Commelinaceae Mirb.

By: Jyoti P. Gajurel, Krishna K. Shrestha & Robert B. Faden

Taxon Description 

Annual or perennial herbs. Roots fibrous to modified into tubers. Rhizomes present or absent. Stems erect to procumbent. Leaves petiolate or sessile, alternate, distichous or spirally arranged; sheaths open or closed, nodes swollen, blade simple and entire. Inflorescence a panicle or coiled cyme, penetrating the leaf sheath, rarely flowers solitary and terminal. Flowers bisexual, rarely unisexual, actinomorphic or zygomorphic, bracts spathe-like. Sepals 3, free or connate at base, boat shaped, membranous. Petals 3, blue or white or pink, longer, one clawed, free, sometimes connate and tubular. Stamens 3–6, basifixed, filaments hairy, free, staminodes 0–3, filaments glabrous or torulose-villous; anthers parallel or slightly divergent. Ovary 2- or 3-loculed; ovules 1 to several per locule; Capsules 2- or 3-valved, rarely indehiscent. Seeds 1–7 per valve, cylindric, ellipsoid or reticulate, hilum linear or orbicular.

Taxon Statistics

The family comprises 41 genera and 731 species, mostly tropical and subtropical with considerable diversity extending into northern temperate regions. Nine genera and 24 species in Nepal.

Key to Genera

1a Procumbent herb. Inflorescences penetrating leaf sheath …………………………………………………………………………………………………………………………………….. 1. Amischotolype

b Erect, climbing or prostrate herb. Inflorescences emerging through the mouth of leaf sheath …………………………………..………………………..…………………………..……………..… 2

2 a Climbing herb. ……………………………………..………………………………………………………………..…………………………..…………………………..………………….………………….……. 2. Streptolirion

b Erect or prostrate herb. ………………………………………………………………………………………..…………………………..…………………………..…………………….……………………….…………….…..…. 3

3 a Inflorescences terminal. Fruit baccate ………..………………………………………………………….…………………..…………………………..…………………………..………….………………………. 3. Pollia

b Inflorescences broom like or axillary. Fruit capsular .………………………………………………………………………………..…………………………..…………………………..……….…..……..…………… 4

4a Inflorescence a dense, terminal thyrse. Seeds hemispheric …………………………………………..…………………………..………………………..….…………………………………….…… 4. Floscopa

b Inflorescence lax, axillary or terminal. Seeds angular ………………………………………………..…………………………..……………………….…..………….………………………….…..…………………… 5

5a Petals fused into a tube. Fertile stamens 6 ……………………………………………………………………………..…………………………..………….………………..……………….…….……..…… 5. Cyanotis

b Petals free. Fertile stamens 3, rarely 6 .……..……………………………………………………………..…………………………..…………………………..…………….…………………..……..…….…..…..…..……… 6

6 a  Involucral bracts present and spathe like ………….……….…………………………………………..…………………………..…………………………..………………………………………………….……………… 7

b Involucral bracts absent, rarely present and then spreading ……………………………………………………………………………………………………………………………………………………….……… 8

7a Flowers actinomorphic. Capsule 3-valved …………………………………………………………………………..……………………………..…………………………..…………………..……..… 6. Tradescantia

b Flowers zygomorphic. Capsule 2-valved …….…………………………………………………………………………………………………………………………………………….……….…………… 7. Commelina

8a  Antherodes sagittate and 3-lobed ………………………………………………..…………………………..…………………………..…..…………………………………….…………….……..……….. 8. Murdannia

b Antherodes dumbbell-shaped and 2-lobed ….…………………………………………..…………………………..………………………….…………………………………………………..…… 9. Rhopalephora

Uncertain Taxa

The species which are reported to occur in Nepal (Hara et al., 1978, Press et al., 2000, Rajbhandari & Rai, 2017, Shrestha et al., 2022, etc.), but the specimens are either not available in the national and international Herbaria, or poor specimens without reproductive parts, are placed in the Uncertain taxa category. It is suggested to collect some specimens of such species, and needs further study to confirm its occurrence in Nepal.

 Murdannia vaginata (L.) G.Bruckn., Engler, Nat. Pflanzenfam., ed. 2. 15a: 173 (1930).

Commelina vaginata L., Mant. Pl. 2: 177 (1771), Dictyospermum vaginatum (L.) D.Y.Hong

Distribution: Nepal, E. Himalaya, Assam-Burma, S. Asia, E. Asia, SE Asia, and Australia.

Altitudinal range: 100–200 m.

Ecology: Marshes and moist sandy places.

Flowering: December–January. Fruiting: January –Feburary.

The specimen(s) of this species are not deposited in the herbaria of Nepal and elsewhere. However, Siwakoti and Verma, D.M. (1995) mentioned this species from Nepal (Press et al., 2000). It needs further study.

2. Pollia hasskarlii R.S. Rao, Notes Roy. Bot. Gard. Edinburgh 25(2): 188 (1964).

Pollia aclisia Hassk.

Distribution: Nepal, E Himalaya, Tibetan Plateau, Assam-Burma, S Asia, E Asia, and SE Asia.

Altitudinal range: Not known.

Ecology: Moist ravines, in shade.

Flowering: March–June. Fruiting: July–August.

Note: A doubtful species Pollia hasskarlii occurs in Nepal (www.powo.org), but there is no herbarium specimen deposited in the herbaria of Nepal as well. It needs further study.