THE STEM. 171 



Quite a different kind of stem is seen in the case of 

 the few monocotyledonous plants which form trees, 

 such as the Date or other Palms. 



They are not branched ; the long midribs of the 

 leaves replace the branches, and form a crown of foliage 

 at the summit of the column-like trunk. The surface of 

 the stem is also covered by leaf scars ; and it is easily 

 seen that it is built on totally different lines to those of 

 ordinary trees. It is like a gigantic Dandelion, in which 

 the tuft of leaves is produced every year on a new part 

 of the stem, formed above the older one. Unless the 

 leaves grow to a larger size every year, the area shaded 

 does not increase with the age of the trees. Thus, 

 these palms do not have a cambium, and do not 

 markedly increase in thickness. It is clear, that the 

 structure of a dicotyledon stem cannot be expected in 

 this case, and in fact the formation is quite different. 

 The phloem and xylem groups or nerves of the leaf 

 pass bodily into the stem, so that, when this is cut 

 across, a great number of these groups are seen 

 arranged in an irregular m.anner. Thus the stem is not 

 to be compared to an Oak or Pine, but is on a different 

 architectural plan. A thick-set grove of date palms has 

 a very close resemblance to an Egyptian temple, like 

 the Hall of Columns at Luxor ; whilst an Ash wood 

 shows a decided similarity to a Gothic cathedral, with 

 relatively slender pillars and arches intersecting above. 

 This is not surprising, as it is decidedly probable, that 

 architects have borrowed many of their ideas from the 

 trees with which they were acquainted. 



The architecture, or strengthening arrangements, of 

 herbaceous plants, both monocotyledons and dicotyle- 

 dons, shows a wonderful variety ; and the forms are 

 sometimes exceedingly beautiful. This arises from the 



