482 PART IV. CLASSIFICATION. 



SUB-CLASS I. SPADICIFLORvE. 



Inflorescence usually a spadix with a spathe, but flower some- 

 times solitary : flowers frequently unisexual, sometimes dioecious : 

 perianth, often wanting, never petaloid : anthers usually extrorse, 

 or dehiscing by pores : ovary superior. 



Cohort I. Arales. The flowers are small and numerous ; the 

 inflorescence a spadix or a panicle with thick branches, commonly 

 enclosed in a greatly developed spathe ; the bracts of the indi- 

 vidual flowers are frequently wanting ; perianth 0, or polyphyl- 

 lous ; the flowers are usually diclinous, but both kinds of flowers 

 frequently occur in the same inflorescence : gynseceum apocarpous 

 or syncarpous : the seeds have a large endosperm : the embryo is 

 straight and minute. 



Order 1. ARACE^E. Flowers monoecious or $ : perianth or 

 of 46 leaves : stamens 18, frequently coherent into a synandrium 

 in the <$ flowers : ovary inonomerous, or polymerous and multilo- 

 cular : fruit a berry : seed sometimes exal- 

 buminous. Mostly tropical. 



In many of the genera the flowers are com- 

 plete and conform to the monocotyledonous 

 type, A"n, Cn, An + n G ( n ), where n may stand 

 for 2, or 3, as in Acorus (Fig. 294), in which 

 the flowers are exactly typical. In other 

 S enera > h wever, the flowers are reduced in 

 a outer, i inner peri- various ways and degrees ; not only does the 

 3ns ' * perianth disappear, but the number of the 

 stamens and carpels is frequently diminished. 

 In many ? flowers staminodia are present, either in the typical or 

 in a smaller number. An extreme case is offered by those diclinous 

 flowers of which the <$ consists of only a single stamen (e.g. 

 Arisarum), and the ? of only one monomerous ovary. These 

 much-reduced flowers are disposed in regular order on the spadix : 

 thus in Arum (Fig. 295) the numerous $ flowers, consisting each 

 of one carpel (Fig. 295 /), are inserted on the base of the spadix ; 

 and the flowers, each consisting merely of 3-4 stamens, are 

 closely packed higher up on it (Fig. 295 a). The upper part of the 

 spadix is covered with rudimentary flowers (b, c). When, as in 

 this case, the perianth of the true flowers is wholly wanting, the 

 whole inflorescence may assume the aspect of a single flower ; but 



