CAPSELLA BURSA-PASTORIS. 
217 
nose, and may, to fresli and vigorous nerves, give pleasurable 
excitement for a time; but when long continued, or rising still 
higher, the sensation becomes painful, e.g., the screeching in 
a parrot house, the shrill barking of small dogs, the whistling 
of boys in the street, the sharpening of a saw, &c. In most 
of these cases, however, the element of dissonance unites 
with the smarting of the sound. 
(To be continued.) 
THE LEICESTERSHIRE FORMS OF CAPSELLA 
BURSA-PASTORIS * 
BY F. T. MOTT, F.R.G.S. 
Capsella Bursa-Pastor is is one of the com¬ 
monest weeds in all parts of Europe, and has 
spread itself over at least one-tliird of the 
habitable globe. Being an annual, very hardy, 
flowering at nearly all seasons of the year, and 
ripening its seeds abundantly, it has every 
chance of perpetual hybridization, and its 
“forms” are as numerous as those of Cratcegus 
oxijacantha. Some of these forms will probably in the course 
of future ages become isolated under special conditions, 
will diverge further from the type, and will ultimately settle 
down into distinct species. At present, I do not think that any 
of the European forms can be regarded as more than varieties. 
A few of them may be fairly distinguished by certain extreme 
characters, but they are all linked together by innumerable 
intermediates, and probably no one of them would come true 
from seed sown under varying conditions. Koch, in 1843, 
made four varieties from the shape of the root-leaves. 
Jordan, in 1864, described six forms which he considered to 
be good species, distinguished partly by the leaves and partly 
by the flowers and capsules. Crepin distinguished three 
varieties by the capsules alone ; and lastly, Mr. C. P. Hob- 
kirk, now of Dewsbury, a well-known and very acute botanist, 
published in 1869 a memoir upon the genus Capsella, in 
which he admits six sub-species founded on the flowers and 
capsules only. Mr. Hobkirk has generously placed in my 
hands a copy of his memoir, from which I have derived 
* Transactions of Section D of the Leicester Literary and Philo¬ 
sophical Society. Read October 15, 1884. 
