Botanical Studies (2008) 49: 393-404.

*

Corresponding author: E-mail: botanist@malesiana.com.

INTRODUCTION

As treated in The Genera of Araceae (Mayo et al.,

1997) the Schismatoglottideae comprised seven genera

(Schismatoglottis Zoll. & Moritzi, Piptospatha N.E. Br,

Hottarum Bogner & Nicolson, Bucephalandra Schott,

Phymatarum M. Hotta, Aridarum Ridley and Heteroari-

darum M. Hotta) with generic boundaries based on the

presence or absence of morphologies such as constricted

spathes, motile staminodes, thecae with horn-like or

needle-like structures, placentation and seed micropylar

appendages.

The most recent species-level revision of the tribe (Hay

and Yuzammi, 2000; Bogner and Hay, 2000) although

recognizing numerous novel species reduced the number

of genera to five by synonymizing Hetroaridarum with

Aridarum (Bogner and Hay, 200) and Hottarum with

Piptospatha (Bogner and Hay, 2000; Hay and Yuzammi,

2000).

In dismantling Hottarum and the subsequent transfer-

ral of the constituent species into Piptospatha (most) and

Schismatoglottis (one) placement problems arose with two

species: H. sarikeense Bogner & M. Hotta and H. lucens

Bogner. Due to their unique inflorescences and infructes-

cences, especially spathe senescence and fruit dispersal

mechanics, placement in Schismatoglottis (H. sarikeense)

and Piptospatha (H. lucens) is at best weakly supported

and our subsequent observations of plants in the wild and

in cultivation, especially noting spathe senescence me-

chanics and anther function, morphologies that, by plotting

onto recent molecular phylogenetic results, to be published

elsewhere (Wong, in prep.), are now known to be of con-

siderable significance in the tribe, has confirmed the long-

held suspicion that neither species fits unreservedly into

any pre-existing genus and that both are best accommodat-

ed in new, separate, genera. These novel genera are hereby

described and the necessary new combinations made.

Schottarum P.C. Boyce & S.Y. Wong, gen. nov.

Herba rheophytica, foliorum petiolus in vaginum su-

pra in pertem liberam triangularis persistenti productus.

Pedunculus semierectus vel patens vel declinatus. Flores

unisexuales nudi. inflorescentia femina in toto spatham

adnate. Flores masculi fertiles ad apice acicularis post-

florescentia feminiis producens. Ovula pleura, orthotropa

ad basim loculi inserta. Spadicis quam pars superior pistil-

lodiis instructa. Spathae tubus in fructiferorum inaquilatera

infundibuliformis, persistens.

Typus: Schottarum sarikeense (Bogner & M. Hotta)

P.C. Boyce & S.Y. Wong, comb. nov.

Small rheophytic herbs. Stem usually condensed (very

rarely elongated and forming a decumbent to weakly

creeping rhizome). Leaves several together; petiole,

sheathing only at extreme base and thence with a coria-

ceous persistent ligular portion; blade very narrowly ellip-

tic, thinly but somewhat stiffly coriaceous, primary lateral

veins extremely fine abaxially (barely differentiated from

secondary venation in dry material; flush with but darker

than surrounding tissue in fresh state); secondary venation

faintly prominent adaxially, fine and dense; tertiary vena-

Studies on Schismatoglottideae (Araceae) of Borneo VII:

Schottarum and Bakoa, two new genera from Sarawak,

Malaysian Borneo

Peter C. BOYCE

1,

* and Sin Yeng WONG

2

1

Malesiana Tropicals, Level 5, Tun Jugah Tower, No. 18, Jalan Tunku Abdul Rahman, 93100 Kuching, Sarawak, Malaysia

2

Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300 Samarahan, Sarawak, Malaysia

(Received November 27, 2007; Accepted May 30, 2008)

ABSTRACT.

Schottarum P.C. Boyce & S.Y. Wong and Bakoa P.C. Boyce & S.Y. Wong are described as

new genera from Sarawak, each with one species: Schottarum sarikeense (Bogner & M. Hotta) P.C. Boyce &

S.Y. Wong based upon Schismatoglottis sarikeensis (Bogner & M. Hotta) Bogner & A. Hay and Bakoa lucens

(Bogner) P.C. Boyce & S.Y. Wong based upon Piptospatha lucens (Bogner) Bogner & A. Hay. Both species

were formerly placed in now-defunct Hottarum (= Piptospatha). A key to the genera and principle subgeneric

divisions of Tribe Schismatoglottideae in Borneo is presented. Both species are illustrated.

Keyword: Araceae; Borneo; Rheophytic; Schismatoglottideae.

