738 



BOTANY 



PART II 



Family 4. Palmae ( 44 ). The Palms are an exclusively tropical 

 and subtropical family, the members of which mostly attain the size of 

 trees. Their slender stem is simple and usually of uniform diameter 

 throughout ; only the African species of Hyphaene have branched 

 stems. Other forms show evident growth in thickness towards the 



base and sometimes for 

 half the height of the 

 stem ; this either depends 

 on enlargement of the 

 elements already present, 

 or to a limited extent on 

 new formation of tissues 

 when required. The leaves, 

 which are often of gigantic 

 size, form a terminal crown. 

 They are either pinnately 

 or palmately divided, the 

 division coming about by 

 the death of definite por- 

 tions of tissue in the young 

 leaf in the bud, and subse- 

 quent tearing along these 

 lines. The inflorescence 

 is in some cases terminal 

 (Mctroxylon), and the in- 

 dividual perishes with the 

 development of the fruits. 

 More often the inflores- 

 cences are axillary. When 

 young, they are enclosed 

 by a massive resistant 

 sheath, the spathe ; this 

 bursts open and permits 

 of the unfolding of the 

 simple, or more usually 



branched, inflorescence. 

 B 



The individual flowers are 

 as a rule unisexual and con- 

 structed on the ordinary mono- 

 cotyledonous type; P3+3, A 3 + 3, in the male flowers, and P3 + 3, G (3), 

 in the female flowers. In Oocos their distribution is monoecious. Fig. 820 repre- 

 sents the inflorescence of Cocos nucifera, still partly enclosed by the spathe. The 

 male flowers are crowded on the terminal branches of the inflorescence, while the 

 female flowers are considerably larger and stand singly lower down. The ovary, 

 which is here composed of three united carpels, becomes, as a rule, unilocular in 

 the fruit, since only one carpel develops further. The ripe fruits are borne 



FIG. 819. Lolium temulentum. POISONOUS. 

 (After H. SCHENCK.) 



