Origin and Habitat: Borneo (Sabah)
Altitude: Up to about 400 m a.s.l.
Habitat: Areca rheophyticaSN|24951]]SN|24951]] is an undergrowth palm that, as the name states, is clearly a rheophyte plant (aquatic plant that lives in fast moving water currents, such as in a stream or river, in an environment where few other organisms can survive) that grows in river banks on ultrabasic rocks.
Remarks: Only a few palms have been described as rheophytes, among them Pinanga rivularis and Pinanga tenella from Borneo, Chamaedorea cataractarumSN|24307]]SN|24307]] from Mexico, Geonoma linearis from Colombia and Ecuador, Dypsis crinita and Ravenea musicalis both from Madagascar.

• Areca rheophytica J.Dransf.

Description: Areca rheophyticaSN|24951]]SN|24951]] is a small but most elegant solitary palm with arched feather like fronds.
Stems: Finger-like glabrous, pale brown up to 2 m tall and 1-1.5(-2) cm in diameter. With inconspicuous nodal scars about 3-5 mm hight, internodes 2-4 cm apart.
Crownshaft: 20-30 cm tall, 2-4 cm wide, enlarged and green.
Crown: With 7-8 leaves.
Leaves.. Up to to 60 cm long, petiole short about 8-15 cm long, pinnae (leaflets) 12-22 regularly arranged on each side of the rachis, single ribbed, very close, dark green. Sheaths usually less than 25 cm, smooth when fresh, drying
ridged.
Inflorescence: Erect usually less than 22 cm, The rachillae (flower-bearing branches) slender, very numerous,up to 120 mm long and 1 mm in diameter. Flowers grouped in one to several basal triad, otherwise bearing paired staminate flowers in a single row on one side. Staminate flower (male) creamy-white, lemon-scented; Pistillate flower (female) at anthesis about 11 x 3 mm tipped with 3 short stigmas.
Fruit: Narrow-ellipsoidal, approx 20 x 7 mm, pale green turning bright-red at maturity, mesocarp about 2-5 mm thick.
Seed: Spindle-like approx 15 x 5 mm.

Bibliography: Major references
1) J.Dransf. "Areca rheophytica", Kew Bull. 39(1) : 18-19 (1984)
2) Dennis Victor Johnson “Palms: An Action Plan for Their Conservation” IUCN, 1996. Page 4

Cultivation and Propagation: This is an excellent understory palm very highly sought after by palm collectors, but scarcely known in cultivation.
Soil: They prefers well draining, porous soils rich in humus. (but can even grow in soggy terrain).
Light: They do well in shade or half-sun spots, but keep their best deep green colour in full shade, if indoors place in a luminous position. Seedlings like a more sheltered area.
Watering: In cultivation they appreciates abundant waterings. During the summer or warmer months, water frequently to keep the soil from drying out.
Fertilization: Need a perfect fertilizer diet including all micro nutrients and trace elements or slow release fertilizer. Apply fertilizer 3 times a year, in spring, summer and fall...and if the palm is planted in full sun, fertilize more often. In a full sun location the fronds tend to turn lime-green or yellow, so the extra fertilization helps prevent this discolouration.
Hardiness: It can be difficult to get it to look its best without a great amount of heat and sun and so it is only really suited to the tropics in frost-free regions (USDA Zones 11-12)
Maintenance: These palms aren't considered self-cleaning but you'll only need to trim off an old frond occasionally.
Garden uses: It is rarely cultivated, but is an excellent understory palm if you can water it regularly. It is ideal where garden space is limited and a small plant is required. It can be grow indoors in a container for years before out growing the pot, but looks much better when planted in the ground and will thrive if given a spot in shade.
Propagation Method: Seed.