Arecaceae

By: Dhan R. Kandel

Taxon Description 

Unbranched trees, shrubs or prickly scramblers. Stems solitary or clustered. Leaves spiral, very large with basal sheath, petiolate, pinnate, palmate or costapalmate (palmate leaf with a short central axis), flagellum (sterile inflorescence modified as a climbing organ) present on leaf-sheath of some species of Calamus. Leaflets induplicate (V-shaped folding) or reduplicate (roof-shaped folding), acanthophylls (spine like basal leaflets) present in Phoenix, cirrus (a long whiplike organ extended from rachis) present in some species of Calamus. Inflorescence panicle or spike, peduncle with prophyll (the lowermost bract of inflorescence) and several spathes, only prophyll present in Phoenix. Flowers small, sessile, unisexual or bisexual, 3-merous, actinomorphic. Calyx 3-lobed, lobes fused at base. Corolla 3-lobed, lobes fused at base. Stamens often 3+3, filaments sometimes connate and/or adnate to corolla, anthers latrorse. Carpels 3, ovary superior. Fruit a fleshy or fibrous drupe, usually 1-seeded, 2- seeded in Wallichia.

Taxon Statistics

Worldwide 184 genera and 2,550 species (Mabberley 2017). 5 genera and 12 species in Nepal. Five species are known to be cultivated in Nepal, and they are included in the key but not described.

Plectocomia himalayana probably occurs in eastern Nepal (Henderson 2009), but I have not yet seen the specimen(s).

1 a Leaves palmate or costapalmate ……………………..…………………………………..……………………………..……………………………..………………………….. 2

   b Leaves pinnate ……………………………………………………..……………………………..……………………………..………………………………………………..………… 3

2 a Leaves palmate. Fruit grooved ………………………..…………………………………..……………………………..…………………………..……… 5. Trachycarpus

   b Leaves costapalmate. Fruit smooth ………………………………………………………………..……………………………..……………………………………..^* Sabal

3 a Acanthophylls present. Leaflets induplicate ………………………………………………..…………………..……………………………..………………. 4. Phoenix

   b Acanthophylls absent. Leaflets reduplicate ………………………………………………..……………………………..……………………………..…………………… 4

4 a Stems climbing, spiny. Cirri or flagella present. Fruit scaly ………………..……………………………..……………………………….…………… 1. Calamus

   b Stems erect, unarmed. Cirri and flagella absent. Fruit smooth …………………………………………..……………………………..………………………..…  5

5 a Leaflets with pointed apices ……………………………………..………………………………..……………………………..……………………………..…………. ^*Cocos

   b Leaflets, at least apical ones, with lobed or jagged apices ……..…………………………………..……………………………..………………………….……….. 6

6 a All leaflets with lobed or jagged margins. Inflorescence interfoliar …………………………………..……………………………..…………………………… 7

   b Only apical leaflets with lobed margins. Inflorescence infrafoliar ……………………………………..……………………………..……………….…………. 8

7 a Leaves unipinnate. Leaflets silvery grey beneath………………………..……………………………..……………………………..…………………  2. Wallichia

   b Leaves bipinnate. Leaflets green beneath …………………………………………………..……………………………..…………………..…………………^*Caryota

8 a Stems < 5 cm diameter. Inflorescence spicate. Fruit obovoid …………………………………..……………………………..……………………  3. Pinanga

   b Stems > 20 cm diameter. Inflorescence branched. Fruit ovoid .…………………………………..……………………………..…………….…………… ^*Areca