VI KEY TO THE FAMILIES. 



Class ANGIOSPERMAE. 

 Sub-class MONOCOTYLEDONES. 



Plants small, floating, with no distinction of stem and 



leaves. Lemnaceae, S3. 



Plants with normal foliage. 



Inflorence a fleshy spadix. Araceae, 52. 



Inflorescence not a fleshy spadix. 



Perianth none, or of bristles, chaflfy scales 

 or a hyaline envelope. 

 Flowers not in the axils of chaffy bracts. 

 Perianth herbaceous or none. 



Flowers solitary, axillary. Najadaceae, 16. 



Flowers in axillary or terminal 

 clusters. 

 Carpels 3 or 6, united into a 



compound ovary. Scheuchzeriaceae, 16. 



Carpels 2-5 (usually 4), separate. Potamogetonaceae, 14. 

 Perianth of bristles or chaffy scales. 

 Flowers in terminal cylindrical 



spikes. Typhaceae, 13. 



Flowers in axillary globular heads. Sparganiaceae, 13. 

 Flowers in the axils of chaffy bracts. 

 Stems mostly hollow, jointed; leaves 



2-ranked. Poaceae, 18. 



Stems solid; leaves 3-ranked. Cyperaceae, 42. 



Perianth present, the parts glume- or petal- 

 like. 

 Perianth of glume-like segments. Juncaceae, 54. 



Perianth at least in part petal-like. 



Carpels distinct. Alismaceae, 17. 



Carpels united. 

 Ovary superior. 



Flowers more or less irregular, 



surrounded by a spathe. Pontederiaceae, 53. 



Flowers regular, without a 



spathe. Liliaceae, 58. 



Ovary inferior. 



Flowers regular. Iridaceae, 66. 



Flowers irregular. Orchidaceae, 67. 



Sub-class DICOTYLEDONES. 



I. Petals Distinct to the Base or Wanting. 



A. Petals None. 



Plant parasitic on other plants and without chloro- 

 phyll. Loranthaceae, 79. 

 P , not parasitic and chlorophyll-bearing. 

 Trees or shrubs. 



Leaves opposite. Aceraceae, 159. 



Leaves alternate. 



Pistillate flowers not in aments. 



Ovary 1-celled. Ulmaceae, 78. 



Ovary 2-4-celled. Rhumnus, 161. 



Pistillate flowers in aments. 



