The Geography of Phytochemical Races

5.2 Nonvascular Plants 243
present, as well as in their structure, although all compounds from this taxon were
based upon the same fundamental carbon skeleton. Compounds obtained from the
upper tidal sites were shown to be debromoisolarinterol [506], debromoaplysin
[507], α-bromocuparene [508], the ether [509], and the newly described cuparene
derivative, isolaurenisol [510]. Plants from the lowest site afforded only two compounds,
isolaurinterol [511] and allolaurinterol [512] (see Fig. 5.14 for structures
506–518). Cholesterol was identifi ed from plants collected at all sites. It is tempting
to speculate that the presence of some herbivore living at lower depths has driven
selection of a different set of compounds that serve as feeding deterrents in this part
of the alga’s range. An alternative explanation, which ought to be borne in mind with
all of these chemically differentiated populations, is that one is dealing with cryptic
species. It would be of interest to combine the study of chemicals, chromosome
structure and number, life cycle features, and, ideally, some gene-sequence studies,
on some system of this sort in order to determine how useful, or reliable, the secondary
chemistry might be.
On the basis of morphological and secondary metabolic differences, Masuda et al.
(1997c) concluded that an alga previously known as Laurencia obtusa (Hudson)
Lamouroux var. snackeyi (Weber-van Bosse) Yamada (earlier name was L. paniculata
Fig. 5.14 Compounds 506–518, more terpenes from Laurencia species