Eremospatha (G.Mann & H.Wendl.) H.Wendl., Palmiers : 244 (1878)

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Number of Taxa

  • 11 species

Discussion

  • The flowers of Eremospatha are remarkable for the thickness of the corolla tube and the small gaps between their short lobes; the androecial tube is also thick, fibrous, and extensively vascularised (Uhl and Moore 1973). The flowers are very like those of Plectocomiopsis, but this similarity is a parallel development. Although the dyad of two hermaphroditic flowers in Eremospatha is similar to that of Laccosperma, the two genera are otherwise rather different. Eremospatha is pleonanthic and has only minute rachilla bracts; Laccosperma is hapaxanthic and rachilla bracts are conspicuous. (J. Dransfield, N. Uhl, C. Asmussen, W.J. Baker, M. Harley and C. Lewis. 2008)
  • The leaves of this genus display a remarkable plasticity of form, from bifid juvenile leaves to regularly or irregularly pinnate adult leaves. Historically, this has caused much taxonomic confusion and a number of species have been described from juvenile material. (T.C.H Sunderland. 2012)

Biology And Ecology

Common Name

Etymology

Diagnosis

Description

  • Clustered (?always), spiny, high-climbing, pleonanthic, hermaphroditic rattan palms. Stem eventually becoming bare, with long internodes, usually circular in cross-section, sometimes obscurely 3-angled, juvenile stem apparently much more slender than the adult, sucker shoots apparently axillary. Leaves pinnate, bifid in juveniles, with a terminal cirrus; sheath strictly tubular, unarmed, longitudinally striate, sometimes with a thin caducous cover of indumentum; ocrea conspicuous, tightly sheathing, neatly truncate (?always); knee present in mature climbing stems, but rather inconspicuous; petiole present in juvenile stems, absent in mature climbing stems; rachis usually armed with reflexed spines, and sometimes bearing caducous indumentum; cirrus bearing neat pairs (rarely not paired) of reflexed acanthophylls, sometimes also with scattered reflexed spines; leaflets few to numerous, single-fold except, rarely, in juvenile leaves where lamina undivided, praemorse or abruptly narrowed to a pointed tip, or entire, linear to rhomboid, usually somewhat plicate, regularly arranged, variously indumentose, sometimes white tomentose beneath, usually armed along the thickened margins with conspicuous robust, distally pointing or reflexed spines, transverse veinlets moderately conspicuous; proximal few leaflets on each side of the rachis frequently very much smaller than the rest, strap-like, heavily armed along margins, and reflexed across the sheathed stem. Inflorescence arching outward, branched to 1 order, branches horizontal, peduncle enclosed within the leaf sheath and emerging from its mouth, flattened, not adnate to the internode, the surface usually minutely papillose; bracts throughout the inflorescence very inconspicuous; prophyll absent?; peduncular bracts absent; rachis much longer than the peduncle; rachis bracts low, triangular, striate, ± opposite or alternate, often united to form an incomplete sheathing collar; rachillae adnate to the inflorescence axis a short distance above the bract, either opposite (in which case subtended by a double bract) or alternate (in which case subtended by a single triangular bract), distal rachillae always alternate, distichous, rachillae minutely papillose, bearing ± distichous, minute, triangular, incomplete bracts, each subtending a pair of equal flowers without bracteoles. Flowers pale in colour, very fragrant; calyx thick, coriaceous, very shallowly 3-lobed distally, obscurely veined, minutely papillose; corolla very thick, coriaceous, divided at the apex to 1/4 to 1/3 its length into 3 short, triangular, valvate lobes, remaining approximate even at anthesis, the lobes then separating slightly; stamens 6, united into a massive, fleshy, epipetalous ring, ± occluding the mouth of the flower, clasping the gynoecium, free filaments angled, very short, anthers enclosed within the flower, ± medifixed, very short, somewhat sagittate, latrorse; gynoecium tricarpellate, triovulate, rounded, covered in reflexed scales, tipped by a columnar or tapered, ± 3-angled style, apically with 3 stigmatic angles, ovule basally attached, anatropous. Pollen ellipsoidal, bi-symmetric; aperture an extended distal sulcus; ectexine tectate, coarsely perforate, or rugulate-reticulate, aperture margin usually much finer; infratectum columellate; longest axis 32–63 µm [4/10]. Fruit 1–3 seeded, stigmatic remains minute, apical, perianth whorls persistent; epicarp covered in vertical rows of reddish-brown reflexed scales with fringed margins, mesocarp apparently fleshy at maturity, endocarp not differentiated. Seed subbasally attached, from the shape of 1/3 of a sphere to hemispherical or ellipsoidal depending on the number of seeds developing, sometimes slightly lobed or grooved, with a conspicuous abaxial ridge opposite the embryo, seed coat thin, scarcely fleshy, endosperm homogeneous; embryo lateral. Germination adjacent-ligular; eophyll bifid. Cytology not studied. (J. Dransfield, N. Uhl, C. Asmussen, W.J. Baker, M. Harley and C. Lewis. 2008)
