2o6o A TEXTBOOK OF THEORETICAL BOTANY 



B. Perianth rudimentary. Fruits in close heads 

 V. Phytelephantoideae 



Male flowers with rudimentary perianth and numerous stamens; 

 female flowers with perianth. Endosperm hard. Leaves pinnate. 



There is only a single genus, Phytelephas, with four species occurring in 

 America. The fruit is a berry and contains several seeds. The endosperm 



Fig. i9q8. — Phytelephas itiacrocarpa. Vegetable Ivory. 

 Fruit entire and cut in half to show the ivory-like 

 endosperm. 



is composed of a hemicellulose and is very hard (Fig. 1998). It is termed 

 vegetable ivory and is used in turning billiard balls and making buttons. 



VI. Nipoideae 



Male flowers with perianth, containing three stamens; female flowers 

 without perianth. Endocarp woody. Leaves pinnate. 



There is only one genus, Nipa, with a single tropical species, N.fniticons 

 (tig. 1999). It is a low-growing palm with monoecious inflorescences, which 

 are covered with orange-brown bracts. They spring direct from the 

 underground rhizome. Just before anthesis they become quite warm 

 from the respiration of the young flowers. Indeed these bracts look, feel 

 and smell like a rubber hot-water bottle. The fruits (Fig. 2000) are 

 woody and are combined in a dense head. Each contains a single seed. 

 The plants grow in brackish waters, sometimes forming a fringe in deep 

 mud in which the rhizomes are immersed. The fruits float at first owing 

 to occluded air but later, as the air is dissolved, they sink into the 

 mud. This plant is particularly common along the Asiatic coast from 

 Ceylon to the Philippine Islands. The old leaves are used locally for 

 thatching while the young ones are employed as cigarette paper. 



1 he Palmaceae have left fossil evidence going back as far as Eocene 

 times. In the Oligocene and Miocene periods the Palms apparently 

 extended further north than they do today, for fossil remains are common 



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