268 DR. GUSTAV RADDE ON THE VERTICAL RANGE 
DRABA RIGIDA, Willd. This species grows as low as 3500 ft. 
above sea-level, but here it takes on a special facies, due to its 
abundant leaf-development ; it is then the variety TouRNEFoR- 
TIANA, Rupr. Fl. Cauc. p. 109: I have it from the defile of Blo, 
end of June, 1876. It also occurs in very shady places on the 
rocks in the defile of Darial, and the alpine form, called BRYOIDES, 
DC., is found at lower heights, as certified by the specimens 
which Ruprecht collected on 14/26 May, 1860, at 4200 ft. The 
highest stations discovered by me are Kerigo, Kwawlas-mta, and 
Borbalo, situated above 10,000 ft. In the supplemental volume 
to his ‘Flora Orientalis; Boissier has followed the example of 
Ruprecht in treating as a variety of D. rigida the formerly 
specifically distinguished D. imbricata, C. A. Mey. This species 
or variety, as variously considered, ascends to its maximum at 
Anschabala, as given by Ruprecht, Fl. Cauc. p. 112, as 1880 
hexp.—12,013 ft. Even at 11,000 ft., on Borbalo, the little 
plants had assumed the dwarf form, flowers and pods were almost 
sessile, with a stem of 3-4 mm. [4-2 in.], and cushions of radical 
leaves. 
DRABA MOLLISSIMA, Sev. I brought this with me from Schah- 
dagh, 27 June/9 July, 1885. 
Draza INCOMPTA, Stev. Collected by Bayern at Bogos, and 
stated by Ruprecht, Fl. Cauc. p. 113, to reach its maximum 
altitude on Schah-dagh at 9300 ft. 
Draga SUPRANIVALIS, Rupr. For this I have to thank the 
kindness of the author of the species, who states (Fl. Cauc. p. 116) 
it attains its maximum at 1750 hexap.— 11,182 ft., and writes :— 
*...inter mt. Sadischi et Pizarro in rupibus fere perpendicu- 
laribus pariter super regionem nivalem." 
*DRABA ARARATICA, Rupr., =D. incompta, Ledeb. non Stev., cf. 
Fl. Cauc. p. 114. Ascends the highest of all species of Draba, 
and in company with Pedicularis araratica, Bunge. Ruprecht 
assigns to Parrot’s Ararat specimens the altitude of 2166 hexap. 
=13,840 ft. as their maximum ; they were collected 29 September, 
1829. On 9/21 August, 1871, I found this species at the height 
of 14,000 ft., not far from the solid edge of the glacier, in single, 
very reduced dwarf patches, of which very few in that year 
reached the flowering state. Flower and fruit stems attained 
hardly 10-12 cm. [4-5 in.] high, with slight hairiness, the tufts 
were scarcely 2 cm. [1 in.] high, while single roots were 15-20 