  • Solitary or clustered, spiny, high-climbing, pleonanthic, hermaphroditic rattan palms. Stems circular to triangular in cross section, with short to long internodes, juvenile stems much more slender than the adult, sucker shoots axillary. Leaves pinnate, bifid in juveniles, becoming pinnate, with a terminal cirrus; sheath strictly tubular, unarmed, longitudinally striate, often sparsely to moderately covered with black or brown caducous indumentum or indumentum absent; ocrea conspicuous, entire, tightly sheathing, neatly or obliquely truncate or somewhat saddle-shaped, or drying and becoming longitudinally split; knee absent or conspicuous, vertically linear, abrupt or tapering at base, sometimes more linear, ridge-like; elaminate rachis present on lower stems, or absent; petiole present in juvenile stems, occasionally in mature climbing stems, armed with reflexed spines, sometimes with a caducous indumentum below, or indumentum absent; rachis armed as the petiole, with caducous indumentum below; cirrus armed as the petiole or unarmed; leaflets few to numerous, single-fold except, rarely, in juvenile leaves where lamina undivided, clustered or regularly arranged, linear-lanceolate, sub-orbicular to rhomboid, broadly attenuate at the base, narrowly to broadly praemorse or entire and apiculate at apex, concolorous or somewhat discolorous, usually armed along the margins with conspicuous robust reflexed spines; tranverse veinlets moderately to highly conspicuous; proximal few leaflets on each side of the rachis often smaller than the rest, shaped as the mature leaflets or somewhat linear, strap-like, sparsely to heavily armed along margins, laxly or tightly reflexed across the sheathed stem, or not reflexed and more regularly arranged; acanthophylls in neat pairs, opposite, rarely sub-opposite, parallel, or at varying angles to cirrus. Inflorescence arching outward, branched to 1-order, branches horizontal, peduncle enclosed within the leaf sheath and emerging from the mouth, flattened, not adnate to the internode, the surface glabrous or minutely to profusely papillose; bracts throughout the inflorescence inconspicuous or somewhat more conspicuous; prophyll absent although vestigial scar visible; peduncular bracts absent; rachis somewhat longer or than the peduncle; rachis bracts low, triangular, striate, opposite, alternate distally, sometimes united proximally to form an incomplete sheathing collar; rachillae distichous, opposite proximally and subtended by a double bract, becoming alternate distally, subtended by a single triangular bract, adnate to the inflorescence axis a short distance above the bract, bearing ± distichous, minute, triangular, incomplete bracts, each subtending a pair of equal flowers without bracteoles. Flowers very pale in colour, becoming darker post-anthesis, moderately to strongly fragrant; calyx thick, coriaceous, very shallowly 3-lobed distally, obscurely veined, minutely papillose, corolla very thick, coriaceous, divided at the apex to ¼ to 1/3 its length into 3 short, triangular valvate lobes, remaining approximate, even at anthesis, the lobes then separating slightly to reveal a discrete trilete opening; stamens 6, united into a fleshy epipetalous ring, clasping the gynoecium and occluding the mouth of the flower, free filaments angled, very short, anthers enclosed within the flower, ± medifixed, very short, somewhat sagittate, latrorse; pollen elliptic, monosulcate, the sulcus extended, exine foveolate, tectate; gynoecium tricarpellate, triovulate, rounded, covered in reflexed scales, tipped by a columnar or tapered, 3-angled style, apically with 3 stigmatic angles, ovule basally attached, anatropous. Fruit 1-3 seeded, stigmatic remains minute, apical, perianth whorls persistent; epicarp covered in vertical rows of reddish-brown reflexed scales with fringed margins, mesocarp fleshy at maturity, endocarp not differentiated, sarcotesta, when present, very thin. Seed sub-basally attached, from the shape of 1/3 of a sphere to hemispherical or ellipsoid (depending on the number of seeds developing), sometimes slightly lobed or grooved, with a conspicuous abaxial ridge opposite the embryo, seed coat thin, rarely fleshy, endosperm homogenous; embryo lateral. Germination adjacent-ligular; eophyll bifid. (T.C.H Sunderland. 2012)

Anatomy

Relationships

Fossil record

  • A single incomplete leaflet with a single spine near the acute, robust base (Eremospatha chilgaensis [Pan et al. 2006]) is described from the Oligocene Guang River flora of Chilga Woreda, Ethiopia. After comparison with morphologically similar leaf bases in subtribes Ancistrophyllinae and Raphiinae, the authors conclude that this fossil bears notable similarity to Eremospatha. (J. Dransfield, N. Uhl, C. Asmussen, W.J. Baker, M. Harley and C. Lewis. 2008)

Bibliography

  • Dransfield, J. , Uhl, N. , Asmussen, C. , Baker, W.J. , Harley, M. & Lewis, C. 2008. Genera Palmarum. The evolution and classification of palms. Kew Publishing, Royal Botanic Gardens Kew.
  • Sunderland, T.C.H2012. A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae).