Habit and leaf form. Herbs. More or less ‘normal’ plants (but achlorophyllous). Leaves much reduced. Plants succulent; totally parasitic. Parasitic on roots of the host (of shrubby Compositae, Clematis, Euphorbia, etc.). Leaves small; alternate; spiral; membranous (reduced to short scales); simple. Lamina entire. Leaves exstipulate.
Stem anatomy. Primary vascular tissue centrifugal. Cortical bundles present. Secondary thickening absent. Vessel end-walls simple.
Reproductive type, pollination. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in panicles, or in heads, or in spikes. Inflorescences dense compound spikes, thyrses or discoid heads; with involucral bracts, or without involucral bracts; pseudanthial, or not pseudanthial. Flowers bracteate; regular, or somewhat irregular; if irregular, slightly zygomorphic; 5–10 merous; cyclic; tetracyclic, or pentacyclic. Free hypanthium absent. Hypogynous disk absent.
Perianth with distinct calyx and corolla; 10–20; 2 whorled; more or less isomerous. Calyx 5–10; 1 whorled; gamosepalous (but only slightly so, at the most), or polysepalous (the sepals narrow). Calyx lobes markedly longer than the tube. Calyx unequal but not bilabiate to regular; persistent. Corolla 5–10; 1 whorled; gamopetalous; induplicate valvate, or imbricate; hypocrateriform, or tubular; persistent.
Androecium 5–10. Androecial members adnate; free of one another; 1–2 whorled. Androecium exclusively of fertile stamens. Stamens 5–10; inserted in the throat of the corolla tube (at the throat of the corolla, below its mouth); isomerous with the perianth; oppositisepalous; shortly filantherous. Anthers dehiscing via longitudinal slits; introrse; tetrasporangiate. Endothecium not developing fibrous thickenings. Anther epidermis persistent. Anther wall initially with one middle layer. Tapetum glandular. Pollen shed as single grains. Pollen grains aperturate; 3–4(–5) aperturate, or 6–8(–10) aperturate; colporate, or colpate and colporate (often with alternating aperturate and inaperturate colpi); 2-celled.
Gynoecium 6–14 carpelled. Carpels reduced in number relative to the perianth to increased in number relative to the perianth. The pistil 12–28 celled (each of the primary locules being divided into two locelli, by a median ‘false septum’). Gynoecium syncarpous; eu-syncarpous; superior. Ovary primarily 6–14 locular. Locules secondarily divided by ‘false septa’. Gynoecium stylate. Styles 1; apical. Stigmas 1 (capitate or lobed). Placentation axile. Ovules 2 per locule (primarily, i.e. with one per locellus); more or less horizontal; anatropous; unitegmic; tenuinucellate. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; persistent. Synergids pear-shaped. Endosperm formation cellular. Embryogeny caryophyllad.
Fruit fleshy, or non-fleshy; eventually dehiscent; a capsule (‘drupaceous’). Capsules irregularly circumscissile. Seeds copiously endospermic. Endosperm not oily (starchy). Seeds minute. Seeds with starch. Embryo rudimentary at the time of seed release. Embryo globose.
Physiology, biochemistry. Aluminium accumulation not found.
Geography, cytology. Neotropical. Temperate to sub-tropical. Southwest U.S.A., Mexico, Colombia. X = 9.
Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Solaniflorae; Boraginales, or Solanales (?). Cronquist’s Subclass Asteridae; Lamiales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; lamiid; Order unassigned to Order (as a synonym of Boraginaceae).
Species 5. Genera 3; Ammobroma, Lennoa, Pholisma.