic cone-scale of the Finoid. These secondary 

 mechanisms have much in common ; but there is no need to press homologies 

 too far, or to obscure the relations under such expressions as ' unilateral aril ', or 

 ' epimatium ', in order to bring everything under one morphological generalization. 

 The need is the same in all ; but the method of solving the problem is not necessarily 

 identical in different phyla. 



Given the theoretical axillary position of the megasporangium, and its direct 

 axillary bundle-supply, the basal (' chalazal ') end of the ovule affords a guide to the 

 original axillary region, and to the amount of intercalated growth. The addition of 

 new bundles at this point will be wholly secondary, as correlated with the increasing 

 size of parts and the problems of the food- and water-supply of new regions. 

 Such bundles may be expected to be symmetrically spaced, but once removed from 

 the vestigial dorsiventral leaf-construction, their orientation excites no special interest. 

 It is interesting to note that identically similar problems occur in the case 

 of Angiosperms ; the ovary-cavity being normally extended by basal intercalary growth 

 (cases of syncarpy and epigyny), as the ovules are also commonly inverted (anatropous), 

 and may possess two integuments which are difficult to justify except as vestigia of 

 some older function. New vascular bundles are again added in nucellus and testa- 

 layers as the seeds enlarge (cf. Heh'anthus with 2 lateral V.B. from the chalaza, much as 

 in Podo carpus ; fuglans, Cocos). It is in fact difficult to avoid the conclusion that 

 such phenomena as the inversion of the ovules, double integuments, and accessory 

 bundle-supply of seeds, were established in Angiosperm ovules before the evolution of 

 their characteristic ovary-chamber ; that is to say, while these phyla, now classed as 

 Angiosperms, were still in an antecedent Gymnospermic phase of reproductive 

 mechanism, of which at this time only vague suggestions persist. 



Note, (i) Basal intercalations to keep pace with the enlarging ovule before 

 fertilization are analogous to the general increase of the Angiosperm ovary to keep 

 pace with enlarging seeds after fertilization, as the necessity for the protection of the 

 parasitic prothallia is continued and even increased. Growth takes place in three 

 dimensions, and the cone normally increases in volume while maintaining its relative 

 proportions ; though the case of the Finns apophysis (cf. P. Pinea) shows that such 



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