The Geography of Phytochemical Races

254 6 Oceanic Islands
Compound Chemotypea H O M K OH
Cyperene nd 30.8b Table 6.1 Distribution of sesquiterpene derivatives in populations of Cyperus rotundas (from
Komai and Tang, 1989)
7.2 28.7 20.7
β-Selinene 18.5 trace 17.8 nd nd
Cyperotundone nd 13.1 19.4 8.8 25.0
Patchoulenyl acetate nd trace trace 8.0 trace
Sugenyl acetate nd trace trace 6.9 trace
Patchoulenone trace nd trace nd nd
a See text for description. “OH” is the O-type found in the Hawaiian Islands.
b Values are percentage total GLC peak area; nd = not detected.
An interesting situation surrounds the H-type on the Island of Hawaii. Komai and
Tang (1989) suggested that the similarity of the H-type from the Island of Hawaii and
from Japan point to a relatively recent arrival on the Hawaii Island; although they do
not offer an estimate of the time involved. Owing to the high tourist density in the area
of active volcanism on the Island of Hawaii, it would not be surprising that propagules
could have been transported there by that route. It would be of interest to reexamine
this situation on the island at the present time, especially in light of the very extensive
volcanic disturbance in the Kalapana area over the past several years.
6.2.3 Hesperomannia (Asteraceae)
As recorded in the Manual of the Flowering Plants of Hawaii (Wagner et al., 1990,
pp. 323–326), Hesperomannia (Asteraceae: Vernonieae) comprises three species,
two of which H. arborescens A. Gray and H. arbuscula Hillebr. are listed as endangered,
while the third, H. lydgatei C. Forbes, is described as being vulnerable. The
only information on secondary metabolites of Hesperomannia of which the author
is aware of is the presence of an array of common fl avonoids in H. arborescens:
quercetin 3-O-glucoside, 3-O-glucuronide, and 3-O-rutinoside (Bohm and Stuessy,
1995), and the fl avanone eriodictyol 7-O-glucoside (Bohm, unpublished data).
These compounds are so widespread in the plant kingdom, and indeed in Asteraceae
(Bohm and Stuessy, 2001), that their presence in this species offers no clue to the
possible evolutionary relationships.
Some insights into relationships of Hesperomannia did come from macromolecular
studies by H.-G. Kim et al. (1998) whose work, based on the chloroplast ndhF
gene, suggested that the closest affi nity of the genus was among African members
of Vernonia, and that the time of divergence lies in the range 14–27 million years.
This length of time would be suffi cient for ancestors to have moved from Africa,
likely through the availability of stepping stones, to islands in the Pacifi c. No likely
intermediate taxa are known, however. The fl avonoids of H. arborescens are of such
general nature that they do not help in sorting out relationships.