iii KEY TO THE ORDERS 



Seeds solitary in each carpel or cavity of the ovary : endosperm 

 present. 

 Flowers spicate : styles wanting : stigmas sessile. 



Order Piperales. 98 

 Flowers axillary : styles present. 



Callitrichaceae in Order Geraniales. 192 

 Seeds numerous in each cavity of the ovary : endosperm wanting. 



Podostemaceae in Order Rosales. 15? 

 cc. Flowers monoecious or dioecious. Order Geraniales. 192 



bb. Trees or shrubs : flowers monoecious or dioecious, or polj^gamous. 

 Fruit i-seeded : seeds without tufts of hairs. 

 Ovules I or 2 in each cavity of the ovary : flowers not in heads. 

 Pistillate flowers without a calyx : ovule erect and orthotropous. 



Order Myricales. 102 

 Pistillate flowers with a calyx : ovule pendulous and anatropous. 

 Leaf -blades simple. 

 Fruit a nut or an achene. Corylaceae in Order Fagales. 103 

 Fruit a drupe. Oleaceae in Order Gentianales. 245 



Leaf-blades compound : fruit a samara. 



Oleaceae in Order Gentian.\les. 245 

 Ovules many : flowers aggregated into dense heads. 



Hamamelidaceae in Order Rosales. 157 

 Fruit many-seeded : seeds each with a tuft of hairs. 



Order Salicales. 98 

 aa. Calyx present at least in the staminate or the perfect flowers. 

 Flowers, at least the staminate, in aments, or ament-like spikes. 

 Leaf-blades simple : ovule pendulous and anatropous. 



Pistillate flowers separate at maturity : fruit a nut or an achene. 



Order Fagales. 103 

 Pistillate flowers forming aggregate fruits ; fruit drupe-like. 



Artocarpaceae in Order Urticales. 108 

 Leaf-blades pinnately compound : ovule erect and orthotropous. 



Order Juglandales. 102 

 Flowers, at least the staminate, not in aments. 

 d. Ovary superior. 



Gynoecium of i or several and distinct carpels : stigma and style 

 solitary. 

 Carpel solitary. 

 Style lateral and oblique. 



Phytolaccaceae in Order Chenopodiales. i i 

 Style axile, erect. 



Ovary neither enclosed nor seated in a hypanthium or a 

 cal5'x-tube. 

 Flowers not solitary in axils : land plants. 



Order Urticales. 108 

 Flowers solitary in axils : aquatic plants. 



Ceratophyllaceae in Order Ranales. 131 

 Ovary enclosed in or seated in a hypanthium or a calyx-tube. 

 Stamens borne under the gynoecium. 



Nyctaginiaceae in Order Chenopodiales. 118 

 Stamens borne on the hypanthium or adnate to the calyx- 

 tube. Order Thyjieleales. 219 

 Carpels several. 



