KEY TO THE ORDERS. 



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



Class 1. Gymnospermae. 

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



Class 2. Angiospermae. 



1, Gymnospermae. 



Plants growing by a single terminal bud, with pinnate leaves circinate in vernation : 

 embryo prolonged into a spiral. Order Cycadales. 



Plants growing by lateral as well as by terminal buds, with scale-like, flat or needle- 

 like leaves not circinate : embryo not prolonged into a spiral. Order Pinales. 



2, Angiospermae. 



Cotyledon 1 : stem endogenous. Subclass 1. Monocotyledones. 



Cotyledons normally 2: stem exogenous (with rare exceptions). 



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. 



Perianth fleshy or herbaceous, or wanting. 



Fruit baccate : endosperm present. Order Arales. 



Fruit drupaceous : endosperm wanting. Order Naiadales. 



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



glumes). Order Poales. 



Perianth of 2 distinct series, the inner series usually corolloid. 



Gynoecium of distinct carpels. Order Alismales. 



Gynoecium of united carpels. 



Endosperm mealy. Order Xyridales. 



Endosperm fleshy, horny or cartilaginous. 



A. Ovary, and fruit, superior. 



a. Herbs, or rarely shrubs or trees, with simple leaves : ovules 2-many 



in each cavity of the ovary, or solitary only in the case of a 



few herbs 

 Inflorescence not a fleshy spadix. Order Liliales. 



Inflorescence a fleshy spadix subtended by a spathe. Order Arales. 



b. Trees or shrubs, with pinnately or palmately compound or lobed 



leaf-blades : ovules solitary in each cavity of the ovary. 



Order Arecalbs. 



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

 Endosperm present and usually copious. 



Flowers regular : androecium not reduced. Order Amaryllidales. 

 Flowers very irregular : androecium much reduced and modified. 



Order Scitaminales. 

 Endosperm wanting. 



Flowers regular, monoecious or dioecious : aquatic plants. 



Order Hydrociiaritales. 

 Flowers irregular, perfect : terrestrial or epiphytic plants. 



Order Orchidales. 



2. Dicotyledones. 



A. Corolla wanting, except in the pistillate flowers of Juglans (Juglandaceae). 



Calyx wanting, at least in the staminate flowers, except sometimes in Casuarina 

 (Casuarinaceae). 

 Herbs. 



Flowers mainly perfect. Order Piperales. 



Flowers monoecious or dioecious. Order Euphorbiales. 



Trees or shrubs : flowers monoecious or dioecious, or polygamous. 



Leaves represented by appressed whorled scales : stems or branches loosely 

 jointed. Order Casuarinales. 



vii 



