FRUCTIFICATION. 45 



till they attain about half their natural size ; the seed-scales thicken 

 in such a way as to press closely one upon the other so as to leave 

 no space between them ; the weight of the cone causes a bending of 

 the short foot-stalk, so that in the autumn of the first year the 

 half-grown cone takes a sub-pendent or horizontal position which 

 remains unchanged through the winter; the pollen-tubes within the 

 ovules not having completed the fertilisation of the egg-cells also 

 cease growing. It is not till the beginning of the second summer of 

 the cone development that the pollen-tubes reach the egg-cell of the 

 embryo-sac, so that actual fertilisation does not take place till 

 twelve or thirteen months after the pollination of the ovule. After 

 this has been effected, the maturation of the cone is completed in the 

 course of the second season; the cone scales become lignified, and the 

 ovules are transformed into ripe seeds." 



It is easily conceivable that pollen wafted in large quantities by 

 the wind may fall on the ovuliferous flowers of a different species, 

 and that hybridisation would ensue to a greater or less extent where 

 different species of the same genus are growing in proximity to each 

 other. Direct evidence of hybridisation among the Coniferse is, however, 

 of the slenderest description, the number of recorded instances that have 

 come to the knowledge of the author not exceeding half-a-dozen,* and 

 from these no definite conclusions can be drawn ; they only show that 

 hybridisation has taken place between two closely allied species or 

 between geographical forms of the same species. In one instance in 

 which the cones of Abies Pinsapo had been fertilised with the pollen 

 of A. Nordmanniana the seeds were sown in a French nursery, with 

 the result that the greater part of the progeny conformed to the seed 

 parent and comparatively few plants showed intermediate characters. ' 



FRUCTIFICATION. 



AN essential distinction exists between the mature ovuliferous flowers 

 or fruits of the TAXACE^E and those of the CONIFER/E, the seeds of 

 the former being solitary and enclosed in a succulent or fleshy 

 envelope, .whilst those of the latter are numerous and enclosed by 

 ligneous separable scales ; in Juniperus only are the scales fleshy and 

 "coalesce into a berry-like fruit. 



TAXACE^E. In Taxus, the ovule after fertilisation becomes invested 

 with a fleshy envelope, -technically called an arillus, which grows from 

 below upwards, but is open at the apex. In Cephalotaxus, Torreya and 

 Ginkgo it is the testa or outer covering of the ovule that becomes fleshy, 

 the seed itself being enclosed in a hard woody shell. In Podocarpus and 

 Saxegotheea it is a part of the floral axis which bears the scales and 

 seeds that becomes fleshy ; and in the curious Tasmanian monotypic 

 Microcachrys, a connecting link between the Taxaceae and Coniferae, it 

 it is the scales of the young cones that become pulpy and highly 



* Abies Pinsapo x A. Nordmanniana, Revue Horticole, 1890, p. 231. Abies lasiocarpa x 

 A. amabilis, Silva of North America, XII. p. 126. Pinus Tliunbergii x P. densiftora, 

 Abietineen des japanischen Reichs. 83. Pinus sylvestris x P. montana, Flora helvetica, 

 XLVII. 145. Abietia Douglasi var. StandisMi, from A. DouglasiixA. pectinata, Gordon, 

 Piiietum, ed. II. p. 26. Juniptrus Kanitzii, from J. cotnmunisxj. Sabinioides (?), Kerner 

 Natural History of Plants, II. 565. A progeny from Abies Pinsapo X A. cephalonica was 

 obtained artificially by the late M. Vilmorin, of Paris (Revue Horticole, 1889, p. 115). 



