In the Pinoid series arrangements for opening the sealed cone are provided for 

 in the simplest manner by the mere shrinkage of the tissues on death and desiccation, 

 and the abstricted ovules merely fall out to be drifted by the action of the wind. Such 

 an elementary state of affairs persists in Cupressineae (Thuya, Libocedrus); additional 

 gape of the scales being provided for by greater sclerosis on the inner side, or less 

 peripherally ; such cones once completely dried do not again recover closed volume 

 on being wetted (Cupressus, Thuya). With greater succulence and less sclerosis (Biota) 

 shrivelling of the cone is more pronounced, and this is still more complete in 

 funiperus sphaerica with practically no sclerosed tissue at all. Cones of the Taxodineae 

 remain at the same level of attainment ; the scales shrink, often considerably 

 (Crypfomeria)) but do not recover full volume, or completely close on wetting : the 

 seeds retain a narrow point of attachment and fall out of the cone as it dries 

 (Sequoia). 



In all these cases with closely adpressed scales in condensed cone-formation, the 

 seeds grow to fill narrow chinks in the interior, sending out laminate regions of the 

 testa, as more or less ' wing '-like lateral extensions on both edges of the compressed 

 seed (Cupressus, Thuya, Sequoia). In the more succulent forms (Biota, Juniperus) 

 such extensions are conspicuously wanting, but all such wing-formation parallels the 

 general case of simple winged seeds and enclosed fruits of Angiosperms (cf. Betula\ 

 Further elaboration is noted in the case of the Araucarineae ; the single median seed 

 of Agathis similarly sends out bilateral extensions of the testa, but only one side 

 normally develops considerably, attaining an effective unilateral ' spinning ' wing. In 

 addition to this the scales are separated from the cone-axis. The latter phenomenon 

 may be included as secondary shedding of the megasporophyll ; in Araucaria this 

 replaces the abscission of the ovules ; the latter being so fused up with the scale that 

 it comes away in one piece with included seed. In A. imbricata and A. Bidwilli the 

 great size of the seed prevents much distant dispersal by gentle wind-currents, nor do 

 such scales show any adaptation for spinning movements. The spinning of Agathis 

 is so far an independent evolution of the mechanism from bilateral testa-extensions; 

 and though giving a possible limiting velocity of 2-| ft. per sec. is by no means 

 so neatly adjusted as in the case of the Abietineae ; early stages of similar unilaterality 

 may be noticed in the seeds of Libocedrus decurrens. Similar shedding of the scales 

 from the cone-axis obtains in some Abietineae, where the bract-scale and cone-scale 

 fall away in one piece (Abies, Cedrus, Pseudolarix], and though wholly wanting 

 in Picea, Tsuga, and Pseudotsuga, may be sporadic in a few forms of Pinus (P. Pinea, 

 P. palustris), possibly as a retention of older mechanism. 



In all these Abietineae, also, more perfect cone-opening becomes the rule ; this 

 mechanism being also transferred to the ' cone-scale ' growth, repeating the same 

 sequence of shrinkage and divergence of the scales, in accordance with the distribution 

 of sclerosed tissue, and with the same result that cones with less sclerosis shrink 

 more, and do not completely recover volume or completely close on wetting (Pinus 

 excelsa, P. Strobus}. Opening and closing movements in response to hygrometric 

 changes are more pronounced in Picea, Tsuga, Larix, Pseudotsuga ; but the more 

 massive sclerosed cones of the Pine series show the greatest advance ; divergence of 

 the scales being often associated with strong deflecting curvatures in the hooked 

 apophyses (P. Coulteri, P. Sabiniana, P. Gerardiana). 



With the great development of the cone-scale growth in the Abietineae, often 

 appearing in section as an outgrowth of the base of the massive inverted and fused 

 ovule, new possibilities of wing-development are opened up, as the abscission-line 

 of the fused ovule cuts a new path along the cone-scale surface to extend along the 

 intercalated region as a secondary slip of ' wing '-material. From the preceding 

 restriction of the ovules to 2 per scale, symmetrically placed, it follows that the area 

 of the free cone-scale surface may be equally divided between the 2 seeds, giving 

 each a unilateral wing, the length and breadth of which are controlled by the growth- 

 capacity of the cone-scale. An effective spinning wing is thus attained in a wholly 

 secondary manner, which compares in efficiency with the spinning wing of any other 

 fruits or seeds of Angiosperms ; the effect being intensified by the sclerosed texture 

 of the tissue, as correlated with the weight and pointed apex of the seed. Length of 

 wing, as giving the radius of the spinning circle, strength of the anterior margin, and 

 weight of the seed, are important factors, resulting (Pinus sylvestris] in the attainment 



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