TAXONOMY

394

Botanical Studies, Vol. 49, 2008

tion obscure. Inflorescence solitary per shoot but plants

usually bearing several inflorescences in sequence from

separate but densely aggregated shoots; peduncle long,

stiffly arching-spreading. Spathe weakly nodding; lower

spathe narrowly ovoid, slightly down-curved, weakly

differentiated from the limb by a constriction but lower

and upper spathe differing in texture: lower spathe stiffly

coriaceous, spathe limb somewhat softly coriaceous; limb

marcescent from the margins inwards and downwards and

then, with the portion closest to the abscission layer still

fresh, the spathe limb shedding, ovate-lanceolate, spathe

slightly inflated and gaping during female anthesis, then

spreading during male anthesis, narrowed into a beaked

tip throughout. Spadix subcylindric; dorsal (in relation to

spathe) side of female zone adnate to the spathe; pistils

subglobose; stigma sessile, discoid; ovules orthotropous,

micropyle shortly beaked but not extended into an ap-

pendage; placentation basal; interpistillar staminodes

absent from among the pistils, confined to a row along the

spathe/spadix adnation and occasionally a scattered indi-

vidual amongst the two lowermost rows of pistils, sterile

interstice confined to about 2 irregular whorls of sterile

stamens at the base of the male zone; male zone rather

narrower than the female zone; stamens crowded, partially

to completely connate into groups of 2-3, truncate and flat-

topped at female anthesis with a transverse to oblique hya-

line ridge ending in an oblique disk, but at anthesis each

theca erecting this structure into a needle-like projection

terminating with a weakly peltate ovate-triangular flap;

occasionally a scattered pistillode among the stamens; ap-

pendix absent to bullet-shaped, when present comprised

on pistillodes, tapering and narrowly obtuse; distal-most

pistillodes often united to the top into curved or sinuous

groups. Fruiting spathe unequally funnel-form, the mar-

gins obliquely declined towards the convolution; fruiting

peduncle arching/declinate with lower spathe mouth held

laterally or slightly downwards with the convolution ven-

tral in respect to the peduncle; berry gibbous-cylindric to

ellipsoid-oblong,, with rather few seeds; seed ellipsoid, 1-2

mm long, 0.25-0.3 mm diam., very pale brown, minutely

scabrid, micropyle beaked but lacking a micropylar ap-

pendage.

Distribution. Malesia: endemic to Sarawak in Sarikei

and Sri Aman Districts; at both localities it is scattered and

rare.

Habitat. Old secondary and fragments of primary low-

land riparian evergreen moist forest on shales. Schottarum

is rheophytic on vertical clay-loam riverbanks. 55-80 m

asl.

Notes. The unique combination of morphologies dis-

played by Schottarum is smooth thecae with a hyaline

ridge that becomes erect into a needle-like projection at

the onset of male anthesis, an unconstricted spathe, a spa-

dix frequently with distal pistillodes and seeds lacking a

micropylar appendage and carried on a basal placenta.

Schottarum is most remarkable for the needle-like struc-

tures, tipped with a weakly peltate ovate-triangular flap,

emerging from the thecae (one per theca) only at the onset

of male anthesis. Such a structure emerging in this man-

ner is unique in the family-in all other species such thecae

structures are present from well before the inflorescence

opens and are not topped with flap of any sort. Although

yet to be confirmed by direct observation we speculate

that these flap-like structures are associated with pollen

dispersal and that a pollen droplet forms on the surface of

the flap. The very slender nature of these needle-like struc-

tures recalls those of Phymatarum although in that genus

the structures are present well before the onset of female

anthesis; further the thecae of Phymatarum are notably

verrucate (uniquely so in the tribe) while those of Schotta-

rum are smooth. Schottarum shares basal placentation with

Phymatarum but the ovules and seeds of Schottarum lack

the characteristic micropylar appendage of Phymatarum.

Basal placentation also occurs in Piptospatha but seeds

of that genus also have a pronounced micropylar append-

age; Piptospatha differs from Phymatarum in having trun-

cate stamens lacking a needle-like process.

The spadix with distal pistillodes in Schottarum i s

unique for the tribe; in all other Schismatoglottideae an the

terminal part of the spadix, and an appendix, if present, is

comprised of staminodes. We ascribe the distal organs as

pistillodes based on observations of living plants where

the highly distinctive pink pistils are clearly homologous

with the structures forming the terminal part of the spadix

are quite different to the stipitate-clavate white staminodes

associated with the pistils and the interstice between the

male and female flower zones.

Schottarum spathe limb senescence mechanics is unu-

sual, although not unique, in the tribe by the spathe limb

marcescent from the margins inwards and downwards

and then, with the portion closest to the abscission layer

still fresh, the spathe is shed. Similar (but probably not

homologous) marginal marcescence occurs in the shoot-

architecturally quite different Schismatoglottis tecturata

(Schott) Engl. with only the margin marcescent and later

shedding while the greater portion of the spathe is persist-

ent, turning green and remaining more-or-less closed at

the orifice and then shedding by abscission at the insertion

of the peduncle by splitting and recurving basipetally at

maturation of the fruits.

