FLOWERING PLAXTS AXD FERNS OF ARIZONA 367 



6. Cauline leaves numerous (30 to 80 on each stem), closely imbricate; 

 stems robust, densely leafy below, single or rarely two from a simple 



base; pedicels 2 to 4 cm. long 6. A. gracilipes. 



6. Cauline leaves fewer (usually fewer than 15 on each stem), not im- 

 bricate; stems mostly slender, not densely leafy below, one to several 

 from a simple or branched base; pedicels less than 2 cm. long (7). 

 7. Basal leaves narrowly oblanceolate, acute, entire, densely pubescent 

 with minute dendritic trichomes; pubescence of the lower part 

 of the stem closely appressed; flowering pedicels sparsely pubes- 

 cent, the fruiting pedicels arched strongly downward. 



7. A. LIGXIFERA. 



7. Basal leaves broadly oblanceolate to broader, obtuse, at least the 

 lower ones dentate to repand, pubescent with coarse, dendritic, 

 simple or branched trichomes; pubescence of the lower part of 

 the stem spreading, coarse; flowering pedicels glabrous, the fruit- 

 ing pedicels widely spreading (8). 

 8. Pubescence of the basal leaves dendritic, not setaceous; leaf mar- 

 gins not ciliate; upper cauline leaves usually pubescent; stems 

 pubescent below with dendritic spreading trichomes; seeds 



winged, uniseriate 8. A. perexxaxs. 



8. Pubescence of the basal leaves coarse, simple, or forked, setaceous; 

 leaf margins ciliate; upper cauline leaves glabrous; stems 

 hirsute below with simple trichomes; seeds narrowly winged or 

 wingless, biseriate or imperfectly so 9. A. fexdleri. 



1. Arabis glabra (L.) Bernh., Syst. Verz. Pflanz. 195. 1800. 



Turritk glabra L., Sp. PI. 66. 1753. 



Mountains of Yavapai and Gila Counties, about 6,000 feet, open 

 scrub, pinelands, grassy slopes, or rarely near streams, May to July. 

 Southern Quebec to North Carolina, central Arizona, and California; 

 Europe and Asia. 



Many European and some American botanists treat this species in 

 the segregate genus Turritis, on account of the subterete siliques and 

 yellowish flowers, but so many of the characters coincide with those 

 ordinarily attributed to Arabis that such a classification is misleading. 

 The species is certainly native in many areas of the United States, but 

 it tends to become weedy and may have been recently transported to 

 some localities. 



2. Arabis hirsuta (L.) Scop., Fl. Carn. ed. 2, 2: 30. 1772. 



Turritis hirsuta L., Sp. PI. 666. 1753. 



? Arabis ovata (Pursh) Poir. in Lam., Encvcl. Sup. 5: 557. 



1817. 

 Arabis pycnocar pa Hopkins, Rhodora 39: 112. 1937. 



Plateau and mountain areas of northern Arizona (Apache and 

 Coconino Counties), 6,000 to 9,000 feet, open slopes, under small 

 trees or shrubs, and in grassy meadows, May to July. Quebec to 

 Yukon Territory, south to Georgia, northern Arizona, and California; 

 Europe and Asia. 



A rather variable species, with several varieties present in North 

 America. 



3. Arabis drummondii A. Grav, Amer. Acad. Arts and Sci. Proc. 6: 



187. 1866. 



Arabis oxyphytta Greene, Pittonia 4: 196. 1900. 

 Arabis drummondii A. Grav var. oxyphytta (Greene) Hopkins, 

 Rhodora 39: 143. 1937. 

 Apparently rare in the plateau region of northern Coconino County, 

 7,000 to 9,000 feet, coarsely granitic or sandy soils, floor of pine 



:'m;744 c - 42 24 



