386 



BUTANY 



Order IV. Principes (Palmae) 



The Palms constitute an extremely natural order. While they are mainly 

 tropical forms, several species extend into the warm-temperate zones. In the 

 Atlantic States the Palmettoes (Sabal, Chamaerops, etc.) occur, while in Ari- 

 zona and Southern California are found species of Washingtonia (Pritchardia) 

 and Erythea. All of these are Fan-palms. 



Some of the smaller Palms do not develop an erect stem, but in most of them 

 the stem forms a co.lumiiar trunk, sometimes fifty metres in height. In spite of 



em 



FIG. 360. A-C, Carex sp., plant with staminate, , and pistillate, $, inflorescence. 

 B, staminate Hower, enlarged. C, pistillate flower. D, fruits of C. Asa-Grayi 

 (x ). E, single fruit, slightly enlarged. F, akene, removed from the involucre. 

 G, section of akene ; em, embryo. H, Scirpus lacustris. I, single spikelet. 

 J, flower, enlarged. 



its size, its structure does not differ essentially from that of the typical mono- 

 cotyledonous stem, and the same is true of the roots, which are produced in 

 great numbers, sometimes from a distance above the ground. 



The formation of the trunk does not begin until the crown of leaves has 

 reached nearly its full size. Branching of the trunk, apparently a true dichot- 

 omy, occurs in the "Dom-palm" (Hyphsene) of Upper Egypt, but is absent 

 in other genera, although small lateral (adventitious ?) shoots may occur at 

 the base of the stem (Phoenix Canariensis) , In the Rattan-palms (Calamus) 



