Family Lacandoniaceae

Lacandoniaceae E. Martinez & C.H. Ramos

~ Triuridaceae

Habit and leaf form. Slender achlorophyllous, leafless herbs (with simple stems). Leaves absent. Plants with roots; saprophytic. Perennial; rhizomatous.

Stem anatomy. Secondary thickening presumably absent.

Reproductive type, pollination. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’. The ultimate inflorescence unit cymose (sympodial). Inflorescences terminal; lax, racemelike but sympodial, the flowers spiralled, the pedicels long and ascending. Flowers bracteate (the bracts small, trilobed); ebracteolate; small (4–5 mm in diameter); regular (but with very peculiar organization, the androecium inserted internally to the carpels); uniquely organized, with the stamens inserted internally to the gynoecium; more or less 3 merous; probably partially acyclic. Probably the gynoecium acyclic. Floral receptacle centrally depressed, with the carpels surrounding the stamens outside the depression. Perigone tube present (short).

Perianth of ‘tepals’; (4–)6 (the members acuminate to caudate tips); joined; without spots.

Androecium (2–)3(–4). Androecial members free of the perianth; all equal; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens (2–)3(–4) (inserted on the side of the receptacular depression, persistent); very shortly filantherous (the anthers about 0.3 mm long, the filaments about 0.1 mm). Anthers dorsifixed to basifixed (‘sub-basifixed’); dehiscing via longitudinal slits (the locules dehiscing by a single, common slit); introrse; bilocular; seemingly bisporangiate. Endothecium developing fibrous thickenings. The endothecial thickenings probably girdling. Anther epidermis persistent. Anther wall initially with one middle layer. Pollen grains nonaperturate (and intectate); verrucate; 3-celled.

Gynoecium (50–)60–80 carpelled. Carpels increased in number relative to the perianth. Gynoecium apocarpous; eu-apocarpous (the carpels densely papillose); superior. Carpel stylate; with a lateral style (the styles persistent); 1 ovuled. Placentation basal. Ovules anatropous; bitegmic. Outer integument not contributing to the micropyle. Endosperm formation nuclear.

Fruit non-fleshy; an aggregate. The fruiting carpel indehiscent; an achene. Seeds endospermic; ellipsoid with reticulate ornamentation, distally thickened, with a short basal projection. Embryo rudimentary at the time of seed release, or weakly differentiated.

Geography, cytology. Neotropical. Tropical. Mexico.

Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder supposedly Triuridiflorae; supposedly Triuridales (nearest to Triuridaceae, judging from attempting to ‘identify’ this description using INTKEY — assuming that the ‘flower’ is not a contracted inflorescence). APG 3 core angiosperms; Superorder Lilianae; non-commelinid Monocot; Order Pandanales (as a synonym of Triuridaceae).

Species 1. Genera 1; only genus, Lacandonia.

Data encoded from the original, deficient description and fairly unsatisfactory illustrations: Martinez and Ramos (1989), Máquez-Gusmán et al. (1989).