6 THE PALM-STEM. 



constituting the transitions to the other forms of stems, are found in 

 Desmoneus, Rhapis flabelliformis, and Corypha frigida. 



2. The Calamoid stem (Caudex calamosus) resembles the cane-like, but is 

 distinguished by the extraordinary length. The internodes are from two to 

 six feet long, thin, apparently cylindrical, but equally obconical ; the surface 

 smooth, shining as if varnished ; of a stony hardness. The substance is not 

 firmer at the periphery than in the middle ; the vascular bundles are distri- 

 buted almost uniformly throughout the whole stem; the woody mass is 

 moderately hard, exceedingly elastic, and tough ; the external fibrous layer 

 is very thin ; the stony, hard epidermis splits off in scale-like pieces when the 

 stem is bent. This form occurs only in Calamus ; the transition to the cane- 

 like stem is through Desmoneus. 



3. The Cylindrical (Mauritia-likz) stem is remarkable for its beautifully 

 regular uniformity and smooth, round form. The internodes are pretty long 

 and cylindrical ; the leaf-scars are narrow and do not form knot-like pro- 

 jections ; the rind thin, not much affected by the action of the atmosphere, 

 often clothed with spines. The internal structure is very strongly marked ; 

 almost the whole mass consists of a weak, lax, pith-like parenchyma, in which 

 lie vascular bundles of herbaceous softness. Firm woody vascular bundles 

 are only found at the periphery in a narrow circle ; but on account of their 

 frequently considerable thickness and hardness, they form an almost impene- 

 trable layer. The external fibrous layer is mostly very thin. This form 

 occurs in Mauritia (armata, viniferd), (Enocarpus (minor, &c.), Kunthia 

 (montana), Astrocaryum (vulgare, &c.) 



4. Cocos-like stem (Caudex cocoides). This is thick, and somewhat irre- 

 gularly knotted from the closely approximated, broad leaf-scars, and fre- 

 quently shaggy with the vascular bundles of the fallen leaves and withered 

 leaf-sheaths ; often very tall. The vascular bundles are distributed almost 

 uniformly throughout the whole mass ; those situated near the periphery are 

 merely a little more closely approximated than the internal, and are rather 

 thinner than thicker than the latter. The liber-like fibrous layer is very 

 thick ; the rind thick, irregularly torn, and weathered. The ligneous bundles 

 are sometimes rather soft, as in Corypha cerifera, but also sometimes very 

 hard, as in Cocos coronata. On account of the uniform distribution of the 

 vascular bundles, the stem is nearly as hard in the middle as in the outer 

 part, and on account of the great number of bundles, it presents considerable 

 solidity. This form of stem occurs in Cocos, Leopoldinia, Syagrus, Mais, 

 Corypha ; Ehapis Jlabettiformis and Lepidocaryum gracile form the transition 

 to the cane-like stems. 



5. Stemless Palms. In some the length is so small that the plants seem 

 to be stemless. Two varieties occur. In the first the stem is abbreviated, 

 like a bulb. This is not peculiar to any special genus, but occurs in indivi- 

 dual species of the most varied genera, e. g. in Geonoma acaulis, macrostachys ; 

 Astrocaryum acaule, campestre ; Diplothemium maritimum, campestre, littorale. 



