unless there may be some reason to the contrary. Invars.:-, implies an intentional 

 growth-curvature, apart from the pendulous effect of weight : and its result is 

 undoubtedly that of further protection of the cone-structures from Sea : . _::on of direct 

 insolation. The more advanced ty : -- invert immec. "ter pollination (Pinus : 



Pic -:a, Pseudotsuga), yet others (Cedrus. Larix. A::-:. 2%tya retain and -. -~. 

 emphasize the primary vertica. - ::on. The mechanism of such inversion implies 

 the possibility of a growth -intercalation in the cone-stalk : and where sufficient exta 

 is lacking, the growing cone may be involved in the curvature, leading to effects of 

 asymmetry in the adu! :ure, with increased growth of the members on the outer 



convex side, often extremely conspicuous : P. j'n^r.::. P. C and to a lea 



in P. sykesiris). 



(7) Cork is commonly formed or. die exposed surface of the umbo only (Pinus) ; 

 while resin-exudation appears between the in; i -;ales of the ~-r.-vear cone 

 (Pinus sykestris], effectively sealing all chin/.?: in others (P. txceka) re-.r. -:reams 

 over the entire surface of green cones, and mi; - ; h/.e stalactites from the ends; 

 excessive exudation, as icing on the erect cone c:~ A rnifica, 



X. Mechanism of Seed-discharge and Dispersal : 



The greater the perfection of the me::.:.r.:-rr. for sealing the cone ^ a ::er:r.r_ytic 

 construction protecting the developing -TT:?. the more important alsc becomes die 

 necessity of prodding a converse mechar. -~ ::r openir.u it agai ai : [berating die 

 seeds. These again require to be abstricted. or some alternative met'r. : i ; :" detachment 

 must be provided. As a matter of fact it is obvious ir.it the opening of the Pine-cone 

 and the dispersal of its winged seeds by the agency of the wind constitute sndi 

 an elaborate provision, the factors of which require to be analysed: while ahem 

 methods and constructions may be coninstei in the scale :f efficiency, is in Ifae 

 common example of the chances of bird-dispersil in T~x-^s and /#/:;/: -;,.-. 



With the original failure of the megaspore to be discharged from the rne.:i- 

 sporangium which iniiiites :he ' seed-habit '. the r.. --.. :':: Sspersa] onpfies that 

 separation or abscission must be passed on tD some other stmctmc enc King die 

 megaspore and its contents : as (i) the megasp:"ir._- _m (crulf}. (: die leaf be:.' :.. 

 it (carpet), (3) the axis bearing the carpel (Jloicer), (4) sorte :.:.-: move istanl 

 connexion (as the entire inflonsctnci}. In order of priority aid ; .. letic proba: 

 the abscission of the ovule with its dormant embryo, as the sad. rep:e-er.:5 die first and 

 simplest solution of the problem. It may be hence assumed ffaaf the seeds of 

 Conifers were primarily ats:~:;:ei an I se: crated from the parent-plant :: germinate 

 elsewhere ; whether by the simple separation of I es dire . .; as in Taxoids and 



Guttgo(fx Cyc:. - ' .:h foliaceous carpels), or again in the ;ise cf ir.t dosed Pii 

 cones. In the latter it is evident that i seiondary opening mechanism must be also 

 proud ed, before the seeds can escape, as ag:.:r. that such dehiscence must be 

 primitive; and any minor examples cf indehiscence are to be regarded is ifae 

 expression of failure in the original mechanism. In both cases the otfluation of some 

 external locomotor agency will be advantage: us from ir.e standpoint of convey ir.:e :: 

 a distance; whether in the elementary form :f Effective :. .r-currents. or in more 

 elaborate association with the wings of birds. 



The simplest case of ovule absciss: :n .s confined to Taxoids, since closed cone- 

 structures have been so far lost, and the ' naked ' : wnfes -'.:: a. The secondary 

 and necessarily comparative'.;.- late erolntian ::" bird-association can only nrOhx 

 structures already in existence from the standpoint of xerophyti: protection by r. 

 of succulent (aqueous) tissue, or sderosed stone-cells- the :..cal adaptations 

 running closely parallel with 'berry' and l drupe '-:": million amcr.r Aru.j^.rrms 

 In GimkgoytnA Cepkaletaxms the d.ri'rrrr.i.ition of a sderotesta and sarcotesta tnay 

 show additional effects in coloration (by residual carotin or anthoc; . ; ^mentation), 

 more or less storage of sugar on ripening', is a sute of incipient decay, and die 

 parallel differentiation of succulent aril ar.d sderosed testa follows closely sin 

 mechanism in Taxus. Torre) \ and sp-. . es :f Podocarpta. Ir. ieranlt ;f bird- 

 risitation, alx - n of the ovnle follows normally in Donrse of time j-iiesof 

 specialization in such mechanism may be observed (cf. the dun leather] green aril of 

 Torrtya . .: .'."" rmca with the case of TJ.YUS ' rn with avkfity as sc :r. is rip-e 

 in November). 



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