The spathe during fruiting of Schottarum is pecu-

liar in that while it is almost certainly a splash-cup, the

margins of the persistent lowers margins do not form a

level rim but instead are obliquely declined towards the

convolutions such that we speculate that the fruits/seeds

are ejected forwards and away from the front of the cup

rather than upwards and out as is known to be the instance

in orthodox splash-cup dispersers, e.g., Aridarum. This

view is further reinforced by the fruiting peduncle being

arching/declinate thus presenting the lower spathe open-

ing laterally or downwards rather then the peduncle being

erect and the lower spathe held erect as is the situation in

Bucephalandra, Aridarum and the Piptospatha elongata

Group¡Xall orthodox splash-cup dispersers.

BOYCE and WONG ¡X Studies on Schismatoglottideae (Araceae) of Borneo

395

Etymology. The generic name honours the Aus-

trian botanist and plantsman Heinrich Wilhelm Schott

(1794-1865), one of the founding fathers of Araceae

systematics, the first monographer of the family, and the

first botanist to make careful comparative studies of aroid

inflorescences, flowers and fruits by which he created the

basis of Araceae taxonomy for succeeding generations.

A notable aspect of Schott¡¦s work was the combination

of herbarium material, living plants and fieldwork in the

study of a largely tropical plant group at a time when such

a wide-ranging approach was most unusual.

Schottarum sarikeense (Bogner & M. Hotta) P.C. Boyce

& S.Y. Wong, comb. nov. Basionym: Hottarum sari-

keense Bogner & M. Hotta, Bull. Mus. Natl. Hist. Nat.,

B, Adansonia 5 (1983) 27, Pl. 1-3; Mayo et al., Genera

of Araceae (1997) 188, Pl. 51, F-J.¡XType: Malaysia,

Sarawak, Sarikei Division, near Sarikei, Sept. 1978, J.

Bogner 1553 Cult. Botanischer Garten Munchen (holo -

type: KYO; isotype: K, M, P, US). Figures 1 and 2

Synonym: Schismatoglottis sarikeensis (Bogner & M.

Hotta) A. Hay & Bogner, Telopea 9(1): 100 (2000).

Small rheophytic herbs up to c. 20 cm tall. Stem con-

densed (very rarely elongated and forming a decumbent

to weakly creeping rhizome), 0.5-1.2 cm diam.; roots aris-

ing adventitiously from the lower parts of an otherwise

erect stem (rarely arising along the length of a decumbent

rhizome) Leaves several together, spreading to arching;

petiole 6-12 cm long, slender, adaxially canaliculate es-

pecially in distal part, sheathing only at extreme base, the

wings extended into a coriaceous very narrowly triangular

persistent ligular portion 4-7 cm long, dark green tinged

red, drying brown; blade very narrowly elliptic, 10-14

cm long ¡Ñ 1-2.5 cm wide, thinly but somewhat stiffly

coriaceous, adaxially glossy dark green, paler abaxially,

the base cuneate, the apex acuminate to caudate for 1.5-3

cm; midrib abaxially prominent, adaxially flush to slightly

impressed with the lamina, with 5-6 extremely fine (barely

differentiated from secondary venation in dry material;

flush with but darker than surrounding tissue in fresh state)

primary lateral veins on each side, diverging at c. 45¢X;

secondary venation faintly prominent adaxially, fine and

dense; tertiary venation obscure. Inflorescence solitary

per shoot although plants usually bearing several inflores-

cences in sequence from separate but densely aggregated

shoots; peduncle 3-8 cm long, stiffly arching-spreading in

nature (where plants occur on vertical mud banks) but erect

in cultivated plants grown in pots. Spathe weakly nodding

by slight down-curving of lower part, 4-6 cm long; lower

spathe narrowly ovoid, slightly down-curved, deep green,

1.5-2 cm long, and in the main differentiated on colour and

texture (lower spathe stiffly coriaceous, spathe limb some-

what softly coriaceous) from the limb and weakly differ-

entiated by a constriction; limb pale to mid-pink or less

often white, caducous, ovate-lanceolate, spathe slightly

inflated and gaping during female anthesis, then spreading

during male anthesis, narrowed into a beaked tip through-

out, during late anthesis limb marcescent from the margins

inwards and downwards and then, with the portion closest

to the abscission layer still fresh, the spathe limb shedding.

