n6 
L. Cockayne 
so is the hybrid. Southwards from this point M. ohcordata is absent 
for a distance of about 60 miles. 
( c ) Corokia buddleioides x Cotoneaster (= C. Cheesemanii Carse). 
Corokia buddleioides hardly extends to the south of latitude 38°, 
but C. Cotoneaster ranges throughout the entire length of both 
islands, being commonest in the montane belt. The first-named is 
an erect, fairly tall bushy shrub and the latter a ball-like, extremely 
dense, wiry divaricating shrub; also in leaf and flower they differ 
widely. I have not seen the hybrid in its habitat, but Carse’s 
description 1 seems to establish its origin beyond doubt. 
(d) Cassinia fulvida x leptophylla. 
Cassinia leptophylla is absent throughout the South Island up to 
about latitude 42 0 , but C. fulvida is common throughout. Both are 
very closely related, but its yellow tomentum on the undersurface 
of the leaves gives the latter a quite different appearance. As soon 
as the species meet intermediates appear and a mixed assemblage is 
present which, if it were all that was known of the group, would 
certainly be considered a “ variable species.” From their first coming 
together the species, having crossed Cook Strait, extend in company 
along the coast through the southern part of the North Island. 
After the coastal forest is felled, and burnt, these species of Cassinia, 
and their hybrids, extend some distance inland and form that dense 
shrubland, the “tauhinu scrub,” so dreaded by farmers. Here, then, 
is a case, as suggested by Professor Henry, of the chance for hybridi¬ 
sation being enormously increased by settlement. 
4. Hybrids between species of wide range and species of com¬ 
paratively small range, and restricted habitat, which lie in the path 
of the former. 
There are 11 hybrids in this class some of which might quite 
well go into class (5). 
(a) Gaultheria oppositifolia x rupestris (= G. fagifolia Hook. f.). 
The aggregate species, G. rupestris, extends throughout the South 
Island and continues its progress through the North Island to the 
Thames Botanical Subdistrict; it also ascends to above 6000 ft. 
On the pumice soil of the Volcanic Plateau it comes into contact 
1 “The plant appears to pass by regular gradations into C. Cotoneaster 
on the one hand and C. buddleioides on the other” (see Trans. N.Z.Inst. 45 , 
p. 276, 1913). The description speaks of “ the typical form” as “ very distinct,” 
but it is difficult to see why any particular form should be more “typical” 
than any other of these intermediates. 
