EE GEL OX THE RUSSIAN FLORA. 
229 
The secondary groups liinge upon the form of the filament, which in 
many species is more or less dilated above, in others filiform. 
The larger proportion (12 species) belong to the subsection charac¬ 
terised by 4 carpella sessilia’ and ‘ filamenta filiformia.’ It includes 
some of the most variable species, as T. minus , T. elatum , T. 
fcetidum , T. majus , T. simplex, T.flavum , &c. 
By far the most stable form amongst these northern Thalictrums, 
with a wide area of distribution, appears to be the little alpine Tha- 
lictrum (T. alpinuni) ; a species extending from Canada and Green¬ 
land through Siberia and Europe to our own islands, where it occurs 
in mountain moorlands from the Shetlands to North Wales. We 
find it again in the Alps and Caucasus, and it reappears in the 
Himalaya, where, consequently, it has been described as a new species 
by Dr. Boyle, though in no way differing from the home plant. 
As, however, this species is subject to but slight variation it 
is honourably distinguished amongst its congeners by a com¬ 
parative absence of the synonyms and segregates which betoken a 
4 plastic’ nature. 
Thalictrum minus is in remarkable contrast with this species. 
Under various forms common in Britain, both on the coast and 
in subalpine and rocky districts, it extends eastward through 
Europe, Siberia, and Central Asia. It is absent from America, as 
are also our remaining species T. majus and T. flavum. In respect 
to T. minus , Begel says of the numerous forms which have been 
elevated to specific rank, that they pass so insensibly into one 
another that it is impossible to maintain them independently as 
species. The surface,' form and colour of the leaves, the form of the 
auricles of the sheathing leaf-base, and character of the inflorescence, 
are not constant, and whoever examines a rich series of specimens 
of this group must become convinced that all these characters 
vary with soil, climate and amount of exposure. The form of the 
stigma is the special character in which Dr. Begel confides as 
distinguishing this species from its allies, T. majus and T. elatum. 
It is described as oblong, broadest at the base, and obliquely adnate 
to the top of the carpel. In T. majus the stigma is flat, oval or 
circular, or even broader than long, with a cordate base; it after¬ 
wards becomes twisted so as to appear as though linear in the 
ripe fruit. 
The European forms of T. minus , are—• 
a. Jacquini. (T. collinum, Bchb., T. montanum , Wallr. et T. mon ■» 
tanum , /3. roridum , Wallr., T. minus , Gr. et Godr.) 
/3. procerum. — (T. minus , E. Bot., T. saxatile , Schl., T. sylva - 
i ticum, Koch.) 
y. nutans.—(T . nutans , Desf.) 
8. virens , Koch.— (T. majus , E. Bot., T. montanum , Wallr. a. 
virens , T. collinum , Wallr., T. ftavo-virens y Ledb., T. sibiricum , 
DC., T. saxatile , Schleich., Gr. et Godr., T. Jlexuosum , Bernh., 
T. Schweiycjeri , Sprg.) 
