laminae (' mucro') may constitute a 'pollen-collecting brush', still more or less 

 efficient, as in Sequoia, Pseudoisuga, Larix, Abies, Araucaria. 



In later phases, the carpellary scale (left as the bract-scale) is wholly superseded 

 by the cone-scale, 1 and remains as the merest relic, even at the pollination-period 

 (Pinus, Cedrus, Picea), to be further lost to sight in subsequent cone-development. 

 To this extent the genera among more specialized Abietineae, in which the bract-scale 

 is still functional in pollination, may be regarded as so far more primitive, though the 

 special advantage in pollen-collection may be doubtful. In the higher types of the 

 Abietineae the 'cone-scale' becomes precocious to the extent that it soon usurps 

 the place of the carpel, and shows a similar attempt at a ' mucro ' apex (Pinus) 

 Probably xerophytic protection of the ovules from the effect of wind is the first 

 essential : the attenuated points of the scales in either case may be effective in both 

 respects as tending to reduce the velocity of the air-currents near the micropyles. 



That the ovules were originally megasporangia on the upper surface of the 

 megasporophylls may be fairly assumed : the case of restriction to a symmetrical 

 pair in Abietineae follows the method of reduction from a marginal series in Cycads, 

 but does not necessarily imply a similar arrangement for all the group ; the sorus of 

 many ovules (Sequoia) may equally tend to a limiting case of reduction to one median 

 ovule only, associated with a median bundle for the leaf, as in Araucarineae ; although, 

 as noted, this never obtains in the case of the microsporangium. 



Note. Many more or less absurd theories have been promulgated at different 

 times, 2 which are based on the organization of the secondary adult cone-stage, and 

 take no account of the earlier working of the floral mechanism. Thus speculations 

 on the ' bifoliar spur ' nature of the Pine-cone scale are quite futile in view of the 

 presence of identical growths in more generalized 5-needled Pines, as also in Cedrus, 

 with full type of spur, or again in Tsuga and Picea, with no spurs at all. Specula- 

 tions beginning with Pinus, as the most complex cone of all, are of little value. 

 To introduce ideas of ' ligules ', ' arils ', ' epimatia ', in entire ignorance of what these 

 words imply in actual homology, is equally vague. 



Simpler views on the significance of the part played by the bract scale () and 

 cone-scale (<:) in floral mechanism are interesting in that they tend to mark the 

 essential divergence of types convergent in other respects ; cf. Cedrus (c) and Larix (&), 

 with tufted spurs ; Tsuga (c) and Pseudotsuga (b\ Picea (c) and Abies (b). 



VI. Cone-formation : The Conifer series may be sharply divided into two 

 main sections, according as the ovulate flower retains evidence of its older strobiloid 

 origin (Pinoids), or reduces to a limit of a single ovule (Taxoids) ; the latter case 

 passing on to an association with birds for the dispersal of the seeds, while the 

 former retains the older method of wind-dispersal with more or less ' winged ' seeds. 

 Minor irregularities in this progression, as in the small but distinct cone-construction 

 of Saxegoihea, or the bird-dispersed berry of some species of Juniperus, do not affect 

 the main question ; but are the more interesting as expressing the simultaneous 

 approach of a new problem. In both cases reduction of ovules and seed-output 

 appears antecedent to the necessarily comparatively recent utilization of bird-life, 

 which serves to further emphasize a preceding xerophytic mechanism of water-storage 

 and sclerosis. 



The original cone of the Pinoid series is thus to be regarded as a secondarily 

 adapted phyllotaxis-system of carpellary members, utilized to build a mechanism for 

 the protection of the germinating spores, the sexual prothallia during fertilization- 

 stages, and the ultimate growth of the embryo in the seed-stage. The significance 

 of these events in the life-history sufficiently expresses the fundamental importance of 



1 The term ' cone-scale ' is harmless, as the growth does constitute the essential feature of the 

 cones of higher Conifers; but ' ovuliferous scale' may introduce misconceptions. Apparently in no 

 case can the ovules be said to be initiated on such a scale, but are always axillary to begin with ; 

 the effect of ' insertion ' on the scale being due to subsequent intercalation at the base of the cone- 

 scale as it becomes predominant in later stages of cone-formation. This is more emphasized in the 

 case of Abies (sp.), in which ovules, bract-scale, and cone-scale may be conspicuously elevated on 

 a distinct new pedicel region (A. Veitchii, Pseudotsuga}. 



2 Coulter and Chamberlain (1910), p. 244. 



' VVorsdell (1900), Annals of Botany , xiv. 39. 



1O 



