Family Misodendraceae

Misodendraceae J.G. Agardh

Alternatively Myzodendraceae auctt.

Habit and leaf form. Chlorophyllous shrubs (or rather, shrublets). More or less ‘normal’ plants, or switch-plants. Leaves well developed (but small), or much reduced. Plants rootless (in the normal sense); partially parasitic. Parasitic on aerial parts of the host (of Nothofagus, the thickened haustoria promoting overgrowth of the host at the contact zone). Stem growth conspicuously sympodial (the apices of the stout twigs aborting at the end of each season). Leaves small; alternate; ‘herbaceous’, or leathery, or membranous; simple. Lamina entire. Leaves exstipulate.

Stem anatomy. Internal phloem absent. Secondary thickening developing from a conventional cambial ring, or anomalous (subgenus Angelopogon); (when anaomalous) via concentric cambia (via a secondary ring of bundles internally). ‘Included’ phloem absent. Xylem with fibre tracheids; without libriform fibres. Vessel end-walls simple. Primary medullary rays narrow (uniseriate). Wood storied, or partially storied (VPI).

Reproductive type, pollination. Plants dioecious. Female flowers with staminodes (three, situated in longitudinal furrows of the ovary and lengthening to form long, plumose bristles on the fruit). Gynoecium of male flowers absent.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes, or in spikes, or in catkins. Inflorescences catkinlike, compound racemes or spikes. Flowers bracteolate, or ebracteolate; very small, or minute.

Perianth sepaline, or vestigial (present, but much reduced, in female flowers), or absent (from male flowers); of female flowers, 3; 1 whorled. Calyx of female flowers 3; 1 whorled; gamosepalous (at the base); blunt-lobed (the three members adnate to the ovary except along their margins, but separate from each other save at the very base, and projecting beyond the ovary as three short, free lobes); open in bud.

Androecium of male flowers, 2–3. Androecial members free of one another (seated around a small, lobed nectary). Androecium exclusively of fertile stamens. Stamens 2–3. Anthers basifixed (terminal); dehiscing via short slits (the slit terminal, tangential); unilocular; bisporangiate. Pollen shed as single grains. Pollen grains aperturate; 4–12 aperturate; foraminate.

Gynoecium 3 carpelled. Carpels isomerous with the perianth. The pistil 1 celled. Gynoecium syncarpous; synstylovarious; partly inferior (by virtue of the adnate calyx). Ovary 1 locular. Epigynous disk present (annular). Gynoecium very shortly stylate. Styles 1; apical; shorter than the ovary. Stigmas 3. Placentation free central. Ovules not differentiated; in the single cavity 3; pendulous (from the top of the placental column); curved; without integuments; tenuinucellate. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Synergids pear-shaped. Endosperm formation cellular. Endosperm haustoria present; chalazal. Embryogeny complex and unusual, cf. some Olacaceae.

Fruit non-fleshy; indehiscent; three-angled or -winged, achene-like, or a nut (crowned by the accrescent, feathery, pappus-like staminodes). Dispersal by wind. Fruit 1 seeded. Seeds endospermic. Endosperm oily. Seeds without a testa. Embryo chlorophyllous (1/1); straight.

Seedling. Germination phanerocotylar.

Geography, cytology. Neotropical and Antarctic. Temperate. Southwest temperate South America.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Santaliflorae; Santalales. Cronquist’s Subclass Rosidae; Santalales. APG 3 core angiosperms; core eudicot; Superorder Santalanae; Order Santalales.

Species 11. Genera 1; only genus, Myzodendron.

Illustrations.
• Technical details: Misodendron.