Spadix subcylindric, 3-3.5 cm long; female zone 1-1.2 cm

long, dorsal (in relation to spathe) side of female zone ad-

nate to the spathe, c. 5 mm diam.; pistils gibbous-cylindric

to ellipsoid-oblong, c. 1 mm diam.; stigma sessile, discoid,

c. 1 mm diam. and slightly overtopping the ovary, papil-

late at anthesis, deep pink; interpistillar staminodes absent

from among the pistils, confined to a row along the spathe/

spadix adnation and occasionally a scattered individual

amongst the two lowermost rows of pistils, stipitate,

weakly clavate, slightly exceeding the pistils, white; sterile

interstice confined to about 2 irregular whorls of sterile

stamens at the base of the male zone, white; male zone

c. 1 cm long, rather narrower than the female zone, c. 3

mm diam.; stamens crowded, rather irregular in shape and

size, ellipsoid to dumbbell-shaped from above, c. 0.5 mm

across, partially to completely connate into groups of 2-3,

truncate and flat-topped at female anthesis but at anthesis

each theca extending a needle-like projection c. 2 mm long

and terminating with a weakly peltate ovate-triangular

flap through which pollen is extruded; occasionally a scat-

tered deep pink pistillode among the stamens; appendix

absent to bullet-shaped, basally isodiametric with top of

male zone, distally tapering and finally narrowly obtuse,

up to c. 0.5 cm long; pistillodes of appendix columnar, flat

topped, faintly impressed, c. 0.5 mm diam., often united

to the top into curved or sinuous groups, mid-deep pink -

very small inflorescences with spadix fertile to the apex

and pistillodes absent. Fruiting spathe unequally funnel-

form, c. 1.5-2 cm long, c. 1 cm wide across the mouth, the

margins obliquely declined towards the convolution; fruit-

ing peduncle arching/declinate with lower spathe mouth

held laterally or slightly downwards with the convolution

ventral in respect to the peduncle; berry gibbous-cylindric

to ellipsoid-oblong, 1-1.8 mm long, 1-1.5 mm diam., with

rather few seeds, mid-green with stigmatic remains dull

brown and just overtopping the ovary; seed ellipsoid, 1-2

mm long, 0.25-0.3 mm diam., very pale brown, minutely

scabrid, lacking a micropylar appendage.

Distribution. As for genus.

Habitat. As for genus.

Notes. The leaf venation is remarkable for the extreme

reduction of the primary venation so that it is almost not

differentiated from the secondary; indeed the primary

veins are virtually impossible to recognise in the dry plant.

The collection cited below from Sri Aman (P.C. Boyce

et al. AR-1161) is an interesting extension to the known

range of Schottarum. It was collected sterile and in leaf

form and general shoot architecture matches S. sarikeense

it has a stem forming a creeping rhizome producing stout

roots from the leaf bases; such a growth habit has not been

observed at the Sarikei populations of S. sarikeeense. but

on flowering in cultivation proved to be without doubt S.

sarikeense.

396

Botanical Studies, Vol. 49, 2008

Figure 1. Schottarum sarikeense (Bogner & M. Hotta) P.C. Boyce & S.Y. Wong. A, Plant in habitat, Sarikei; B, Inflorescence at the

onset of male anthesis with the thecae horns erect; C, Side view of spathe showing the lower spathe (green); D, Inflorescence (spathe

artificially removed) showing spadix at female anthesis. Note that the needle-like structures are still flat against the thecae have yet to

become erect.

BOYCE and WONG ¡X Studies on Schismatoglottideae (Araceae) of Borneo

397

Figure 2. Schottarum sarikeense (Bogner & M. Hotta) P.C. Boyce & S.Y. Wong. A, Inflorescence at the onset of male anthesis; note

the needle-like structures associated with the stamens and the distal pistillodes; B, Inflorescence at late male anthesis. Note the spathe

limb beginning to become marcescent; C & D, Persistent lower spathe at early fruit maturity. Note the margins obliquely declined to-

wards the convolution; E, Ovary at late developmental stage. Note the basal ovules with a short micropylar beak but no appendage.

398

Botanical Studies, Vol. 49, 2008

The Sarikei habitat of Schottarum is particularly rich in

aroids, notably Bucephalandra motleyana Schott, Homa-

lomena griffithii (Schott) Hook. f., H. vagans P.C. Boyce,

Rhaphidophora elliptifolia Merr., R. lobbii Schott, R. ty-

pha P.C. Boyce, Schismatoglottis conoidea Engl., S. erecta

M. Hotta, S. jelandii P.C. Boyce & S.Y. Wong, S. josefii

A. Hay, S. motleyana (Schott) Engl. and S. tecturata. At

Batang Ai (Sri Aman) common local associated aroids

include Homalomena hostiifolia Engl., H. humilis (Jack)

Hook. f., H. insignis N.E. Br., Podolasia stipitata N.E. Br.,

Pothos barberianus Schott, Rhaphidophora beccarii Engl.,

R. megasperma Engl., Schismatoglottis ciliata A. Hay,

S. clarae A. Hay, S. conoidea Engl., S. erecta M. Hotta,

S. jipomii P.C. Boyce & S.Y. Wong, S. josefii A. Hay, S.

tecturata, Scindapsus glaucescens (Engl. & K. Krause)

Alderw., S. longipes Engl. and S. pictus Hassk.

