A review of dipterocarps - Center for International Forestry Research
A review of dipterocarps - Center for International Forestry Research
A review of dipterocarps - Center for International Forestry Research
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Biogeography and Evolutionary Systematics <strong>of</strong> Dipterocarpaceae<br />
other families have disappeared.’ Thus we can just ‘resign<br />
ourselves to leave the Dipterocarpaceae s.s. near the<br />
Guttiferae and Ternstroemiaceae (=Theaceae). With the<br />
Malvales or Tiliales they have very little or nothing in<br />
common.’<br />
However, with recent help <strong>of</strong> molecular techniques<br />
on two species <strong>of</strong> Dipterocarpoideae (Shorea stipularis,<br />
Anthoshorea section, and S. zeylanica = Doona<br />
zeylanica) (Chase et al. 1993), Dipterocarpaceae are<br />
placed as an outlier in the order <strong>of</strong> Malvales. Its relations<br />
with Malvales are with Bombacaceae (Bombax),<br />
Tiliaceae (Tilia), Sterculiaceae (Theobroma) and<br />
Malvaceae (Thespesia, Gossypium). This work on<br />
chloroplast plastid gene rbcL1 confirms several major<br />
lineages which correspond well with Dalgren (1975)<br />
taxonomic schemes <strong>for</strong> Angiosperms.<br />
From the serology studies <strong>of</strong> John and Kolbe (1980)<br />
and Kolbe and John (1980) the further existence <strong>of</strong> the<br />
‘Theales’ is not justified if it contains Guttifereae,<br />
Dipterocarpaceae and Ochnaceae.<br />
In other works on DNA (Tsumura et al. 1993,<br />
Wickneswari 1993) parsimony analysis <strong>of</strong> molecular<br />
data revealed three major groups which resemble<br />
conclusions drawn from the anatomy <strong>of</strong> cotyledonary<br />
nodes (Maury 1978, Maury-Lechon 1979a,b). These are:<br />
an ancient group comprising Upuna, Cotylelobium,<br />
Vatica (V. odorata which is a Sunaptea), an intermediate<br />
group comprising Dryobalanops and Dipterocarpus,<br />
and an advanced group comprising Shorea, Hopea and<br />
Neobalanocarpus.<br />
Characters Specific to Dipterocarpaceae<br />
Among the numerous characters cited in the literature<br />
there is not a single character shared by all species <strong>of</strong><br />
Dipterocarpaceae sensu lato. A detailed study is needed<br />
to verify the flower bud sepals in all species; a semiquincuncial<br />
sepal arrangement is reported in<br />
Pakaraimaea and Monotoideae (Maguire et al. 1977),<br />
while this arrangement is imbricate (=semi-quincuncial)<br />
or valvate in Dipterocarpoideae.<br />
On the contrary three biological characters exist in<br />
all species <strong>of</strong> Dipterocarpaceae sensu stricto: the stamen<br />
architecture (Kostermans 1985) and the pollen type<br />
(tricolpate grains, exine without endexine: Maury et al.<br />
1975a, b), and the absence <strong>of</strong> real post-germinative<br />
growth <strong>of</strong> cotyledons (Maury 1978, Maury-Lechon<br />
1979a, b, Maury-Lechon and Ponge 1979).<br />
26<br />
The detailed aspects <strong>of</strong> stamens were underlined by<br />
Kostermans (1985): Asian Dipterocarpaceae ‘without a<br />
single exception, have short, very much flattened, broadly<br />
(more rarely narrowly) triangular filaments, which<br />
terminate in a very short, thin, cylindrical part, which<br />
continues behind the pollen sacs as a cylindrical, <strong>of</strong>ten<br />
differently colored connectival part and <strong>of</strong>ten protrudes<br />
beyond the place <strong>of</strong> insertion <strong>of</strong> the pollen sacs, giving<br />
the impression <strong>of</strong> a sporophyllous ‘leaf’ to which the<br />
pollen sacs are attached at the interior surface. The<br />
anthers are actually dorsifixed, but they appear to be<br />
basifixed. It seems that the stamen architecture is one<br />
<strong>of</strong> the ‘old’ characteristics <strong>of</strong> Dipterocarpaceae s.s. which<br />
remained immutable (and hence defines the family, cf.<br />
Stebbins, 1974 and Melville 1983).’ (Stebbins, 1974 and<br />
Melville 1983 in Kostermans 1985).<br />
‘In Monotoideae the filaments are very long,<br />
cylindrical, thin, the 2-celled anthers are dorsally<br />
attached, versatile, there is no extension <strong>of</strong> the filament<br />
behind the pollen sacs and there is no protruding part<br />
(this is sometimes also lacking in Dipterocarpoideae,<br />
but <strong>of</strong>ten replaced by this setae). The pollen sacs <strong>of</strong><br />
Dipterocarpoideae are separately and rather loosely (not<br />
completely) tied to cylindrical dorsal connectival part;<br />
the 2 or 4 sacs are not much connected, their tips are<br />
free and pointed or very pointed; the tips have no<br />
connective tissue. C. Woon and Hsuan Keng (1979) have<br />
depicted numerous stamens <strong>of</strong> the Asiatic<br />
Dipterocarpaceae and all have the same <strong>for</strong>m. In the<br />
Monotoideae, on the contrary, the 2 pollen sacs are<br />
united at their apex (not in Marquesia) by a thick,<br />
triangular-ovoid connectival tissue’ (Kostermans 1985).<br />
Further investigation is thus needed in Asian, African and<br />
South American taxa (including the new Colombian taxon<br />
Pseudomonotes) to judge if these differences have been<br />
over-estimated.<br />
Anatomically the presence <strong>of</strong> wood resin canals and<br />
multiseriate wood rays, also characterise the Asian taxa.<br />
Chemically the presence in the resins <strong>of</strong> the Asian<br />
<strong>dipterocarps</strong> <strong>of</strong> dammaranic triterpenes and<br />
sesquiterpenes, combined with the absence <strong>of</strong><br />
monoterpenes is also common to all Asian species<br />
examined by Ourisson’s team (Bisset et al. 1966, 1967,<br />
1971, Diaz and Ourisson 1966, Diaz et al. 1966). The<br />
triterpenes derived from the skeleton ‘epoxyde <strong>of</strong><br />
squalene’ (precursor <strong>of</strong> sterols) constitute a familial<br />
feature <strong>for</strong> Dipterocarpaceae sensu stricto. The<br />
distribution <strong>of</strong> the other resin compounds (particularly