The Geography of Phytochemical Races

6.6 Ullung Island, Korea 275
Pointing in that direction is the recent study of ITS sequences in Carmichaelia,
Clianthus, Montigena, and Swainsonia, four genera that comprise Carmichaelinae
(Wagstaff et al., 1999). [Those authors provided a node-based defi nition and recommended
that the clade be recognized as subtribe Carmichaelinae.] Briefl y, their data
suggest an origin of Carmichaelinae from a North American ancestor (from Astragalinae)
with subsequent diversifi cation into several lineages, one of which was
Carmichaelia. This divergence was thought to have accompanied the increased aridity
in Australia and New Zealand during the Tertiary. Carmichaelia fi rst appears in
the fossil record in the late Pliocene Waipaoa Series (Oliver, 1928). Of interest to us
here is the fi nding that ITS information places the Lord Howe Island taxon, C. exsul,
in the midst of a group of nine species, which, interestingly, includes C. kirkii, whose
fl avonoid chemistry was commented upon above. Wagstaff et al. (1999) suggest
that dispersal to Lord Howe Island has occurred “recently,” but did not provide an
estimate of the time involved, other than to comment on the age of the island.
6.6 Ullung Island, Korea
6.6.1 Acer (Sapindaceae)
Ullung Island (or Ulleung-do) is a small, volcanic island lying in the Sea of Japan,
approximately 150 km east of Korea and 300 km west of Japan at 37°30′N, 130°50′E.
The island has an area of only about 73 km 2 and has been available for colonization
by propagules for an estimated 1.8 million years (B.-Y. Sun and Stuessy,
1998). Species belonging to 34 genera (25 families) are endemic to the island. Two
endemic members of Acer, A. okamotanum Nakai and A. takesimense Nakai, have
been examined using both micro- and macromolecular methods. Morphological
data suggest that these two species have been derived from two different ancestors.
ITS data (Cho et al., 1996) confi rm this suggestion. Acer okamotanum is thought
to be closely related to A. mono Maxim., and thus could have arisen from ancestral
stock from either Korea or Japan. A close relationship between A. takesimense and
A. pseudosieboldianum (Pax) Kom., based on morphological features, is strongly
supported by the lack of ITS sequence divergence. It is interesting to note that
Chang and Giannasi (1991), studying fl avonoids of Acer sect. Palmata, suggested
that A. takesimense and A. pseudosieboldianum might be better treated as conspecifi
c. Sun and Stuessy (1998) discuss other endemic taxa of Ullung Island.
6.6.2 Cotoneaster wilsonii (Rosaceae)
Cotoneaster wilsonii Nakai, endemic to Ullung Island, is one of the many species
of the genus that occur in eastern Asia. The fl avonoid profi le of this species consists