KEY TO THE ORDERS. XX111 



I. SPADICEOUS DIVISION. 



Flowers collected on a spadix, with or without a spathe or 

 sheathing bract. Leaves sometimes net-veined. 



ARACE^E. Herbs (either flag-like marsh-plants, or terres- 

 trial,) with pungent juice, and simple or compound 

 leaves, these sometimes net-veined. Spadix usu- 

 ally (but not always) accompanied by a spathe. 

 Flowers either without a perianth of any kind, or 

 with 4-6 sepals 143 



TYPHACE.E. Aquatic or marsh plants, with linear straight- 

 veined leaves erect or floating, and monoecious 

 flowers. Heads of flowers cylindrical or globular, 

 no spathe, and no floral envelopes 144 



LKMNACK*:. Small aquatics, freely floating about 144 



NAIADACE^E. Immersed aquatics. Stems branching and 

 leafy. Flowers perfect, in spikes, generally on the 

 surface 145 



II. PETALOIDEOUS DIVISION. 



Flowers not collected on a spadix, furnished with a corolla- 

 like, or occasionally herbaceous, perianth. 



A. Perianth superior (adherent to the ovary). 



* Floivers dioecious or polygamous, regular. 



HYDROCHARIDACE^E. Aquatics. Pistillate flowers only 



above water ; perianth of 6 pieces 148 



DIOSCOREACE^E. Twiners, from knotted rootstocks. Leaves 



heart-shaped, net- veined. Pod with 3 large wings. 157 



* * Flowers perfect. 



ORCHIDACEJE. Stamens 1 or 2, gynandrous. Flowers irreg- 

 ular 149 



IRIDACE^E. Stamens 3 155 



AMARYLLIDACE^E. Stamens 6. Flowers on a scape from a 



bulb 156 



B. Perianth inferior (free from the ovary). 



ALISMACE^E. Pistil apocarpous ; carpels in a ring or head, 



leaves with distinct petiole and blade 147 



. Climbing plants, with alternate ribbed and net- 

 veined petioled leaves. Flowers dioecious 157 



