402 MR. С. BUCKNALL : A REVISION 
When I have felt compelled to adopt names differing from those hitherto 
in use, or to restore to specifie rank plants which had been reduced to 
varieties, I have only done so after the most careful consideration. 
For the sake of uniformity of treatment, all descriptions have been 
rewritten, retaining, however, the characters given by the original authors, 
and adding alternative charaeters when these have been found to vary in 
authentic specimens. But, having given a complete generic description, 
I have omitted from the specifie descriptions those characters which are 
common to all the members of the genus. 
GEOGRAPHICAL DISTRIBUTION, 
The geographical area of the genus includes almost the whole of Europe 
(except Lapland), Asia Minor, a part of Siberia, and Persia. In altitude 
it ranges from sea-level to 8000 ft., the Caucasian species (S. caucasicum, 
Bieb., and %. grandiflorum, DC.) attaining 7000 ft., and S. asperum, Lepech., 
and S. peregrinum, Ledeb., 8000 ft. S. officinale, Linn., extending from the 
west of Europe into Siberia over 74? of longitude and 24? of latitude, has 
the widest range of all. That of S. tuberosum, Linn., comes next in extent, 
but falls far short of S. officinale, extending from Spain to the Black Sea 
and from central Germany to Turkey, with a small outlying area in the 
north of England and Scotland. Reckoning from north-west to south-east, 
S. bulbosum, Schimp., S. uliginosum, Kern., S. Zeyheri, Schimp., S. ottomanum, 
Friv., S. cordatum, Waldst. & Kit, S. tauricum, Willd., S. anatolicum, 
Boiss., S. orientale, Linn., S. brachycalyw, Boiss., and S. palæstinum, Boiss., 
occupy larger or smaller areas in central and southern Europe and in Asia 
Minor, sometimes distinct and sometimes overlapping. Of these, S. pales- 
tinum reaches farthest south, to about 319 N. lat. S. armeniacum, Bucknall, 
appears to extend from Armenia to the Caucasus. ©. asperum, Lepech., 
S. caucasicum, Bieb., and А. grandiflorum, DC., are found in the Caucasian 
region, and 5. peregrinum, Ledeb., in the extreme south-east of the Caucasus 
and in Persia. S. mediterraneum, Koch, and S. floribundum, Shuttlw., occur 
only in a few spots in south-east France, and S. Gussonei, Schultz, is pro- 
bably confined to Sicily. S. pseudobulbosum, Azn., S. Bornmuelleri, Bucknall, 
S. sylvaticum, Boiss., S. sepulerale, Boiss. & Bal., and S. kurdicum, Boiss. & 
Hausskn., have as vet only been met with in small areas in Asia Minor. 
As some of the species found in the last-named region bear considerable 
resemblance to each other and to some better known species, they may be 
easily overlooked. Their areas will perhaps be extended and other species 
discovered when the botany of this large and only partially explored region 
becomes better known. As an instance of the way in which a plant may 
escape notice even in a comparatively well-known country, S. pseudobulbosum 
