A NEW SENECIO HYBRID 405 
Sorrento Park above the cliffs; others appeared by the roadway 
above the railway at Vico; others again near Cooliemore Harbour, 
about a furlong north of the cliffs ; some even on the summit of the 
os above Khyber Pass, 8. Jacobea in all of these stations occurring 
ose by. But the headquarters of S. albescens were along the 
rail banks and sea-banks at and near Vico sere place, and 
along the cliffs and banks by the sea to the south-westward. 
the assumption of a hybrid origin for the ntamnsdiaiek it 
seems at first rather hard to account for their peculiar absence from 
Sorrento Cliffs, where one of the parents grows in such abundance, 
and at some points within a stone’s-throw of the other parent. The 
pollen of both of the assumed parent species is equally adapted for 
wind- or insect-carriage. Cross-fertilization must have been effected 
by either agency, and it seems just as inadmissible to assume the 
winds to have blown persistently from S. Cineraria towards 
Jacobaa, as to assume the honey- — insects (bees, most ore 
to have invariably travelled in the same direction. he wind 
and the bees must have ee rl in the a. dirsetieai; 
carrying the pollen of S. Jacobea to the stigmas of S. Cineraria, 
perhaps as often as —) a the pollen of the latter species to 
the stigmas of the form And this being so, does not the absence 
. intermediates, it may rid argued, flock the cliffs where S. Cineraria 
aches its maximum, show that the suggested formation of hybrids 
Pa not really take place? If we assume, however— what has long 
since been proved for other species capable of producing freee afc 
that there is a want of reciprocity of cross-fertilization between 
of le to fertilize the ovules of S. Jacobea, 
while the pond of the latter is inert as regards the ovules of the 
former. There may be, in short, a perfectly free interchange of 
pollen between * ai species, while the fertilizing effect is quite 
one-sided. ‘The sp of the ya he should be thus 
: cere S. Cin nerart ‘8. . 
¢ 
teresting example of the disturbing influence which may be exercised 
by the introduction of a new element into 
of equilibrium. The alien Senecio Cineraria from the shores of the 
Old World sea has not merely succeeded of founding a os aoe 
vigorous and eiieoitive, an 
race in which the characters of both pa 
Whether this new race will show itself capable of self- perpetuation 
ct that it produces, though in small 
ds would suggest that it may have 
- and, should this prove so, then a new 
origin may be said to have been born 
ey Bay. 
2 "This te rf iin nat ee e of an alien Senecio from Southern 
Europe having hybridized prevent with a native species in Ireland. 
The first instance, as is well known to Irish botanists, is to be found 
