Comandraceae Nickrent & Der

Genera included: Comandra Nutt. and Geocaulon Fern. 

Parasitism: Both genera are root hemiparasites: Comandra (Hedgecock 1915, Piehl 1965), Geocaulon (Moss 1926).

Roots: A description of a the roots of Comandra is given in Piehl (1965, pp. 7-8).  Haustorial anatomy and ultrastructure of the Comandra haustorium was reported in Toth and Kuijt (1976, 1977).  The anatomy of the Geocaulon haustorium is given in Warrington (1970).

Stem: consisting of erect aerial stems which arise from a branched rhizome.  

Leaves:  alternate, persistent, not dimorphic, developed (not squamate), exstipulate, sessile or on short petioles. Shape linear, lanceolate, oblanceolate, or elliptic with or without conspicuous venation.

Inflorescence: axillary and terminal in cymes (simple and compound dichasia) arranged in panicles, cymes or corymbs; peduncles subtended by foliaceous bracts; each flower subtended by a bracteole. Inflorescences (including flowers) glabrous. 

Plant Sex: Comandra has bisexual flowers whereas in Geocaulon they are unisexual (plants monoecious or andromonoecious).

Flowers: Pedicels absent or present; flowers radially symmetric, epigynous; rotate, top-, bell-, or funnel-shaped. Floral anatomy discussed in Smith and Smith (1943).

• Calyx: absent (completely fused to ovary, not leaving a calyculus).
• Corolla: petal number variable, even among flowers of the same inflorescence, (3-4-) 5 (-6-7), connate basally into a campanulate or urceolate floral tube (or tube absent); adaxial post-staminal trichomes present on petals of bisexual or male flowers.
• Nectary: present, epigynous, lobed.
• Androecium: stamens same number as petals, antepetalous, inserted at junction of petal and nectary disk; anthers dorsifixed, 4-locular, longitudinally dehiscent.
• Staminodia: present in female flowers of Geocaulon.
• Pollen: no reports available.
• Gynoecium: ovary inferior, unilocular throughout; style filiform or short conical; placentation free-central pendulous.
• Ovule: 2-4, unitegmic, from a twisted placental column.
• Embryo, etc.: embryology described in Ram (1957) and Bhatnagar (1991). Polygonum type embryo sac development with ephemeral antipodal cells. A lateral caecum originates from the embryo sac on the funicular side which grows through the ovule and enters the central placental column. Endosperm cellular.  Embryo lacking a suspensor. Ram (1957), based on embryological features, suggested removing Comandra from tribe Osyrideae and placing it in its own tribe, Comandreae.

Fruit: Fruit a dry nutlet or pseudodrupe with a stony endocarp, 3 cm or less in diameter.  Fruiting pedicel not thickened upwards.  Mature fruit crowned by persistent perianth parts (the "neck" in Comandra is the constriction below the persistent floral tube). In Comandra the exocarp is leathery, mesocarp hard and bony, and the endocarp absent (consumed by endosperm). In Geocaulon the drupe has a fleshy mesocarp.

Seed: single per fruit. Germination reported by Kuijt (1979).

Chromosomes: Chromosome numbers have been reported for Comandra umbellata as n = 14 (Piehl, 1965), n = 13 (Kondo & al., 1981); C. umbellata subsp. pallida n = 26 (Löve & Löve, 1982); and Geocaulon lividum (Löve & Löve, 1982) with n = 13. 

Alternate Family Names: none