510 DEPENDENCE OF PLANT FORM ON SOIL AND CLIMATE. 



In this case, again, plants from the Alpine Garden, when compared with those 

 of the Vienna Botanic Garden, had smaller stems, leaves, and flowers. The lobes 

 of the foliage-leaves from the middle of the stem of plants from the Alpine Garden 

 were pinnate, and the pinnae were either entire or beset with two small teeth 

 on each side, near the apex. The stem had ten foliage-leaves, the four uppermost 

 of which were much reduced and served as scale-leaves for the lateral shoots 

 arising from their axils. These lateral axes were not branched, and each bore 

 only a single capitulum. There were five capitula altogether. On plants from 

 the Vienna Botanic Garden the lobes of the foliage-leaves from the middle of 

 the stem were more divided, and the pinnae were beset on each side near the 

 top with 3-0 teeth. The stem bore 25-27 foliage-leaves, of which the 6-8 upper 

 ones were much reduced in size, and functioned as scale-leaves for the lateral 

 shoots in their axils. These lateral shoots were branched, and each branch 

 terminated in a capitular inflorescence. The total number of capitula was 20-30. 



From these examples it will be seen that all the parts of plants grown in 

 the Alpine experimental garden were much hindered in their growth. The 

 foliage- and floral-leaves were smaller, the stems shorter, the number of internodes, 

 foliage -leaves, inflorescences, and flowers was diminished. The flowers were 

 relatively nearer the earth, and this was due not only to the diminished number 

 and length of the internodes of the stem, but principally to the fact that the 

 flowers sprang from the axils of the lower stem-leaves. 



Plants growing in Alpine regions derive a great advantage from these altera- 

 tions, which are chiefly produced during their development by the influence of 

 the long and bright daylight of June, July, and August. If these plants had 

 to produce the same under-structure as their fellows in the Vienna Botanic 

 Garden, 2015 metres lower down, much time would be lost, and the earliest 

 flowers would hardly open before October, at a time when the winter snow is 

 already beginning to fall. But since the number of internodes is restricted, and 

 flowers are developed from the lower stories, it is possible for the plants to blossom 

 at the end of August and beginning of September, and perhaps to ripen their 

 fruits — one of the chief aims of the plant's existence. To this modification in 

 their mode of development is also due in part the repeatedly -mentioned fact 

 that many alpine plants blossom earlier than those in lower regions. But in 

 order to avoid misunderstanding, it must be expressly stated that in not one of 

 the thirty-two perennial, nor in the biennial and annual species which blossomed 

 in the Alpine experimental garden, w^as the early flowering hereditary; con- 

 sequently these plants must be carefully distinguished from the so-called asyn- 

 gamic species, which will be spoken of in one of the last chapters in this book. 



The relation of light to the colouring matters of plants has been repeatedly 

 the subject of careful investigation. All observers agree that the amount of the 

 pigment known as anthocyanin increases and diminishes with the stronger or 

 weaker sunlight enjoyed by the parts of the plant in question, and that the 

 yellow colouring matter of flowers holds a similar relation. Chlorophyll, however, 



