712 ERECT FOLIAGE STEMS. 



wliich have arisen in tlie popular tongue, and of which everyone thinks he knows 

 the meaning; these words have also been admitted into scientific terminology, 

 although, when more closely examined, they are seen to be ill-adapted for the 

 nomenclature of erect stems. Thus there are procumbent culms, procumbent 

 caules, and procumbent tree-trunks, and it is therefore not correct to use these 

 terms for erect forms only. It has been proposed to designate the erect stem, 

 which may be compared to a post, a standard-stem (stirps polaris), prefixing 

 the word "standard" to the names of the various sorts of erect stem. The 

 names resulting from this combination would prevent any confusion, but, 

 unfortunately, they are cumbrous and unusual, and on the whole unsuited to 

 this book. For these reasons the current expressions will be still employed, 

 with, of course, the proviso that in this case they refer only to standard stems. 



The cactiform stem, especially those gigantic specimens which are natives of 

 the Mexican plains, and attain to a height of some 15 metres, might have 

 been taken as a type of a standard-stem. A group of these is represented in 

 Plate VII. on the left. They look like posts which have been driven into the 

 oTound to form the foundation for a scaifolding. But since these stems have no 

 foliage-leaves, or rather, since their leaves have been transformed into spines, so 

 that the formation of organic materials, which is usually performed by foliage, 

 has to be done by the green cortex, they cannot really be reckoned as foliage- 

 stems, and can only be mentioned here incidentally. 



The caudex (cauloTua, caudex) has the greatest claim of all the series of 

 erect foliage-bearing stems to be compared to a standard. The form seen in 

 slender palms, to which the term Caudex columnaris has been applied, standa 

 foremost in this respect. The group of " Palmyra Palms, Ceylon ", represented on 

 the accompanying Plate VIII., which is a copy of a large water-colour drawing 

 from nature by Königsbrunn, gives a clear idea of this form of caudex. As a 

 rule, the height of palms is much exaggerated ; there is a great temptation, 

 especially in the case of isolated stems, to estimate them as much higher than 

 they really are. This is on account of an optical illusion which comes into 

 play just as in the estimation of the heights of mountains. An isolated mountain 

 peak rising up abruptly is, at first sight, always thought to be higher than a 

 continuous ridge which gradually ascends in gentle slopes, although both may 

 have exactly the same elevation ; and the same thing occurs in estimating the 

 height of stems. An isolated Palmyra Palm rising from among low shrubs 

 appears to be much higher than one which is actually taller, but which grows in 

 the midst of a group of trees and whose summit only rises a little above the 

 other tree-crowns. The highest columnar caudex is shown by Ceroxylon andicola, 

 a palm growing in the Andes, of which stems are known 57 metres in length. 

 The caudex of the Cocoa-nut Palm (Cocos nucifera) attains a height of 32 metres, 

 and that of the Palmyra Palm (Borassus ßabelliformis), represented in the plate 

 VIII., 30 metres. Most other palms are lower than this, the great majority 

 never exceeding 30 metres. The so-called Dwarf Palm (Chamcerops kumilis) is 



