324 Matthews— The Distribution of Plants in 
doubtless, also, the time factor is concerned, since, in general, species will 
have spread over a great part of Britain before they penetrate far into 
Perthshire. 
Although a large proportion (46-7 per cent.) of the Perthshire flora 
possesses a wide range, occupying 11-13 districts, a not inconsiderable 
number of species (159, or 21-5 per cent.) is limited to one, two, or three 
districts. The numbers, as they stand, do not illustrate that regular 
descending series, from many of wide distribution to few of restricted 
distribution, which characterizes the ‘ wides ’ of Willis’s investigations. The 
figures do not give an entirely satisfactory 4 hollow curve pattern \ For we 
have, in fact, in Perthshire a flora comprising both the common and the 
rare, and the interesting 4 question is how far this rarity may be due to recent 
arrival (we are not concerned with endemics) or to other causes. 
Now, it is well known that many of the rare species in Perthshire are 
arctic-alpines, plants of the Highland region essentially. But a larger 
number of uncommon species belong, in fact, to the Lowland region, while 
a considerable number overlap, some being predominantly Highland, others 
chiefly Lowland. Along these lines a further analysis of the flora has been 
undertaken, the results being set out in Table II: 
Table II. 
Occupyi h g. 
Widely 
Chiefly 
Entirely 
Chiefly 
Entirely 
D s\f si] c 
distributed. 
Lowland. 
Lowland. 
Highland. Highland. 
JL ULLLl J • 
I. 
Thirteen districts 
1 00 
IOO 
2. 
Twelve 
113 
113 
3- 
Eleven 
>7 
42 
• • • 
42 
4 - 
Ten 
30 
30 
5 - 
Nine 
5> 
27 
7 
34 
6. 
Eight 
>7 
20 
6 
9 
35 
7- 
Seven 
23 
10 
8 
4 1 
8. 
Six 
>) 
... 
19 
8 
9 
36 
9 - 
Five 
ft 
15 
”7 
2 
3 
27 
10. 
Four 
}) 
13 
11 
3 
4 
3 1 
11. 
Three 
>> 
7 
18 
8 
10 
43 
12. 
Two 
3 
27 
0 
11 
41 
13 - 
One district 
... 
0 
40 
0 
35 
75 
Totals 
422 
80 
103 
44 
89 
738 
Rarity 
2.2 
8.6 
11..8 
7*7 
io-6 
5-6 
4-7 
r 
9.6 
Rarity in 
Britain 
2-2 
5-2 
5-9 
7.0 
11 *3 
4.4 
3.2 
9.9 
In discriminating between common and rarer species it is only the 
number of districts occupied that is considered, and, for purposes 
general discussion, widely distributed species are taken a* 
eight or more districts. The division of the county inf Q ^ U °^ e ° CCL >pywg 
eight Highland districts has rendered necessaryv an e *tensjo n f ° W ^ anc ^ and 
of the rarer Highland element beyond the li imposed h ana ^ysis 
number of Lowland districts. ^ sma U Gr 