Other specimens examined. SARAWAK: Sri Aman Di-

vision, Lubok Antu, Batang Ai, Nanga Sumpa, Sungai Pe-

dali, 01¢X11¡¦58.9"; 112¢X03¡¦27.0", 7 April 2005, P.C. Boyce

et al. AR-1161 (SAR). Sarikei Division, near Sarikei, Sept.

1978, J. Bogner 1530 (K). Sarikei, Maradong, Sungai Ma-

tob, 01¢X52¡¦06.1"; 111¢X55¡¦30.7", 8 Dec 2005. P.C. Boyce,

Wong Sin Yeng et al. AR-1609 (SAR); ibid. AR-1615

(SAR).

Bakoa P.C. Boyce & S.Y. Wong, gen. nov.

Herba rheophytica, foliorum petiolus in vaginum su-

pra in pertem liberam triangularis marcescenti productus.

Pedunculus semierectus vel patens. Flores unisexuales

nudi. Spatha spadici usque ad medium parties inflorescen-

tia mascula adnata. Staminodiis non ad apicalem partem

spadicum limitatis sed etiam in latere spathae adverso

locum florum masculinorum explantibus et partem mascu-

linam a parte feminea spadicum disjungentibus. Spathae

fructiferorum persistens spathae tum omnino marcescens et

fructus spargens.

Typus: Bakoa lucens (Bogner) P.C. Boyce & S.Y.

Wong, comb. nov.

Small rheophytic herbs. Stem condensed. Leaves sever-

al to many together; petiole sheathing only at the extreme

base, thence extended into a very narrowly triangular

marcescent ligular portion; blade very narrowly elongate-

elliptic, rather coriaceous; midrib abaxially prominent with

4-6 very fine but well-differentiated (darker than surround-

ing tissue) primary lateral veins on each side, these hardly

differentiated in thickness from the secondary venation

and diverging at c. 30¢X; secondary veins adaxially more

or less obscure, abaxially fine and rather faint, running to

a thicker marginal vein; tertiary venation forming an in-

conspicuous tessellate reticulum abaxially. Inflorescence

solitary to three together on a single shoot; peduncle erect

to arching at anthesis with the spathe slightly down-turned

and the spathe opening ventral, declinate post anthesis

and during fruiting. Spathe weakly nodding; more or less

oblanceolate, hardly constricted, with a long apiculate tip.

Spadix adnate to the spathe in the lower 1/2-2/3; female

zone completely adnate to the spathe on the dorsal side;

ovary depressed globose and weakly angular, placenta-

tion basal, ovules orthotropous, long-beaked; stigma

sessile, narrower than the ovary, button-like, papillate;

interpistillar staminodes absent from the female zone;

sterile interstice somewhat thicker than the female zone,

dorsally adnate to the spathe, composed of large truncate

mostly irregularly polygonal staminodes, these also dis-

tributed up the dorsal side of the male zone to the spadix

apex; male zone subcylindric-ellipsoid, apically narrowly

acute and sterile, basally adnate to the spathe on the dorsal

side, mostly with only the ventral-most stamens (those

exposed by gaping spathe limb) fertile, sometimes more

extensively fertile, but always sterile on the dorsal side;

stamens crowded, truncate, dumbbell-shaped to irregularly

rectangular from above, often with the connective irregu-

larly broadened on one side; thecae each opening through

a conspicuous, broad-rimmed pore. Fruiting spathe per-

sistent, at fruit maturity very swiftly drying and thence by

reflexing of the spadix the spathe recurving and opening

basally and also tearing at the peduncle insertion to expose

the fruits, at the same time spathe limb remaining distally

convolute and still clasping the spadix appendix remains;

fruiting peduncle initially declinate, later twisting through

180¢X and becoming arching-erect; berry depressed globu-

lar; seed ellipsoid, micropyle blunt, testa slightly ribbed.

Distribution. Malesia: endemic to Borneo (Sarawak &

West Kalimantan)

Habitat. Lithophytic in forest, and rheophytic near

streams or waterfalls, c. 30 m alt.

Notes. The combination of a spadix more than half ad-

nate to the spathe, fertile male flowers mostly restricted

to a small zone coincidental with the area exposed by the

gaping spathe during anthesis, a fully persistent spathe

becoming wholly marcescent at fruiting and seeds with a

blunt micropyle borne on a basal placenta is unique in the

Schismatoglottideae.

