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: 



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

 ovules. 



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



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, moncecious 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 



g Flowers many; erect plants VALERIANACEAE 878 



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

 petals. 



f Tree parasites LORANTHACEAE 344 



^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. 



