SECT. II PHANER0GA]\1IA 531 



Order 3. Coniferae {^^) 



The Coniferae include conspicuous trees or shrubs with woody 

 stems. The possession of small, undivided, firm leaves, flat or needle- 

 shaped, and usually lasting for several seasons, is a common character of 

 the plants of the order ; they are thus for the most part evergreen. All 

 Conifers are profusely bi'anched, and a distinction into long and short 

 shoots is usually evident. In many cases the direction and rapidity 

 of growth of the main axis differs from that of the lateral branches. 

 This is especially seen in young individuals ; old trees are often more 

 irregular in outline. 



The absence of vessels from the xylem of young plants and from 

 the secondary wood is an anatomical characteristic (cf. p. 144). Their 

 place is taken by large tracheides with peculiar bordered pits on the 

 radial walls ; these form a very uniform wood. The majority of the 

 Coniferae have resin abundantly present in all the parts of the plant. 



The Coniferae in contrast to the Cycadinae are mostly inhabitants 

 of temperate regions, and are among the trees which approach nearest 

 to the polar regions. Within the tropics they are mostly confined to 

 mountains. 



The Coniferae are divided into two families on account of differ- 

 ences in the floral structure. 



The Taxaceae have female flowers with one or few macrosporangia ; 

 the latter are usually provided with an arillus. The flowers are usually 

 not definite cones. Mostly dioecious. 



The Pinaceae on the other hand have a number of ovules in each 

 female flower, the latter being a cone with numerous sporophylls borne 

 on an axis. Arillus not present ; usually monoecious. 



Family Taxaceae. — The plants belonging to this family are grouped in a 

 number of small genera distributed in the southern hemisphere. The most 

 important genus is Podoearpus, the numerous species of which are widely distributed 

 in temperate East Asia and in Australia and New Zealand, and also occur as stately 

 trees on the mountains of the Asiatic tropics. The female flowers are small shoots, 

 the sporophylls of which are swollen and succulent ; one or two sporophylls bear at 

 the summit a single anatropous ovule surrounded by a fleshy arillus. The male 

 flowers, which are borne on the same or on distinct individuals, are small cones 

 consisting of numerous sporophylls attached to a short erect axis. Each sporophyll 

 bears two microsporangia on the lower surface ; the microspores are provided w'ith 

 distended wings. 



Taxus haccata is tlie only European representative of the family. The Yew, 

 which is now for the most part artificially introduced, had formerly a wide distribu- 

 tion as an evergreen undergrowth in our native woods (Figs. 502, 503). Isolated 

 examples of lai-ge size occur in North and Central Germany, and it occurs as a 

 more important constituent of the vegetation in Switzerland, e.g. on the steep 

 slopes at Uetli. The Yew tree attains a lieight of 10 ni. All the branches are 

 shoots of unlimited growth. The leaves stand on all sides of the ascending main 

 shoots, but in two rows on the horizontally expanded lateral branches. They are 



