Erythropalaceae (Hassk.) Tiegh.

Genera Included:  Erythropalum Blume,  Heisteria Jacq., Maburea Maas.

Habit: Terrestrial, evergreen shrubs and trees (Maburea, Heisteria) and scandent shrub or liana (Erythropalum).

Parasitism: apparently autotrophic (data from Heisteria).

Roots: In parasitic members, forming haustorial connections to a number of different hosts.

Stem: Twig tomentum none or with simple hairs (Maburea).

Leaves: Developed, simple, alternate, distichous or spiral, petiolate, petiole with distal thickenings (Maburea and Erythropalum).  Primary venation pinnate (Heisteria) or palmate (in Maburea with five primary veins and in Erythropalum three primary veins). Petiole attachment slightly peltate in Erythropalum.  Secondary venation camptodromous and brochidodromous.  Tertiary venation plagiodromous and reticulate.  Quarternary venation (aerolation) meshes polygonal. Pubescence present or absent. 

Leaf anatomy: epidermal cells not lignified; guard cells lignified or not, narrow or wide, cuticular ledges of guard cells inconsipuous and thick,  paracytic, cyclocytic, and anisocytic stomata absent or present; schizogenous cavities in leaf absent;  laticiferous channels absent or present;  druses in epidermal cells absent or present; silicified walls of mesophyll and epidermal cells absent;  mesophyll sclereids absent or present; leaf cystoliths absent; petiole and median vein slerenchyma fibers and astroslereids present; node vascularization trilacunar (Heisteria); petiole base vascularization a complete vascular cylinder; distal petiole vascularization a complete vascular cylinder or a vascular cylinder with one or more adaxial or enclosed strands; median vein vascularization a simple bundle, a vascular cylinder with one or more adaxial or enclosed strands or a simple vascular cylinder.  

Wood anatomy: vessel solitary or grouped in multiples;  perforation plate type simple; vessel member length below and above 900 Ám;  intervascular pits (if present) alternate or opposite and scalariform; vascular tracheids assoc. w/ vessels absent; fibers as fiber tracheids or libriform fibers;  axillary parenchyma abundant, rare or absent;  axial parenchyma strand more than 7 cells wide;  rays heterocellular, of several rows of erect or square marginal cells; ray height above or below 1000 Ám;  wood cystoliths absent; silica bodies in ray cells absent. 

Inflorescence: In loose, slender, repeatedly dichotomous cymes in Erythropalum, axillary fascicles in Heisteria, and axillary, few-flowered fascicles or short spikes in Maburea.

Plant Sex: Flowers bisexual in Heisteria and Maburea, plants androdioecious in Erythropalum (Sleumer 1984).

Flowers: small (2-3 mm in length), pedicellate, glabrous or pubescent. Cauliflorous in some Heisteria.
Calyx: cup-shaped, with 5 lobes, partially fused at base.  Accrescent calyx absent or present (Heisteria).
Corolla: 4-5 lobed, slightly fused at base or not, lobes (petals) alternating with sepals, valvate, with or without hairs on interior surface.
Nectary: disk (between stamens and style) present in Erythropalum; disk connate to lower portion of ovary in Heisteria.
Androecium: 4-5 -merous, in one whorl (Erythropalum) or two; both whorls fertile (Maburea) or in some Heisteria the other as staminodes; filaments fused to base of corolla; anther basifixed, dehiscing by a slit.
Staminodia: present in Heisteria.
Pollen: Equiaxial, symmetry isopolar or heteropolar.  Mescolpium shape flat or convex.  Apocolpium shape convex.  Aperture number three to four, zonoaperturate.  Ectoaperture shape elongate (furrow).  Apertural membrane granular or vericose.  Endoaperture shape circular.  Relative size of the endo- and ectoaperture distinct.  Endoaperture granules none, endoaperture smooth and present, endoaperture smooth.  Exine in mesocolpium smooth or with a microperforate tectum and reticulate exine.  Granules and columella in infratectum absent or present. Foot layer surface smooth and irregular with masses.
Gynoecium: hypogynous (Maburea and Heisteria) to half-inferior (Erythropalum); mostly 1-locular above, showing 2-3 locular divisions below in Heisteria and Maburea; style short conical with slightly 3-lobed stigma.
Ovule: bitegmic or unitegmic, anatropous (Maburea).

Fruit: Drupes. Surrounded by accrescent calyx in Heisteria. Endocarp thin and woody in Maburea, enclosing a ribbed, pubescent seed. Endocarp in Erythropalum crustaceous, splitting from the top downward into 3-6 reflexed segments that are bright red on the interior (sometimes confused with an accrescent calyx). 

Seed: One per fruit, testa thin with copious endosperm containing both starch and fat (Heisteria).  Embryo: small at apex of endosperm. Indigo blue in Erythropalum, foul-smelling. 

Chromosomes: n=16 for Heisteria parvifolia.

Alternate Family Names: Heisteriaceae Van Tiegh.

Last updated: 14-May-18 / dln