580 



PART III. THE CLASSIFICATION OF PLANTS. 



The ovary is either superior or inferior, di- or tri-merous, with few 

 ovules. The fruit (with the exception of Order 7, the Salicacece) 

 becomes by abortion one-seeded, and is indehiscent : the seed has 

 no endosperm. The flowers are furnished with bracts which often 

 form investments for the fruit : their arrangement in most of the 

 orders is as follows ; in the axil of a scaly bract (the bracts being 

 arranged spirally in the amentum) is a flower (Z>) with two 

 bracteoles a and ft, in the axil of each of which is another flower 

 with two more bracteoles a' and ft' (Fig. 382). The plants are 

 trees and shrubs. 



Order 1. BfiTULACEJI. The flowers are monoecious, but in dif- 

 ferent catkins. The ? flowers have no perianth : the ovary is 

 bilocular, with two ovules : the fruit is one-seeded, indehiscent, 



.11 



s\ 



FIG. 382. Typical diagram of 

 a group of flowers in the Amen- 

 tales : d bract ; b the median 

 flower with, its bracteoles, a and 

 /3 ; j>' b" the two lateral flowers, 

 with their bracteoles -' and /3'. 



FIG. 383. A Scale from a <J catkin of 

 Alnus incana : the axillary branch adheres 

 to the scale (s), it bears four bracteoles and 

 three flowers : two of the flowers are seen 

 laterally (b' b'), the median one from above ; 

 p perianth; a stamens. B Bract (s) of a ? 

 catkin of the same plant : its axillary branch 

 bears two lateral branches, each of which 

 bears two bracteoles (v v) and one flower; / 

 the ovary; n the stigmata (magnified and 

 diagrammatic) . 



without any investment : the bract is coherent with the two or four 

 bracteoles (the bracteoles a' are always absent) to form a three- 

 or five-lobed scale, which does not adhere to the fruit. 



Alnus, the Alder. In the $ amenta three flowers with four bracteoles 

 (a, /3, 0', /3') occur in the axil of the bract, each flower having a perianth of 

 four segments, and four unbranched stamens. In the <j> amenta the median 

 flower is absent ; the four bracteoles coalesce with the primary bract (Fig. 383 B, 

 v s) to form a five-lobed woody scale which persists after the fall of the f i uit 

 which is not winged. The <? catkins are borne terminally, and the $ laterally 

 on the highest lateral branch, on the shoots of the previous year ; they are not 

 enclosed by bud-scales during the winter, and blossoming takes place before 

 the unfolding of the leaves. The leaves have usually a arrangement: in 

 A. incana, the White Alder, the leaves are acuminate and gray on the under 



