38 



OVULIFEROUS FLOW1ES. 



Fig. 23. 1, Staminate flower of Pinus. Larido. 



2, Longitudinal section of same x 3. 



which dehisce longitudinal ly* when the pollen is ripe, and which is 

 then set free, and is wafted by the wind to the ovuliferous flowers. 

 After the pollen is discharged from the anther sacs the staminate 

 flowers increase in length for a short time and then wither and drop.f 

 The ovuliferous flowers are either solitary or in small clusters on the 

 ends of young shoots of the preceding year. They arise in the 

 axils of scale-like leaves like the foliage leaves and where a leaf-bud 

 would otherwise have been formed; the seed-bearing cone is thence a 



metamorphosed shoot; it consists of an 

 axis around which the ovuliferous scales 

 are spirally arranged in the same 

 phyllotaxis as the anthers of the 

 staminate flowers, viz., T 5 S . Each scale 

 is made up of two structures, of which 

 the one that bears the ovule and seed 

 is axillary to the other, usually called 

 the bract. In several species of Abies, 

 in Abietia and Larix,| the bract and 

 ovuliferous scale are separable and the 

 former conspicuously exserted ; in Cedrus, 

 Tsuga and Picea the bract does not 



advance beyond the rudimentary state, and in Pinus it coalesces 

 entirely with the scale or soon disappears after the fertilisation of the 

 ovules. This two-fold structure also occurs in the Taxodinese, although 

 traces of the bract are quite obliterated in the ripe cone. Traces of 

 it are also discernible throughout the Cupressiiiese in the microscopic 

 anatomy of the scales. The ovules are exposed, that is, not enclosed 

 in a receptacle (ovary) as in flowering plants generally, and are in 



pairs placed at the base 

 of the scales somewhat 

 obliquely in respect of the 

 median line ; these ovules 

 arc inverted, the micropyle 

 or small opening through 

 which the pollen tubes 

 enter being turned towards 

 the base of the scale. 



In the Araucarineae 

 the general structure of 

 the AbietinesB is observ- 

 able both in the staminate 

 and ovuliferous flowers. 

 In the genus Araucaria 



* This mode of dehiscences is common throughout the Abietinere with the exception 

 of Tsuga and some species of Abies in which it is transverse. 



t It may here be noted that although two is the predominant number of pollen -sacs 

 in each anther throughout the TAXACE/E and CONIFERS, exceptions occur in the 

 Cupressinese 2 4, in Cephalotaxus and Cunninghamia 3, in Taxus 4 8, and in some 

 others. 



If a young cone a few weeks old, of any species in which the bract is exserted, 

 that is, protrudes more or less beyond the ovuliferous scale as in the common Larch 

 Larix curopcea, or the Silver Fir Abies pedinata, and ripe cones of the same species 

 be subsequently examined, it will be found that the scale has increased in size faster 

 than the bract, so much so in the case of the Larch that the bract is quite enclosed 

 within the scale ; and in the Silver Fir it is relatively much shortened. 



Fig. 24. 7, Ovuliferous flowe.r of Pinus Laricio. 8, Longitudinal 



section of same x 3. 0, dorsal 10, ventral view of scale 



and bract with ovules x 5. 



