Korthalsella Tiegh.

Scientific Description

Family Viscaceae.

Habit and leaf form. Small, chlorophyllous but parasitic shrubs. Switch-plants; with the principal photosynthesizing function transferred to stems. Leaves much reduced (to small scales). Plants rootless (in the normal sense — with haustoria); partially parasitic. On aerial parts of the host (of Acacia species). Young stems cylindrical, or oval in section, or flattened (forming cladodes). Stem internodes solid. Stem growth conspicuously sympodial, or not conspicuously sympodial. Mesophytic, or xerophytic. Leaves opposite (usually in two ranks); membranous; simple. Leaf blades entire; one-veined, or parallel-veined. Leaves without stipules. Leaf blade margins entire. Leaf anatomy. Hairs absent. Extra-floral nectaries absent.

Reproductive type, pollination. Fertile flowers functionally male and functionally female. Unisexual flowers present. Plants monoecious. Female flowers without staminodes. Male flowers without pistillodes. Anemophilous, or entomophilous.

Inflorescence and flower features. Flowers solitary (male), or aggregated in ‘inflorescences’; in fascicles (or clusters). The terminal inflorescence unit cymose. Inflorescences lateral; of about 20 flowers in 3–4 rows at every node, first formed flowers axillary and usually male, subsequent flowers formed laterally and usually in rows below the first, mostly female; floral cushion of multicellular branched hairs surround and separate clusters, white and inconspicuous becoming distinct protruding tufts in fruiting clusters. Flowers ebracteate; ebracteolate; minute to small; regular; cyclic. Perianth sepaline; 3; 1 -whorled; persistent. Calyx (if P so interpreted) 4; 1 -whorled; polysepalous, or gamosepalous; valvate; urceolate, or funnel-shaped, or in female flowers globular or pear-shaped and usually less than 0.5 mm in diameter, in male flowers globose to obconical, about 0.5 mm diameter and attenuate into a short stipe; regular; persistent. Calyx lobes triangular. Fertile stamens present, or absent (females). Androecial members definite in number. Androecium 3. Androecial members free of the perianth, or adnate (to the perianth); all equal; coherent (by the anthers); 1 -whorled. Androecium exclusively of fertile stamens. Stamens 3; all more or less similar in shape; isomerous with the perianth; opposite the perianth lobes; filantherous, or with sessile anthers. Anthers cohering (united into a synandrium); dehiscing via pores (apical); introrse; unilocular to many locular; bisporangiate, or tetrasporangiate. Fertile gynoecium present, or absent (males). Gynoecium 3 carpelled, or 4 carpelled. The pistil 1 celled. Carpels isomerous with the perianth, or reduced in number relative to the perianth. Gynoecium syncarpous; eu-syncarpous; inferior. Ovary unilocular; 1 locular. Gynoecium non-stylate. Styles 1; apical. Stigmas 1. Placentation basal (with a short placental column). Ovules not differentiated; in the single cavity 2; sessile; ascending; orthotropous.

Fruit and seed features. Fruit fleshy; indehiscent; a berry (with viscous tissue within); elastically dehiscent, or passively dehiscent; 1 seeded.

Etymology. After Pieter Willem Korthals (1807–92), Dutch botanist who travelled in the Dutch East Indies 1831–36.