710 ERECT FOLIAGE STEMS. 



adhere to them by girdle-sliaped, flattened, and in part lattice-forming roots, 

 send up an erect stem with large foliage when they have reached the top of the 

 wall or the summit of the block of stone. By this time the leaves of the climbing 

 parts of the stem have fallen away. Generally, this climbing stem, the first 

 stage, as it were, can no longer be recognized as such; only the clamp-roots 

 which proceeded from it, which have meanwhile become much thickened and 

 wide-meshed, appear in a most remarkable manner like a lattice-work spread 

 out over the stone. Any one not knowing the history of development of these 

 species of fig, would think that the stems rising erectly from the top of a block 

 of stone or in the cleft of a rocky wall, had germinated in the place where 

 they rise up into the air, and had sent down from thence a net-work of aerial 

 roots enveloping the stone. This idea, which at first occurs to everyone who 

 looks at the two fig-trees faithfully represented on the left-hand side of fig. 171, 

 does not, however, correspond with the actual process of development. The 

 lattice-forming roots adhering to the stone are not sent out by the small trees 

 rising above them, but have been developed by the climbing stem which had 

 mounted up by their help, and tlien became transformed into an erect stem 

 growing freely up into the air. We must also guard against generalizing and 

 regarding all root-structures of this kind as climbing roots. In the tropics 

 there are plants whose erect stems do send down aerial roots which continually 

 ramify, and then look deceptively like lattice-forming climbing roots. 



[For further details as to climbing plants the reader is referred to H. Schenck's 

 masterly Beiträge zur Biologie und ÄnatoTnie der Lianen. Jena, 1892. Ed.] 



ERECT FOLIAGE STEMS. 



Plants with procumbent and subterranean stems preponderate in high mountain 

 and in arctic regions, whilst in these places the majority of woody stems cling 

 closely to the substratum, or are embedded in the soil. Lateral shoots rising erect 

 from the ground, of course, often spring from these main stems, but they bear 

 no foliage, or possess green leaves only at the base, and terminate in flowers. 

 They are essentially of the nature of flower-stalks or scapes, and are for the most 

 part to be regarded as floral-stems. The few flowerless, erect foliage - stems 

 which are met with in these frosty districts are all very short, usually closely 

 crowded together into a carpet, or have the form of numerous erect branchlets; 

 they seldom rise more than a span-high from the ground. The only noticeable 

 erect stems besides the type of low, woody shrubs are the culm and the her- 

 baceous stem. On passing from elevated regions down into the valley, and from 

 the arctic zone southwards, besides these forms, we meet with reeds, high shrubs 

 and trees, and still nearer the equator we .'ee the erect stems of cactiform plants, 

 bamboos, and palms. 



In tliis connection the terms caudex, culm, stalk, and trunk are used to 

 indicate the forms of erect foliage-stems standing out in the landscape, terms 



