Family Hypseocharitaceae

Hypseocharitaceae Weddell

~ Geraniaceae, rather than Oxalidaceae

Habit and leaf form. Stemless herbs. Perennial (with a thick taproot); with a basal aggregation of leaves. Leaves alternate; spiral; simple. Lamina dissected; pinnatifid. Leaves exstipulate.

Stem anatomy. Sieve-tube plastids S-type.

Reproductive type, pollination. Fertile flowers hermaphrodite. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes. The ultimate inflorescence unit cymose. Inflorescences radical, pedunculate or epedunculate 1–9-flowered cymes. Flowers regular; 5 merous; cyclic; polycyclic. Floral receptacle developing a gynophore (the gynoecium attached to a central column). Free hypanthium absent.

Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; polysepalous; regular; persistent; strongly imbricate. Corolla 5; 1 whorled; polypetalous; contorted.

Androecium 15. Androecial members free of the perianth; free of one another; 3 whorled. Androecium exclusively of fertile stamens. Stamens 15; triplostemonous; filantherous (the filaments subulate, persistent). Anthers dorsifixed; dehiscing via longitudinal slits; introrse. Pollen grains aperturate; 3 aperturate; colporate.

Gynoecium 5 carpelled. Carpels isomerous with the perianth. The pistil 5 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 5 locular (and five lobed); stipitate. Gynoecium stylate (the style filiform). Styles 1; apical. Stigmas 1; capitate. Placentation axile. Ovules 20–50 per locule (‘many’); biseriate; non-arillate; anatropous to campylotropous (becoming campylotropous after fertilization, via a bulge from the inner integument on the raphal side — cf. Geraniaceae); bitegmic; crassinucellate. Outer integument contributing to the micropyle. Hypostase present. Endosperm formation ab initio nuclear, or cellular (subsequently, commencing around the embryo).

Fruit non-fleshy; tardily dehiscent; a capsule. Capsules irregularly loculicidal (unlike the specialized structure of typical of Geraniaceae). Seeds scantily endospermic. Embryo well differentiated. Embryo coiled (‘cochlear’). Micropyle zigzag.

Geography, cytology. Neotropical. Andes.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rutiflorae; Geraniales (?). Cronquist’s Subclass Rosidae; Geraniales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; malvid; Order Geraniales (as a synonym of Geraniaceae).

Species 8. Genera 1; only genus, Hypseocharis.

Boesewinkel (1988) shows that the embyology and seed structure resemble Geraniaceae rather than Oxalidaceae or Linaceae.