ANALYTICAL KEY TO THE FAMILIES OF 

 ANGIOSPERMS.* 



PREPARED BY 



DR. KARL M. WIEGAND. 



Note. — To observe the structure of the ovary, make several thin sections with 

 a sharp instrument, mount in water, and view with a lens by transmitted light, as 

 follows: 



i. Vertical medial section to show inferior or superior ovary and number of 

 ovules. 



2. Cross-section to show number of cells and placentae. 



The older ovaries, being larger, are preferable for the study of cross-sections. 



The family names in parenthesis are those of Gray's Manual. 



A Ovary inferior. 



PAGE 



b HERBS (RARELY SLIGHTLY WOODY AT THE BASE). 

 c Leaves opposite or verticillate. 



d Flowers in simple or compound umbels Araliaceae 667 



dd Flowers in involucrate heads. 



e Stamens syngenesious Compositae 913 



ee Stamens distinct. 



f Leaves punctate with resinous dots; heads white or purple 



Kuhnia in Compositae 924 

 ff Leaves not punctate. 

 g Heads greenish or yellowish, monoecious or dioecious. 



Ambrosiaceae (in Compositae) 908 



gg Heads white, purple or blue; flowers perfect Dipsacaceae 880 



ddd Flowers in neither umbels nor involucrate heads. 

 e Corolla gamopetalous; limb of calyx often minute. 

 f Stamens twice the number of the corolla lobes. 



Adoxaceae (in Caprifoliaceae) 877 

 ff Stamens as many as the corolla lobes. 



g Leaves opposite, without stipules Caprifoliaceae 869 



gg Leaves opposite, with stipules; or whorled and without stipules. 



Rubiaceae 860 

 fff Stamens fewer than the corolla lobes. 



g Flowers 1-2 ; creeping plants Linnaea in Caprifoliaceae 873 



££ Flowers many; erect plants Yaleriaxaceae 878 



ee Corolla wanting, or not markedly different from the calyx, or of separate 

 petals. 



f Tree parasites Loranthaceae 344 



ff Twining plants; leaves broadly ovate, cordate, petioled.DioscoREACEAE 281 

 fff Neither twining nor parasitic. 

 g Floating aquatics. 



* On page xxii will be found a key to the families containing dioecious species for con- 

 venience in determination when only one sex is at hand. 



