xxiv.] BOTANY. 95 



XXIV. GYMNOSPERMOUS PLANTS. 



CONIFERS AND CYC ADS. 



139. There is a small but well-known group of 

 flowering-plants that differs so much from all others 

 that it requires to be described separately. Its princi- 

 pal members are the coniferae, plants which include 

 pines, firs, larches, cedars, yews, cypresses, junipers, 

 araucarias, the wellingtonia, &c., and the cycads, 

 palm-like plants of warm or hot countries. All are 

 long-lived trees or shrubs, whose flowers have no 

 perianth, and are almost invariably produced in male 

 and female cones, consisting of scales, forming a close 

 spiral round a woody axis. They are believed to 

 have been inhabitants of the globe for a much longer 

 period than any other flowering plants. 



140. Gymnosperms resemble dicotyledons in 

 the form and germination of the embryo, which 

 however has often three or more cotyledons, in the 

 exogenous growth of their stem (Par. 56), and they 

 resemble all other flowering plants, in having stamens 

 and ovules. They differ from dicotyledons in the 

 layers of wood which are formed after the first year 

 being destitute of vessels ; in the universal presence 

 of disks with central pores on the wood-tissue ; and 

 from all other flowering plants in the peculiar structure 

 of the pollen, in the ovules not being inclosed in 

 an ovary, and in the development of the embryo. 



141. Their stamens for the most part consist of 

 one or more anther-cells without filaments, situated 

 on the under-surface of the scales of* the male cone. 

 Their pollen does not produce a tube from its inner 



