FAMILIES OF FLOWERING PLANTS. 31 



CHAPTEFv V. 



Ordi !• PrinclpeH. The Palms. 



This order comprises but a single family, the Palmaceae or Palm 

 family, an extremely well marked natural group of plants, so charac- 

 teristic in their aspect that the term "palm-like'' whether applied to 

 leaf or trunk, is to most persons self-explanatory. The family con- 

 sists entirely of trees and shrubs, and is now essentially tropical in its 

 distribution, although there is geological evidence that palms were 

 found throughout the I'nited States before the glacial epoch. There 

 are about 150 genera and 1000 species, of which seven genera are 

 represented \)\ one or more s[)ecies each in the extreme Southern 

 States and in Southern California, while two, the date and cocoannt 

 p'ihiK occur spontuneously as esca|)es from cidtivation. 



The i)alm stem is one of our most typical examples of the so- 

 called endogenous structure among the Monocotyledons (See Supple- 

 ment, page 1.1). A cross-section shows no annual rings or circles of 

 wood, but a homoocneons mass of ])ith throui>h which the bundles of 

 woody til)er will be found irregularly distril)uted. Palms have no 

 true bark, but the external rind is often very hard, and difficult to cut 

 with an axe. The irrowth is from a terminal ])ud, and the leaves are 

 produced in a graceful cluster at the summit of the stem; as the lower 

 ones decay and fall off, their sheathing petioles remain, forming a 

 fibrous network. The flowers are borne in-^dense, fleshy flower clus- 

 ters to which the term njxidlx is applied; they are usually enveloped or 

 subtended l)y a large tough bract called a spathe. The flowers or 

 monoecious or dioecious, the male and female sporophylls being borne 

 separately on the same or difi'erent plants. We find in this family the 

 first well-marked floral envelope, consisting of two series (calyx and 

 corolla); it is usually leathery in texture, and green or yellow in color. 

 The stamens are from three to six; and the fruit is either a drupe or 

 stone fruit, as in the date, or a berry, as in the common cabbage pal- 

 metto of the South. 



From the economic standpoint the palms constitute the most im- 

 portant family among the monocotyledons; the trunks and leaves 

 furnish building materials; in addition to their edible fruits they yield 

 starch, sugar and oils, as well as various useful fibers; almost all the 

 species are ornamental, and many respond well to cultivation. In this 

 connection it will be profitable to examine the leading subdivision of 



