112
WILLIAM MACNAE
E. Beaward nvicennia fringes
Along most coasts on which mangroves occur the most seaward
zone of trees is made up of a pure stand of one or other of two or three
species of Avicennia.
There has been a considerable confusion over the identity of several
species of Avicennia* and the latest revision by Moldenke (1960),
although helpful, does not completely disentangle the confusion.
Moldenke presents no evidence that he has seen the trees in the field.
Most of the confusion that exists concerns the species which occupy
the seaward fringes. Watson (1928) has shown that in Malaya Avicennia
alba and A. murina (= A . intermedia) occupy different sectors of this
fringe (Fig. 25). After having seen several mangals in Malaya and
South East Asia I accept and can confirm Watson’s observations-but
there are difficulties! Normally these two species are readily distinguishable-A. albu with pointed leaves and whitish reverse being quite
easily separable from A. marina with bluntly tipped leaves and yellowish reverse. However, where they overlap there are intermediates.
* I n the preparation of this review the taxonomy of the genus Avicennia has presented
many difficulties.
I n the most recent revision of the genus Moldenke (1960) recognizes six species in the
Indo-west-Pacific. These are A . alba Bl., A . balanophora Moldenke, A. eucalyptifolia
Zipp. ex Miq., A . Zanata Ridl., A . marina (Forsk.) Vierh., and A . oficinalis L. Of these
A . balanophora need not concern us for it i s recorded only from a few localities in
Queensland. Bakhuizen van der Brink (1921) recognized only two species, A . marina
and A . offccinalis. (Ridley’s (1920) description of A . Zanata, known only from the mainland of Malaya, would seem to have appeared too late for Bakhuizen’s consideration.)
These are in fact the only taxonomic studies on this genus. To both Moldenke and
Bakhuizen, A . marina is a polytypic species but to each author it differs in extent. Both
accept that the typical variety is an African and western Indian Ocean form, and that
the var. resinijera is south-eastern in distribution from New Guinea to New Zealand.
Both acccpt the var. rumphiana as representing the species in Malaysian landward
fringes. But this variety is clearly difficult. Moldenke recognized one specimen (Watson
and Burkill, 3795, 9.viii.l918) both as A . Zanata and as A . marina var. rumphiana.
Should these, then, be synonymous? Moldenke considers that Bakhuizen’s var. intermedia Griff. is the typical form of A . marina. I would concur.
Bakhuizen considered A . alba to be a , variety of A . marina; Moldenke considers it to
have specific status. The two rarely overlap ecologically, and so behave as good species.
Intermediates occur, possibly these are hybrids. Moldenke (1958) has recorded that
hybridization may occur in American species.
Moldcnke’s A. ezicalyptifolia seems to be restricted t o the highly calcareous beaches
of coral shores-either low-wooded-island reefs of the Queensland Great Barrier or coral
shores in eastern Indonesia and the Philippines. It may, perhaps, be an ecological
variety, an ecotype of A . marina which i t closely resembles.
I n this review- I shall accept A. alba, A. lanata, A . marina and A . oficiimlis. A . lanata
and A . oficinalis are species characteristic of the landward fringes or of fresh water
dominated areas in the mangal. A . aZba and A . marina are characteristic of the seaward
fringes but have a wide tolerance (see p. 131). Of these A . marinaispolytypic with both
geographical and ccological subspecies or varieties. A . eucalyptifolia seems to me to be
an ecotype of A . marina but for the present it may best be left incertae sedis.
WILLIAM MACNAE
E. Beaward nvicennia fringes
Along most coasts on which mangroves occur the most seaward
zone of trees is made up of a pure stand of one or other of two or three
species of Avicennia.
There has been a considerable confusion over the identity of several
species of Avicennia* and the latest revision by Moldenke (1960),
although helpful, does not completely disentangle the confusion.
Moldenke presents no evidence that he has seen the trees in the field.
Most of the confusion that exists concerns the species which occupy
the seaward fringes. Watson (1928) has shown that in Malaya Avicennia
alba and A. murina (= A . intermedia) occupy different sectors of this
fringe (Fig. 25). After having seen several mangals in Malaya and
South East Asia I accept and can confirm Watson’s observations-but
there are difficulties! Normally these two species are readily distinguishable-A. albu with pointed leaves and whitish reverse being quite
easily separable from A. marina with bluntly tipped leaves and yellowish reverse. However, where they overlap there are intermediates.
* I n the preparation of this review the taxonomy of the genus Avicennia has presented
many difficulties.
I n the most recent revision of the genus Moldenke (1960) recognizes six species in the
Indo-west-Pacific. These are A . alba Bl., A . balanophora Moldenke, A. eucalyptifolia
Zipp. ex Miq., A . Zanata Ridl., A . marina (Forsk.) Vierh., and A . oficinalis L. Of these
A . balanophora need not concern us for it i s recorded only from a few localities in
Queensland. Bakhuizen van der Brink (1921) recognized only two species, A . marina
and A . offccinalis. (Ridley’s (1920) description of A . Zanata, known only from the mainland of Malaya, would seem to have appeared too late for Bakhuizen’s consideration.)
These are in fact the only taxonomic studies on this genus. To both Moldenke and
Bakhuizen, A . marina is a polytypic species but to each author it differs in extent. Both
accept that the typical variety is an African and western Indian Ocean form, and that
the var. resinijera is south-eastern in distribution from New Guinea to New Zealand.
Both acccpt the var. rumphiana as representing the species in Malaysian landward
fringes. But this variety is clearly difficult. Moldenke recognized one specimen (Watson
and Burkill, 3795, 9.viii.l918) both as A . Zanata and as A . marina var. rumphiana.
Should these, then, be synonymous? Moldenke considers that Bakhuizen’s var. intermedia Griff. is the typical form of A . marina. I would concur.
Bakhuizen considered A . alba to be a , variety of A . marina; Moldenke considers it to
have specific status. The two rarely overlap ecologically, and so behave as good species.
Intermediates occur, possibly these are hybrids. Moldenke (1958) has recorded that
hybridization may occur in American species.
Moldcnke’s A. ezicalyptifolia seems to be restricted t o the highly calcareous beaches
of coral shores-either low-wooded-island reefs of the Queensland Great Barrier or coral
shores in eastern Indonesia and the Philippines. It may, perhaps, be an ecological
variety, an ecotype of A . marina which i t closely resembles.
I n this review- I shall accept A. alba, A. lanata, A . marina and A . oficiimlis. A . lanata
and A . oficinalis are species characteristic of the landward fringes or of fresh water
dominated areas in the mangal. A . aZba and A . marina are characteristic of the seaward
fringes but have a wide tolerance (see p. 131). Of these A . marinaispolytypic with both
geographical and ccological subspecies or varieties. A . eucalyptifolia seems to me to be
an ecotype of A . marina but for the present it may best be left incertae sedis.