Post pollination the persistent spathe turns green and

thickens slightly while the peduncle becomes declinate,

holding the spathe with the free margins downwards; as

also occurs in Piptospatha grabowskii (Engl.) Engl. At

the onset of fruit maturity the peduncle of Bakoa twists

through 180¢X and once more becomes semi-erect, to bring

the spathe free margins to a dorsal position after which

the spathe dries and turns brown very swiftly and thence

by reflexing of the spadix the spathe recurves and opens,

tearing at the peduncle insertion to exposes the fruits while

at the same time spathe limb remains distally convolute

and clasps the remains of the spadix appendix. This is in

marked contrast to other species in the P. grabowskii group

in which at fruit maturity there is no peduncle movement

and the persistent spathe is shed while still in a fresh con-

dition seemingly to play little or no role on the dispersal

mechanics of the fruits. The fruiting mechanics of Bakoa

are unique in the tribe.

Reports that the seeds have a micropylar appendage are

erroneous. Dissection of several ripe and near-ripe fruits

demonstrates that the micropyle is blunt and the seeds are

BOYCE and WONG ¡X Studies on Schismatoglottideae (Araceae) of Borneo

399

attached to a ring-like basal placenta by a short, dark funi-

cle.

Incidentally, our observations of the stamens is not in

accordance with those of Bogner and Hay (2000) who

stated that the "stamens are more similar to those of many

Schismatoglottis¡K, having large rims to the pores and a

generally narrow connective"; all material we have exam-

ined has a wide connective.

Etymology. Bakoa is named for Bako National Park,

Kuching Division. Established in 1957, Bako is Sarawak¡¦s

oldest national park and despite its comparative small size

is an extraordinarily beautiful and rich reserve of plants

and animals.

Bakoa lucens (Bogner) P.C. Boyce & S.Y. Wong, comb.

nov. Basionym: Hottarum lucens Bogner, Pl. Syst. Evol.

142 (1983) 49, fig. 1-3; Mayo et al., Genera of Araceae

(1997) 188, pl. 51, A-E.¡XType: Malaysia, Sarawak,

Kuching Division, Bako National Park, Sg. Tajor, 19

Sep 1978, J. Bogner 1439 (holotype: K; isotype: K,

US). Figures 3, 4 and 5

Synonym: Piptospatha lucens (Bogner) Bogner & A.

Hay, Telopea 9(1): 217 (2000).

Small rheophytic herbs to c. 30 cm tall. Stem con-

densed, with stiff roots 1-1.5 mm diam. adhering strongly

to rocks Leaves several to many together; petiole (5-)6-10

cm long, 0.2-0.3 cm diam., slightly flattened adaxially,

sheathing only at the extreme base, the wings extended

into a very narrowly triangular marcescent ligular portion

3.5-6.5 cm long drying dark brown; blade very narrowly

elliptic, slightly coriaceous, 8-22 cm long ¡Ñ 1-3 cm wide,

very shiny dark green adaxially, abaxially paler, the base

cuneate, the apex narrowly acute, slightly acuminate and

tubular-apiculate for 2-3 mm; midrib abaxially prominent

with 4-6 very fine primary but well-differentiated (darker

than surrounding tissue) lateral veins on each side, these

hardly differentiated in thickness from the secondary ve-

nation and diverging at c. 30¢X; secondary veins adaxially

more or less obscure when dry but conspicuous in liv-

ing material, abaxially fine and rather faint, running to a

thicker marginal vein; tertiary venation forming an incon-

spicuous tessellate reticulum abaxially. Inflorescence soli-

tary to three together on a single shoot; peduncle 4-8 cm

long, arching to semi-erect, green; spathe weakly down-

turned. Spathe 3.5-5 cm long, more or less oblanceolate,

hardly constricted, lower part green, limb white, apiculate

for 6-8 mm, apicule green. Spadix 2.5-4 cm long, adnate

to the spathe in the lower 2/3; female zone completely

adnate to the spathe on the dorsal side, c. 1 cm long, 0.4

cm diam.; ovary depressed globose and weakly angular,

1-1.5 mm diam., light green, placentation basal, ovules

long-beaked; stigma sessile, narrower than the ovary, c.

0.4 mm diam., button-like, papillate, whitish; interpistil-

lar staminodes absent from the female zone; sterile in-

terstice robust, 6-9 mm long, somewhat thicker than the

female zone, 5-7 mm diam., dorsally adnate to the spathe,

composed of large truncate mostly irregularly polygonal

staminodes 0.8-1.5 mm diam. and these also distributed up

the dorsal side of the male zone to the spadix apex; male

zone subcylindric-ellipsoid, to c. 2 cm long, apically nar-

rowly acute and sterile, basally adnate to the spathe on the

dorsal side, sometimes with only the ventral-most stamens

(those exposed by gaping spathe limb) fertile, or more

extensively fertile, but always sterile on the dorsal side;

stamens crowded, truncate, dumbbell-shaped to irregularly

rectangular from above, often with the connective irregu-

larly broadened on one side, 0.9-1.2 mm across; thecae

each opening through a conspicuous, broad-rimmed pore.

