KEY TO THE ORDERS. 



Ovules and seeds borne on the face of a bract or a scale : stigmas wanting: 



Class I. Gymnospermae. 



Ovules and seeds in a closed cavity (ovary) : stigmas present. 



Class 2. Angiospermae. 



1. GYMNOSPERMAE. Page. 

 A single order in our range. Order Pinales. i 



2. ANGIOSPERMAE. 



Cotyledon i : stem endogenous : leaf-blades typically with primary or 



secondary veins parallel. Subclass i. Monocotyledones. 



Cotyledons typically 2: stem exogenous (with rare exceptions): leaf- 

 blades netted-veined. Subclass 2. Dicotyledones. 

 1. Monocotyledones. 

 Perianth rudimentary or degenerate, the members often bristles or mere 

 scales, not corolla-like, or wanting. 

 Flowers not in the axils of dry or chaffy bracts (scales or glumes). 



Perianth of bristles or chaffy scales. Order Pandanales. 4 



Perianth fleshy or herbaceous, or wanting. 

 Fruit baccate : endosperm present. Order Arales. 72 



Fruit drupaceous : endosperm wanting. Order Naiadales. 5 



Flowers in the axils of dry or chaffy, usually imbricated, bracts (scales 



or glumes). Order Graminales. ii 



Perianth of 2 distinct series, the inner series usuall}' corolloid. 

 Gynoecium of distinct carpels. Order Alismales. 9 



Gynoecium of united carpels. 

 Endosperm mealy. Order Xyridales. 74 



Endosperm fleshy, horny or cartilaginous. 

 Ovary, and fruit, superior. 

 Inflorescence not a fleshy spadix. Order Liliales. 76 



Inflorescence a fleshy spadix subtended by a spathe. 



Order Arales. 72 

 Ovary, and fruit, wholly inferior or half-inferior. 

 Endosperm present and usually copious. 



Order Amaryllidales. 88 

 Endosperm wanting. 

 Flowers regular, monoecious or dioecious : aquatic plants. 



Order Hydkocharitales. 10 

 Flowers irregular, perfect : terrestrial or epiphytic plants. 



Order Orchidales. 90 

 2. Dicotyledones. 



A. Corolla wanting, except in the pistillate flowers ofy?^^/<7«j ( Juglandaceae). 

 a. Calyx wanting, at least in the staminate flowers. 

 b. Herbs, 

 c. Flowers mainly perfect. 



vii 



