600 



BOTANY 



TART II 



Nordmanniana from the Caucasus (Fig. 590 Z>), A. concolor, A. balsamea, and 

 A. nobilis from N. America are in cultivation. 



Picea excelsa, the Spruce (Fig. 591), is a fine tree of pyramidal shape ; it has 

 no short shoots, and the long shoots bear on all sides pointed, quadrangular, 

 needle-shaped leaves, which on horizontal or pendulous branches stand more 

 or less erect. They live for 5-7 years, and on main shoots for 12 years. Male 

 flowers as a rule on shoots of the previous year ; on flowering they become twisted 

 into an erect position. The two pollen-sacs open by a longitudinal slit. Female 

 flowers terminal on the shoots of the previous year, usually near the summit of 



the tree. They stand erect at 



? the time of flowering. The 



ripe cones are pendulous and, 

 after setting free the seeds from 

 between the scales, fall in pieces. 

 The development of the seeds 

 is completed in one year. Picea 

 orientalis from Asia Minor, 

 Picea omorica from Serbia, and 

 Picea alba from N. America 

 are frequently cultivated. 



Larix europaea, the Larch 

 (Fig. 592), is one of the few 

 deciduous Conifers and replaces 

 its foliage annually. There is 

 a differentiation into long and 

 short shoots. The former bear 

 the narrow linear leaves on all 

 sides and continue the branch- 

 ing of the pyramidal tree, the 

 lower branches of which often 

 droop downwards. The short 

 shoots arise in the axils of the 

 leaves of the long shoots of the 

 preceding year, and bear a 

 rosette of 30-40 leaves which are 



somewhat shorter but resemble 



FIG. W2. -Larix europaea. Long shoots of the preceding thoge of the j shoots The 

 year, that on the right bearing vegetative short shoots . . . 



and that on the left male and female flowers in place of flowers occur in a position corre- 

 them. (From ENOLER and PRANTL.) spending to that of the short 



shoots. The male flowers are 



bent downwards when fully developed, and the opening of the upwardly directed 

 pollen-sacs occurs as in Abies. The erect female cones produce seed in the same 

 year. Species of Cedrus are evergreen forest trees from the Atlas Mountains, 

 Lebanon, and the Himalayas, and are grown in pleasure grounds. 



The most advanced differentiation of the vegetative organs is found in the 

 genus Pinus ; P. sylvestris, the Scotch Fir, will serve as an example (Fig. 593). 

 Young seedlings in the first or second year have long shoots bearing needle-shaped 

 leaves. On older plants this type of foliage is lost ; the needles are replaced by 

 colourless, membranous scale leaves in the axils of which stand the short shoots 

 (cf. the explanation of Fig. 593). The needles are shed in three years. The seeds 

 ripen in the second year, and are set free by the separation of the scales of the 



