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===Linospadix - the walking-stick palms - in Australia and New Guinea:===
The genus ''Linospadix'' is distributed along
most of the north-east coast of Australia and
throughout most of the island of New
Guinea. In north Australia it occurs in
Qeensland from Mcllwraith Range south
to Mission Beach, and in eastern Australia
in southern Queensland from near Gympie
south to Hastings River in northern New
South Wales. This account recognises seven
species in the genus, five in Australia and
two in New Guinea.

Species of ''Linospadix'' are commonly
known as the walking-stick palms, due to
the former utilisation of the stem for
walking-sticks. Mueller (1885) provided the first
account of the use of ''Linospadix'' species
for this purpose..."''Bacularia monostachya''
(=''Linospadix monostachya''): Eastern
Australia, extending to extra-tropical
latitudes. One of the best among small palms
for table decoration. The stems sought for
walking-sticks." The making of walking-sticks
from the stems of ''Linospadix'' has not
been practised since the years immediately
following WW2. Apart from the consumption
of fruits of both Australian and New
Guinea species by indigenous people, no
other uses for ''Linospadix'' species have been
recorded. Horticulturally, ''Linospadix''
species are not that commonly used as they are
relatively slow growing and not readily
adaptable to cultivation due to their often
specific cultural requirements of shade and
humidity. Of the species in cultivation,
''L. monostachya'' and ''L. minor'' are the most
common as they have a wider ecological
amplitude than the other species.

===Taxonomic History:===
The genus ''Linospadix'' was first described
by Wendland (1875), and included one species,
''L. monostachya''. The identity of the
genus was soon to become obscured by new
species described firstly by Beccari (1877)
and secondly by the creation of a genus,
''Bacularia'', first suggested by Mueller
(1870) and later defined by Hooker (1882).
Beccari's interpretation of ''Linospadix''
differed considerably from the original
description, and the species that he included
in his ''Linospadix'' are now known to be
species of ''Calyptrocalyx''
(= syn. ''Paralinospadix'').

The fate of ''Bacularia'' was
for it to include species that conformed to
Wendland's original description. At first,
only Australian taxa were included in
''Bacularia'', but Beccari later described a few
species also from New Guinea. This situation
continued until Burtel (1935) recognised
the inconsistencies within the suite
of taxa. He proposed a revision of
''Linospadix'', which included the
synonymisation of ''Bacularia'' under
''Linospadix'' and the creation of a new genus,
''Paralinospadix'', to account for the
New Guinea taxa that Beccari had
'inadvertently' described as ''Linospadix'' species.
Burret's revision is the currently accepted
taxonomy for ''Linospadix''.

Recently, Dowe & Irvine (1997) presented
a revision of ''Linospadix'' in Australia in
which one new species was described. The
New Guinea taxa are presently the subject
of a systematic revision (Dowe in prep. ).
and preliminary assessment indicates that
of the five species that have been described
for the island, they indeed represent only
two closely related species, and informal
synonymy is accordingly suggested. A full
account of the Linospadicinae is now being
prepared as part of the Flora Malesiana
project (Dowe & Ferrero in prep.).

===Linospadix and Its Relatives:===
''Linospadix'' (7 spp.) is included in the
subtribe Linospadicinae with four other
genera - ''Calyptrocalyx'' (20 spp.),
''Howea'' (2 spp.), ''Laccospadix'' (1 sp.) and
''Paralinospadix'' (24 spp.). Of the
Linospadicinae species, 45 are endemic to
New Guinea and the remainder to the
Moluccas (1 sp.), Australia (6 spp.) and
Lord Howe Island (2 spp.). Preliminary
phenetic and cladistic studies suggest that
''Calyptrocalyx'' and ''Paralinospadix'' are
indistinguishable from each other; ''Howea'' and
''Laccospadix'' are very close to each other
though separable; and ''Linospadix'' is
relatively isolated from the other genera by what
are perceived as the most taxonomically and
biologically important characters within the
group. If closest relatives were to be
suggested for ''Linospadix'', they would include
both ''Howea'' and ''Laccospadix'' due to
similarities in the following features:
a. the position at which the peduncular
bract is attached - it is relatively close
in the three genera
b. the peduncular bract fully encloses the
inflorescence during.development in all
three genera (not so in
''Calyptrocalyx/Paralinospadtx'')
c. floral morphology - all three genera
have staminate mowers with basi- or
subbasi-fixed. non-versatile anthers
and short filaments (dorsi-fixed
and versatile in
''Calyptrocalyx/Paralinospadix'').

