FLOWERING PLANTS AXD FERNS OF ARIZONA ] 027 



Europe. The roots, reputed to have medicinal properties, are some- 

 times eaten as a salad. 



Propagation in this genus is partly or wholly parthenogenetic, 

 which results in the production and preservation in nature of a multi- 

 tude of closely similar but distinguishable forms. The material 

 available from Arizona is rather scanty, and the treatment here given 

 is tentative. The possible existence of a fourth species is indicated by 

 a dwarf specimen from the San Francisco Peaks {Little 4635), but the 

 material available is not sufficient for identification in the present 

 knowledge of the western species of the genus. 



Key to the species 



1. Aclienes blackish, the murications comparatively short and blunt; outer 



phyllaries ovate, appressed or erect, not recurved 1. T. lyratum. 



1. Achenes greenish or reddish; outer phyllaries reeurved-spreading (2). 



2. Achenes bright red or reddish brown, the murications toward the apex very 



sharp and comparatively long 2. T. laevigatum. 



2. Achenes greenish, the murications less acute and shorter- _ 3. T. palustre. 



1. Taraxacum lyratum (Ledeb.) DC, Prodr. 7: 148. 1838. 



Leontodon lyratus Ledeb., Fl. Alt. 4: 152. 1833. 



San Francisco Peaks, Coconino County (Knowlton 142). Green- 

 land and northern Canada south to Colorado, Utah, and northern 

 Arizona; Asia. 



2. Taraxacum laevigatum (Willd.) DC, Cat, Hort. Monsp. 149. 



1813. 



Leontodon laevigatus Willd.. Sp. PL 3: 1546. 1804. 

 Taraxacum erythrospermum Andrz. in Besser, Enum. PI. 75. 

 1822. 



Lukachukai Mountains (Apache County), Betatakin (Xavajo 

 County), Tuba, and San Francisco Peaks (Coconino County), 5.000 

 to 11.500 feet, June to August. Nova Scotia to British Columbia, 

 south to Virginia, New Mexico, and northern Arizona; naturalized 

 from Europe. 



3. Taraxacum palustre (I. Lvons) Lam. et DC, Fl. Franc. 4: 45. 



1805. 



Leontodon palustre I. Lyons, Fasc. PI. 48. 1763. 



Lukachukai Mountains, Apache County (Peebles 14379 in part", 

 probably also near Prescott and Kirkland, Yavapai County (Peibli* 

 et al., 2613, 4180). Northern Canada to Mexico; naturalized from 

 Europe, or possibly native. 



The Arizona form is the common dandelion of the United States, 

 var. rulgare (Lam.) Fernald. 



138. SOXCHFS. Sowthistle 



Coarse weedy annuals, with subentire to pinnatifid, spinulose- 

 toothed leaves and medium-sized, irregularly cymose-panicled, yellow 



heads; lower leaves usually pctioled, the upper ones sessile and 

 stronglv clasping; involucre more or less regularly graduate, the phyl- 

 laries thin, corky-thickened at base in age; achenes strongly flattened, 

 several-ribbed, not beaked; pappus copious, of soft white capillary 

 bristles. 