Fruiting spathe more or less persistent in entirety; berry

depressed globular, 2-2.5 mm diam.; seed ellipsoid, 1.2-1.5

mm long, micropyle blunt, testa slightly ribbed.

Distribution. Malesia: West Borneo (known only from

and Bako National Park, Sarawak and Sanggau in W Kali-

mantan).

Habitat. Rheophytic near streams or waterfalls, 30-90

m asl. Elsener 184 reports that the habitat is lithophytic

under forest; in Sarawak the species is only known from

rheophytic ecology on hard sandstones in almost full sun.

Notes. The very glossy deep green leaf laminae are

striking; similarly lustrous leaves occur in rather few rheo-

phytic Schismatoglottideae, exceptions include Schisma-

toglottis roseospatha Bogner and Aridarum crassum S.Y.

Wong & P.C. Boyce.

Other specimens examined. SARAWAK: Kuching

Division, Bako National Park, Telok Tajor, mouth of Sg.

Tajor, Ashton S17945 (GH, K, L, SING); Bako National

Park, Telok Tajor, Purseglove P4944 (K, L, SING); Bako

National Park, Tajor waterfall, 01¢X43¡¦21.4"; 110¢X28¡¦15.1",

14 July 2007, P.C. Boyce & Wong Sin Yeng AR-2097

(SAR). KALIMANTAN: W Kalimantan, Sanggau, Elsener

184 (K, L).

Key to genera of Schismatoglottideae and

their principle subgeneric divisions in

Borneo

1a.

Wings of leaf sheath fully or almost completely

attached to the petiole; seeds never with a micropylar

appendage ............................................Schismatoglottis

1b.

Wings of leaf sheath extended into a ligular portion;

seeds various ............................................................... 2

2a.

Spathe not constricted; plants glabrous ....................... 3

2b.

Spathe constricted or if not constricted then plant vari-

ously to coarsely hairy (Schismatoglottis barbata; S.

pyrrhias) ...................................................................... 9

3a.

Thecae of anther never with horn- or needle-like pro-

jections ........................................................................ 4

3b.

Thecae of anther each with a horn- or needle-like

projection, although sometimes developing only after

female anthesis ............................................................ 6

4a.

Spadix almost completely adnate to spathe; male flow-

ers mostly sterile with a narrow zone of fertile flowers

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Botanical Studies, Vol. 49, 2008

Figure 3. Bakoa lucens (Bogner) P.C. Boyce & S.Y. Wong. A, Plants in habitat, Bako N.P.; B, Plant with inflorescence at the onset of

female anthesis. Note that spathe opening is facing downwards; C, Inflorescence at female anthesis. Note the spathe barely opens; D,

Inflorescence (spathe artificially removed). Note that the greater portion of the spadix is adnate to the spathe.

BOYCE and WONG ¡X Studies on Schismatoglottideae (Araceae) of Borneo

401

Figure 4. Bakoa lucens (Bogner) P.C. Boyce & S.Y. Wong. A & B, Spadix just prior to male anthesis. Note that the fertile male flow-

ers occupy only a small portion of the spadix, roughly adjacent to the opening of the spathe limb; C, Plant with inflorescence at late

anthesis (white with green acuminate tip; spadix brown) and at fruit mid-maturation (spathe green and thickened); D, Infructescence c.

half way through fruit dispersal. Note that spathe reflexed and torn away from the peduncle but is distally still convolute and clasps the

spent spadix.

402

Botanical Studies, Vol. 49, 2008

adjacent to spathe opening; peduncle declinate during

fruit maturation but twisting to become semi-erect at

fruit maturity; spathe persistent into fruiting, at fruit

maturity swiftly drying, reflexing and opening basally

by tearing at peduncle insertion to expose fruits but

remaining distally convolute and there clasping spadix.

Seeds with micropyle blunt ................................. Bakoa

4b.

Spadix entirely free or only part of the female flower

zone adnate to spathe; male flowers all fertile; pedun-

cle erect (and then spathe limb caducous) or declinate

(and spathe persistent) throughout fruit dispersal;

spathe limb either caducous early in anthesis or per-

sistent until fruit maturity and then falling still fresh to

reveal entire spadix and ripe fruits. Seeds with a pro-

nounced, hooked, micropylar appendage

......................

................................................................. Piptospatha 5

5a.