===Bract attachment positions:===
The position of attachment of the
peduncular bract is one of the primary characters
that separates genera in the
Linospadicinae. In all genera, the prophyll
(lower bract on the peduncle) is attached at
the base of the peduncle: it is the position
of attachment of the peduncular bract
(upper bract on the peduncle) that differs
among genera. In
''Calyptrocalyx/Paralinospadix''
the peduncular bract is attached immediately adjacent to the
prophyll, and the developing infiorescence
becomes exposed with the distal portion
breaking through while still in immature
bud. In ''Howea'' and ''Laccospadix'',
the peduncular bract is attached about
midway between where the prophyll is attached
and the lowest flowers on the rachilla
(flower bearing portion of the infiorescence).
The peduncular bract fully encloses
the infiorescence, with the rachilla only
becoming exposed upon disintegration of
the bract, though the bract still remains attached
and is never shed. In
''Linospadix'', the peduncular bract is attached
at the extreme distal end of the peduncle,
and therefore a considerable portion of the
peduncle is exposed. As the
inflorescence develops, the rachilla remains
fully enclosed within the peduncular bract.
At, or just prior to maturity of the flowers,
the peduncular bract withers and is shed,
leaving a more or less clean scar at the base
of the rachilla.

===Other Generic Differences:===
Other generic differences that distinguish
''Linospadix'' from its relatives are not as
clear-cut as is the case with bract attachment.
For example, characters of habit
(solitary or clustering), fruit shape (globose or
elongate), and condition of the mesocarp
(fibrous or non-fibrous) and the endosperm
(homogeneous or ruminate), cannot be used
with certainty for taxonomic purposes.
Floral differences within the related genera
display two classes:
''Calyptrocalyx/Paralinospadix'' usually possess staminate
flowers with an extended pistillode and stamens
with dorsi-fxed, versatile anthers on
long filaments. In ''Howea'', ''Laccospadix'' and
''Linospadix'', staminate flowers lack a
pistillode or it is only small, and stamens
have basi-fixed to subbasi-fixed, non-versatile
anthers on short filaments. These last
three genera are further distinguished by the
condition of the endosperm - it is homogemous in
''Howea'' and ''Linospadix'', and ruminate in
''Laccospadix'' - and the position of
attachment of the peduncular bract is as
described above.

===Ecology:===
All species of Linospadix occur in moist
closed forests that lack a significant seasonal
dry period. Rainfall is above 1200 mm
and as high as 10000 mm per annum in some
of these forests. In Australia, the genus occurs
from sea-level up to 1600 m altitude;
in New Guinea, it is most common at 200-1000
m altitude, and uncommon at 0-200
m and above 1000 m altitude. Very little is
known about the ecology of the genus,
though it has been observed that it has traits
that suggest that it is anemophilous (insect
pollinated) and that it is protandrous
(Henderson 1986). As for phenology
(periodicity of floral events), there is a
considerable period of time between staminate
anthesis (pollen shedding phase) and
pistilate receptivity on an individual
inflorescence. Preliminary observations suggest
that the lag time may be up to 12 months
for ''L. monostachya'' and at least many
months for other Australian species.
Population ecology, reproductive biology and
genetic diversity are essentially unknown
for the genus, and are areas of study that
could yield interesting results.

===Genetic description of Linospadix:===
Clustering or solitary, small, pleonanthic,
monoecious palms. Stems slender, nodes
conspicuous; internodes elongate. Leaves
bifid, or irregularly or evenly segmented;
leafbase clasping, crownshaft not developed;
petiole elongate or absent, channelled
adaxially, rounded abaxially; pinnae single
or united, apices praemorse when united.
acuminate when not united. Inforescence
protandrous, interfoliar, solitary, spicate:
peduncle elongate, erect; prophyll laterally
compressed, attached as base of peduncle.
enclosing inflorescence in bud, persistent:
peduncular bract tubular, attached at tip of
peduncle, deciduous; rachilla ca. length of
peduncle to much less. Flowers spirally arranged
in shallow pits; triads in proximal
portion, paired or solitary staminate flowers
in distal portion. Staminate flower sessile,
symmetric in bud; sepals broadly
imbricate; petals ca. twice as long as sepals,
thick, apically valvate; stamens erect, 4-20,
filaments short, anthers sagittate, subbasito
approaching basi-fixed, latrorse; pollen
elliptic, monosulcate, exine tectate, finely
reticulate; pistillode absent or small. Pistillate
flower globular, larger than the
staminate flower; sepals broadly imbricate;
petals exceeding the sepals, thickened
valvate tips; staminodes 3-6, toothlike; stigmas 3,
recurved. Fruit ellipsoid, cylindri-
cal, globose or pyriform, yellow or red at
maturity; stigmatic remains apical; epicarp
smooth, striate or rugose; mesocarp fleshy,
thin, longitudinal fibres appressed to
endocarp; endocarp thin, adhering to the
seed; seed subbasally attached, raphe attached
for less than o length of seed;
endosperm homogeneous; embryo basal.
Germination adjacent-ligular. Eophyll bifid.
n = 16.

===Contributed by: ===
John Dowe (Text - from '''''Palms & Cycads''''' No. 58, Jan-Mar 1998)<br/>

[[Category:Linospadix|linospadix]]
[[Category:Palm|Linospadix_linospadix]]

Linospadix linospadix - Revision history

P>Pacsoa at 19:04, 7 August 2024

Pacsoa: 1 revision imported