Citation: Wight & Arn. ex Arn., Nova Acta Phys.-Med. Acad. Caes. Leop.-Carol. Nat. Cur. 18:355 (1836).

Derivation: Greek glossa, tongue; stigma, stigma; referring to the single broad stigmatic lobe characteristic of this genus and its allies.

Synonymy: Not Applicable

Common name: Mud-mats.

Description:
Small creeping ephemerals or ?short-lived perennials, rooting at the nodes; leaves opposite, sometimes clustered by suppression of internodes, entire, sometimes (G. elatinoides) obscurely gland-dotted.

Flowers small, solitary in leaf axils, sessile or pedicellate; bracteoles 0; sepals fused into a smooth tube with 4 or 3 short unequal lobes; corolla 2-lipped, the upper (adaxial) 2-lobed, the lower (abaxial) 3-lobed, rarely the lobes reduced to 4 or 3; stamens 4 in pairs of unequal length or 2, the anthers 1-celled; stigma with a single prominent broad flap covering the mouth and anthers, receptive above, when touched quickly bent back against the upper corolla lip.

Capsule thin-walled, dehiscing loculicidally into 2 valves; seeds many, reticulate.

Distribution:  4-6 species, all occurring in Australia; 3 of these extend to New Zealand, 1 also to India and Africa.

Biology: No text

Taxonomic notes: The relative conspicuousness of the mid-vein on the petiole and blade has been determined from spirit-preserved material.

Key to Species:

1. Calyx lobes 4; plants often hairy on leaves and the calyx; anthers 4	G. elatinoides 3.
1. Calyx lobes 3; plants glabrous; anthers 4 or 2
2. Pedicels 0-0.5 mm long with the fruits downturned into the mud, rarely erect and 5-9 mm long; corolla rudimentary, the flowers cleistogamous; anthers 2	G. sp. A 4.
2. Pedicels 2-70 mm long, always erect; corolla conspicuous; anthers 4-or 2
3. Anthers 2; leaves with the petiole 0.5-2 times the length of the blade, the blade almost as thin as the petiole, forward-directed with the mid-vein apparent below	G. diandrum 1.
3. Anthers 4; leaves with the petiole rarely 2, usually 3-5 times the length of the blade, the blade thickened, bent down and with the mid-vein obscure
4. Pedicels 3-10 rarely 20 mm long; corolla 2-lipped with the limb spreading, white, blue or pink; stamens included in the corolla	G. drummondii 2.
4. Pedicels 20-70 mm long; corolla more or less regular with the limb recurved, white; stamens exserted above the corolla	G. sp. B 5.

Author: Not yet available