GROUP IV. PHANEROGAMIA : ANGIOSPER1VLE : MONOCOTYLEDONES. 539 



SUB-CLASS I. SPADICIFLORJE. 



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

 times solitary : flowers frequently monosporangiate, sometimes 

 dioecious : perianth, often wanting, never petaloid : anthers usu- 

 ally extrorse, or dehiscing by pores : ovary superior. 



Cohort 1. 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 brauts 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 : gynaeceum apocarpous 

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

 straight and minute. 



Order 1. ARACE^]. Flowers monoecious or ^ : perianth or of 

 4-6 leaves : stamens 1-8, frequently coherent into a synandrium 

 in the <$ flowers ovary monomerous, or 

 polymerous and multilocular : fruit a berry : 

 seed sometimes exalbuminous. Mostly tro- 

 pical. 



In many of the genera the flowers are 

 complete and conform to the monocotyle- 

 donous type, Kin, Cii, Au + n G ( n ), where 



n may stand for 2, or 3, 



as in Acorus (Fig. 348), 



in which the flowers 



are exactly typical. In 



other genera, however, 



the flowers are reduced 



in various ways and de- 

 grees ; not only does 



the perianth disappear, 



bat 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, 

 offered by those diclinous flowers of which the consists of only 

 a single stamen (e.g. Arisarum), and the ? of only one monomerous 



FIG. 348. Flower of 

 Acorns Calamus (mag.) : 

 a outer, i inner peri- 

 anth : st stamens ; / 

 ovary. 



FIG. 349. Spadix of Arum 

 maculatum (nat. size) : / 

 macrosporangiate , a micro- 

 sporangiate, and b rudi- 

 mentary flowers; c the up- 

 per club-shaped end of the 

 spadix. 



I 



An extreme case is 



