636 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



6. GAERTNERIA Medic. 



Herbaceous animals or perennials with mostly alternate, variously parted leaves; 

 heads of staminate flowers as in Ambrosia or sometimes mixed with the pistillate; 

 fertile involucre 1 to 4-flowered, 1 to 4-celled, with 1 to 4 beaks, armed with numerous 

 sharp spines in several series. 



KEY TO THE SPECIES. 



Leaves simply pinnate or simple 1. G. grayi. 



Leaves twice or thrice pinna tely dissected. 



Leaves interruptedly pinnate, with ovate or triangular 



divisions, tomentose beneath 2. G. tomentosa. 



Leaves regularly pinnate with linear to oblong divisions, 

 not tomentose beneath. 

 Annual; staminate involucres cleft below the middle.. 3. G.acanihicarpa. 

 Perennial; staminate involucres not cleft to the middle.. 4. G. tenui/olia. 



1. Gaertneria grayi A. Nels. Bot. Gaz. 34: 35. 1902. 



Franseria tomentosa A. Gray, Mem. Amer. Acad. n. ser. 4: 80. 1849, not Ambrosia 

 tomentosa Nutt. 1818. 



Type locality: "High banks of Walnut Creek, between Council Grove and Fort 

 Mann, of the Arkansas." 



Range: Kansas and Colorado to New Mexico and Texas. 



We have seen no specimens of this from New Mexico, but it was collected by 

 Griffiths at Texline, Texas, so no doubt occurs in eastern and northeastern New 

 Mexico. Valleys, in the Upper Sonoran Zone. 



2. Gaertneria tomentosa (Nutt.) A. Nels. Bot. Gaz. 34: 34. 1902. 

 Ambrosia tomentosa Nutt. Gen. PI. 2: 186. 1818. 



Franseria discolor Nutt. Trans. Amer. Phil. Soc. n. ser. 7: 507. 1841. 

 Franseria tomentosa A. Nels. in Coulter, New Man. Rocky Mount. 542. 1909 

 Type locality: "In Upper Louisiana on the banks of the Missouri." 

 Range: Montana to New Mexico. 



New Mexico: Winsors Ranch; Cleveland; Maxwell City; Mora. Waste and cul- 

 tivated ground, in the Upper Sonoran and Transition zones. 



3. Gaertneria acanthicarpa (Hook.) Britton, Mem. Torrey Club 5: 332. 1894. 

 Ambrosia acanthicarpa Hook. Fl. Bor. Amer. 1: 309. 1830. 



Franseria hooheriana Nutt.; Torr. & Gray, Fl. N. Amer. 2: 294. 1842. 



Type locality: "Banks of the Saskatchewan and Red River." 



Range: British America to Texas and California. 



New Mexico: Common throughout the State. Plains and valleys, especially in 

 cultivated and waste ground, in the Lower and Upper Sonoran zones. 



One of the commonest weeds in cultivated fields almost everywhere in the State. 

 It is often called "ragweed," but of course is very different from the true ragweed of 

 the Eastern States. 



4. Gaertneria tenuifolia (A. Gray) Kuntze, Rev. Gen. PI. 1: 339. 1891. 

 Franseria tenuifolia A. Gray, Mem. Amer. Acad. n. ser. 4: 80. 1849. 



Type locality: "Poiii Creek, between Bent's Fort and Santa Fe; also at Santa Fe," 

 New Mexico. Type collected by Fendler. 



Range: Kansas and Colorado to Texas and California, also in Mexico. 



New Mexico: Santa Fe; Raton Mountains; Clayton; Maxwell City; Albert; Kings- 

 ton; Organ Mountains; Gray; Eagle Creek. Plains and moist fields, in the Upper 

 Sonoran Zone. 



