Aptandraceae Miers (1853)

Genera Included: Anacolosa (Blume) Blume, Aptandra Miers, Cathedra Miers, Chaunochiton Benth., Harmandia Baillon, Hondurodendron Ulloa, Nickrent, Whitefoord, and Kelly, Ongokea Pierre, and Phanerodiscus Cavaco.

Habit: Terrestrial trees and shrubs.

Parasitism: Positive evidence for parasitism (i.e. presence of functional haustoria) does not yet exist.  Taking into account the position of the family on molecular phylogenetic trees (see Malécot and Nickrent 2008), and assuming that parasitism has arisen once in Santalales and has since not been lost, it is expected that members of this family are root parasites. Reed (1955, p. 38) states that Aptandreae are root parasites, but no citation is given.

Roots: no data.

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

Leaves: Leaves simple, alternate, with developed blades and petioles, exstipulate.  Secondary venation brochidodromous, tertiary venation reticulate, quarternary venation (aerolation) of polygonal meshes.  Unicellular hairs present or absent.

Leaf anatomy: Leaf unicellular hairs absent or present.  Epidermal and guard cell lignification none or weak.  Guard cell lumina narrow and wide, cuticular ledges inconspicuous and thick.  Stomata paracytic. Schizogenous cavities in leaf absent.  Leaf laticiferous channels absent or present.  Druses in epidermal cells absent.  Silicified walls of mesophyll and epidermal cells absent or present.  Mesophyll sclereids absent or present.  Leaf cystoliths absent.  Petiole and median vein sclerenchyma fibers and astroslereids absent or present.   Vascularization of the nodes unilacunar.  Basal and distal petiole as well as median vein vascularization a simple bundle.

Wood anatomy: Vessel grouping solitary and grouped in multiples.  Perforation plate type scalariform.  Vessel member length over 900 um.  Intervascular pits alternate.  Vascular tracheids assoc. w/ vessels present.  Fiber tracheids and libriform fibers present.  Axillary parenchyma abundant, strand width less than 7 cells and more than 7 cells.  Rays with all cells procumbent (homogeneous) and heterocellular, one row of erect cells.  Ray height long, over 1000 um and short, below 1000 um.  Wood cystoliths absent.  Silica bodies in ray cells absent. 

Inflorescence: Various; axillary clusters or fascicles (Anacolosa, Cathedra, Phanerodiscus), panicles (Aptandra, Ongokea), and short, corymb-like panicles (Chaunochiton).

Plant Sex: Flowers bisexual or plants dioecious (Harmandia and Hondurodendron).

Flowers: Bisexual or unisexual, actinomorphic, dichlamydous, hypogynous, 4-5 (6, 8) - merous.

• Calyx: sepals developed, although the lobes may be small to very small, often cup-shaped. Accrescent in fruits of Aptandra, Chaunochiton, Harmandia, Ongokea, and Hondurodendron.
• Corolla: Apopetalous or sympetalous. The separate petals of Aptandra and Ongokea are long a strap-shaped. The corolla in Chaunochiton loranthoides is over 4 cm long, fused into a tube over half this length. In Harmandia the corolla is fused for most of their length. Petals with apical thickenings (uncinate), either with or without trichomes on inner surface.  In Cathedra and Phanerodiscus, the trichomes at the anther level differ from those more distal on the petal.
• Disk structures: A nectary disk may be absent or present.  When present, it may be extrastaminal (Aptandra, Harmandia and Ongokea) or between ovary and stamens (discal cupule), appearing at the same level as the insertion of the filaments (Phanerodiscus). A receptacular disk is seen in Cathedra that expands (accrescent) and eventually covers the surface of the fruit. In Phanerodiscus, the extradiscal and induvial cupules (not present at flowering) develop upon fruiting between the disk and the calyx, eventually expanding to form inflated festoons that surround the drupe.
• Androecium: 4-5 (6), filaments free or fused (Aptandra, Harmandia and Ongokea). Anther dehiscence valvate or porose, introrse or extrorse.  
• Staminodia: Present in Harmandia carpellate flowers (as is a pistillode).
• Pollen: Breviaxial in shape, symmetry isopolar and heteropolar.  Mescolpium shape flat or convex and concave.  Apocolpium shape convex and concave.  Aperture number three to four, zonoaperturate and six, diploporate.  Ectoaperture shape elongate (furrow) and round (porous, elliptic).  Apertural membrane smooth or scabrous and granular or vericose.  Endoaperture shape circular and 2.  Endo- and ectoaperture of distinct or identical size.  Endoaperture granules none,  smooth.  Exine in mesocolpium smooth or microperforate tectum.  Granules in infratectum absent or present.  Columella in infratectum absent or present.  Foot layer surface smooth and irregular with masses.  
• Gynoecium: Ovary superior; style very short to long, terminal cylindrical or conical; stigma lobed or unlobed. Ovary with one locule or a hint of being two-locular below. Placentation free central with pendulous ovules.
• Ovule: With one or no integument.
• Embryo, etc.

Fruit: A drupe or nut, enclosed in the accrescent calyx in Aptandra, Chaunochiton, Ongokea, Harmandia and Hondurodendron, the disk in Anacolosa and Cathedra, and by the festoons in Phanerodiscus. Lipids and starch either present or absent. 

Seed: With fleshy endosperm, tiny embryo positioned at one end. Commercially valuable seed oils are present in Ongokea. Seedling with epigeal germination in Ongokea.

Chromosomes: No chromosome numbers reported for the family.

Alternate (synonymous) family names: Cathedraceae van Tieghem, Chaunochitonaceae van Tieghem, Harmandiaceae van Tieghem.