鴨跖草屬

Commelina communis Credit: Jenn-Che Wang

Annual or perennial herbs. Roots fibrous. Stems branched, prostrate at base, erect above, rooting at nodes. Leaves sessile to subpetiolate, lanceolate or ovate; sheath cylindrical, pilose at margins. Prophyll sheathing, membranous, apex acuminate. Inflorescences terminal and leaf-opposed, composed of 1-2 cincinni enclosed in a spathe-like bract; spathe infundibuliform, or cordate and folded; bracteoles lacking; pedicels erect in anthesis and bent in fruiting. Flowers zygomorphic, usually dimorphic, in functionally male flowers pistil abortive; sepals 3, greenish, persistent, elliptic, concave, unequal, the anticous 2, elliptic, the posticous one lanceolate; petals 3, free, unequal: the lateral petals 2, blue to indigo rarely white, equal, planar, clawed, the limb broadly rounded-ovate; the medial petal white or blue, small; fertile stamens 3, anticous, dimorphic, the lateral stamens antesepalous, the medial stamen antepetalous; anther yellow, brown or blue, filaments glabrous; staminodes 2-3, posticous, all alike, antherodes cruciate; ovary ellipsoid-globoid, glabrous; Capsules brown, bilocular or trilocular, valves subequal, locules 1-2 seeded, dorsal locule uaually indehiscent. Seeds brown to black, deltoid or elliptic in outline, dorsiventral, ventral surface planar, dorsal convex, with farinose granules, embryotega lateral, hilum linear.

Species ca. 170, distributed throughout the tropical and subtropical world, Africa and Asia are the main centres; five species in Taiwan.

Lower Taxa

• Commelina auriculata Blume
• Commelina benghalensis Linnaeus
• Commelina communis Linn.
• Commelina diffusa Burman f.
• Commelina paludosa Bl.