2042 A TEXTBOOK OF THEORETICAL BOTANY 



AGA VALES J 



The Agavales are a small order of Monocotyledons in which the plants 

 are perennials, with thick woody rhizomes producing stems which may 

 assume the form of a tree. The leaves are usually crowded either at the base 

 or apex of the stem. They are thick, fleshy and sometimes prickly. The 

 flowers are hermaphrodite or unisexual, mostly actinomorphic, produced in 

 much-branched panicles. The perianth segments are similar in shape and 

 consist of two whorls of three parts. There are six stamens, the anthers 

 dehiscing introrsely. The ovary may be superior or inferior with axile or 

 central placentation. The fruit may be capsule or a berry and the seeds 

 contain endosperm. 



This order was made by Hutchinson to include two families. Only one, 

 the Agavaceae, need concern us here. It was included in the Amaryllidaceae 

 by Engler. 



The Agavaceae are tropical or subtropical plants many of which are of 

 economic importance. The family is naturally divisible into five main 

 tribes, the Yucceae, Dracaeneae, Agaveae, Nolineae and the Phormieae. 



The Yucceae have woody stems, with crowded leaves which are long 

 and linear. The flowers are produced in racemes or panicles. The perianth 

 segments are free or rarely connate. There are six stamens with introrse 

 anthers, inserted in the base of the perianth. The ovary is trilocular with 

 numerous anatropous ovules forming, when mature, a capsule. The genus 

 Yucca (Fig. 1982) (Adam's Needle) contains thirty species distributed in 



Fig. 1982. — Yucca filamentosa. Developing 

 inflorescence. Cultivated. 