Spathe limb caducous early in anthesis (generally

between female and male anthesis); peduncle erect at

Figure 5. Bakoa lucens (Bogner) P.C. Boyce & S.Y. Wong. A, Dissected fruits showing ovules on a basal placenta. Note that blunt-

tipped micropyle; B, A single seed. Note that the dark, beak-like structure (uppermost) is the funicle. The micropyle is blunt. Phy-

matarum borneense M. Hotta; C, Ripe infructescence with one fruit opened and a single seed extracted to show the long, hooked,

micropylar appendage.

BOYCE and WONG ¡X Studies on Schismatoglottideae (Araceae) of Borneo

403

fruit dispersal; fruiting spathe a funnel-form splash-

cup .....................................Piptospatha elongata group

5b.

Spathe limb persistent; peduncle declinate at fruit dis-

persal; fruiting spathe caducous prior to fruit dispersal,

not forming a splash-cup ...............................................

....................................... Piptospatha grabowskii group

6a.

Thecae with needle-like projection extending only after

female anthesis; projection tipped with a weakly pel-

tate ovate-triangular flap. Spadix with distal pistillodes

..................................................................... Schottarum

6b.

Thecae with a horn- or needle-like projection present

prior to female anthesis; projection pointed and never

with a terminal flap. Appendix, where present, com-

prised of staminodes.................................................... 7

7a.

Sterile interstice of spadix with flattened scale-like

staminodes; anthers not excavated ...... Bucephalandra

7b.

Sterile interstice absent or with truncate staminodes;

anthers nearly always with the top excavated (but not

in A. incavatum) ......................................... Aridarum 8

8a.

Thecae on each end of the anther (seen from above). ...

.............................................. Aridarum Sect. Aridarum

8b.

Thecae together on one side of the anther (seen from

above).

............................. Aridarum Sect. Caulescentia

9a.

Thecae of anther without horn- or needle-like projec-

tions; ovules parietal; seeds without a micropylar ap-

pendage .......................................... Schismatoglottis 10

9b.

Thecae of anther each with horn- or needle-like projec-

tions; ovules basal; seeds with a long, hooked micro-

pylar appendage ....................................... Phymatarum

10a.

Stem pleionanthic

....................................................11

10b.

Stem hapaxanthic . .Schismatoglottis calyptrata group

11a.

Spathe limb mostly caducous ................................. 12

11b.

Spathe limb marcescent to crumbling and/or deliques-

cent ......................................................................... 13

12a.

Leaf sheath fully attached to petiole ...........................

............................... Schismatoglottis calyptrata group

12b.

Leaf sheath ligular

...................................................... .

............................... Schismatoglottis multiflora group

13a.

Petiole sheathing only at base; foliage leaves alternat-

ing with cataphylls .. Schismatoglottis tecturata group

13b.

Petiole usually sheathing for at least a third of its

length (rarely less); foliage leaves not alternating with

cataphylls.. .............................................................. 14

14a.

Spathe limb irregularly crumbling and breaking away

at or after male anthesis

...............................................

..................................Schismatoglottis asperata group

14b.

Spathe limb clasping the spadix and more or less

marcescent after anthesis, finally falling with spent

parts of spadix ......................................................... 15

15a.

Leaf sheath wings persistent; inflorescence nodding;

male and female zones of spadix more or less con-

tiguous ........................ Schismatoglottis corneri group

15b.

Leaf sheath wings usually (but not always) decidu-

ous; inflorescence more or less erect; male and fe-

male zones separated by a conspicuous partly naked

interstice .................. Schismatoglottis rupestris group

Acknowledgements. The collaboration and support of the

Sarawak Forestry Department, the Forest Research Centre

(Kuching), notably L.C.J. Julaihi & Lucy Chong, and the

Sarawak Biodiversity Centre, in particular Dr. Rita Ma-

nurang and Dr. Charlie Yeo is gratefully acknowledged.

Thanks are due to Datuk Amar (Dr.) Leonard Linggi Tun

Jugah, Graeme Brown & Dr. Timothy Hatch of Malesi -

ana Tropicals Sdn Bhd for their support and funding of

fieldwork in Sarawak. The second author is grateful for

the support provided by Faculty of Resource Science

and Technology, UNIMAS. This study is funded by the

Ministry of Higher Education, Malaysia by fundamental

research grant scheme No. FRGS/01(04)/609/2006(42)

under Sarawak Forestry Department Research Permit No.

NPW.907.4.2(I)-101 & Park Permit No. 58/20076

LITERATURE CITED

Bogner, J. and A. Hay. 2000. Schismatoglottideae in Malesia II ¡V

Aridarum, Bucephalandra, Phymatarum and Piptospatha.

Telopea 9(1): 183-194.

Hay, A. and Yuzammi. 2000. Schismatoglottideae in Malesia I ¡V

Schismatoglottis. Telopea 9(1): 1-178.

Mayo, S.J ., J. Bogner, and P.C. Boyce. 1997. The Genera of

Araceae. Royal Botanic Gardens, Kew, xi + 370 pp.

404

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