Dypsis minuta Beentje is a miniature palm from the lowland rainforests of north-eastern Madagascar. A mature plant consists of a single stem barely 5 mm thick and at most about half a metre tall, densely covered in rust-red hairs and crowned by a few undivided, forked, greyish green leaves. The epithet refers to this tiny stature. Described only in 1995, it has a small natural range around the Bay of Antongil. Collectors of miniature palms grow it in pots and terrariums, and nurseries often advertise it as the smallest palm in the world, a title Dypsis tenuissima also claims.
Distribution and habitat
Kew records Dypsis minuta as native to Madagascar only, with no introduced range; Plants of the World Online places it in the north-east of the island. When it was described it was known from the Masoala Peninsula and the Maroantsetra district at the head of the Bay of Antongil. The specimens cited at that time came from Hiaraka and Antalavia on the west coast of Masoala and from the hills east of Sahavary village on the Andranofotsy River. Later collections add further sites on the western side of Masoala, around Ambanizana (the Amboninandzoka River) and Antalaviana near Mahalevona. Herbarium material gathered between 2010 and 2013 in the Vohibe forest near Vatomandry, far to the south, at about 600–660 m, has also been identified as this species; it would be a major southward extension of the range and has not been confirmed in the botanical literature.
It is a plant of lowland rainforest, growing in the understorey of primary hill forest and most often on ridge crests. Collection labels also record it on mid-slopes of hilly terrain on lateritic soils and in disturbed forest beside a river. The original account gives an altitude range of 200–550 m; the Masoala collections fall between about 200 and 550 m. The climate is hot and very wet all year.
Description
The account follows the original description in The Palms of Madagascar (Dransfield & Beentje 1995).
Habit and stem
- A tiny palm with one stem, 15–50 cm tall and up to 5 mm in diameter.
- Internodes roughly 1–2 cm long and thickly clothed in rust-red hairs; leaf scars only 0.2 mm wide.
Leaves
- Five to eight leaves in the crown. The blade is normally undivided; one collection (JD6371) was annotated as having several leaflets, but this was not visible on the specimen itself.
- Leaf sheath 6–9 cm long, open for half its length, densely covered with red hairs and bearing ear-like flaps (auricles) up to 1 cm long that are deeply fringed.
- Petiole 3–18 cm long and 1.5–2 mm thick, densely scaly.
- Blade undivided, 19.5–33 cm long and bright greyish green, with a midrib of 4.5–6 cm before it forks into two lobes of 16–26 × 1.3–2.5 cm. Each lobe has 4–6 main veins; tiny scattered reddish scales occur on both the major and minor veins, and the surface may carry white wax or fine white dots. The lobe tips are finely toothed and 2–4 mm wide.
Inflorescence
- Borne among the leaves, unbranched (a single spike; one specimen, JD6457, had a rachilla forked in two), held upright to spreading and curved rather than stiffly erect.
- Peduncle 6–19 cm long. Prophyll 7–15 cm long, pale brown, splitting only in its last 1 cm.
- The peduncular bract arises 6–11.5 cm above the base of the peduncle, is 3–12 cm long, smooth or with a few scales, and split along most of its length; a tiny open bract of 1.5–2 mm is often present above it.
- The single flowering axis (rachilla) is 4–12 cm long and 1–2 mm thick, finely downy or smooth, with widely spaced flower groups (triads).
Flowers
- Male flowers with fringed sepals 0.7–0.9 × 1–1.9 mm and petals 1.7–2 × 1.1–1.2 mm. Six stamens in a single whorl, on filaments 1–1.2 mm long; anthers 1.3–1.4 × 0.4 mm and versatile. Rudimentary pistil about 1 × 0.3 mm.
- Female flowers white, with fringed sepals 0.6–1.2 × 1–1.5 mm and petals 1.8–2.5 × 1.5–1.8 mm; staminodes 0.3–0.4 mm. The gynoecium measures 1.7–2.3 × 1.2–2 mm and sits on a short stalk of 0.2 mm.
Fruit and seed
- Young fruit slender, 11–12 × 2–3 mm. Ripe fruit and seed were not described in the original account.
Similar species
- Dypsis coriacea, which grows in the same forests, is the closest relative. Dypsis minuta is told apart by its hairy leaf sheath, its curved rather than erect inflorescence and its thinner leaves, which are not leathery, at least when fresh; it is also always single-stemmed and much smaller.
- Dypsis tenuissima, from Andohahela in the far south-east, is another candidate for the title of smallest palm and has even more slender stems.
Ecology
A shade plant of the forest floor in primary lowland and hill rainforest, chiefly on ridge tops. Flower buds have been collected in October, flowers and young fruit in February, and further material in January, March, April, July, September and November. In cultivation plants have flowered while only a few centimetres tall. Pollination and seed dispersal have not been studied.
Uses
The original account records no local names and no uses. Outside Madagascar it is grown as an ornamental by collectors of miniature palms.
Cultivation
A palm for warm, sheltered and constantly moist conditions. It is grown in pots, terrariums and indoor grow tents, and specialist nurseries describe it as suited to tropical or subtropical climates. It grows very slowly. Plants are cultivated in Hawaii (including outdoors at Hilo, where plants have been grown in the ground for about ten years and set seed), Puerto Rico, the Philippines, Florida and south-east Queensland, and in Sydney plants have flowered at about 3 cm tall.
Reports from growers give the following practical points:
- Germination can be very slow: one seed took 13 months to sprout.
- Moisture and humidity: the plant needs high humidity and a constantly moist root zone. A young plant in a narrow container dried out and died in Florida summer heat, while a companion moved into a larger pot that held more water recovered. Indoors, humidity of 40–55% appeared to be on the low side.
- Temperature: one grower in subtropical Australia keeps plants in a greenhouse where temperatures drop to about 2 °C without damage. In contrast, a grower in south-west Florida (zone 10a) repeatedly lost established plants within weeks and blamed the long, hot summers.
- Feeding: pot-grown plants show signs of nutrient deficiency without regular, balanced fertiliser.
Conservation
Conservation status: Vulnerable.
When it was described the species was known from a small area with no formal protection, and its numbers were believed to be quite low. Most of its known sites are now within Masoala National Park and nearby protected forest, but the overall range remains very small.
Name history
- Original publication: Dypsis minuta Beentje, in J.Dransfield & H.Beentje, The Palms of Madagascar: 313 (1995). No synonyms are recorded.
- Type: Madagascar, Maroantsetra, Andranofotsy River, Sahavary, hills east of the village, ridge top in primary forest, 300 m, 11 February 1988 (flowers and young fruit), Dransfield, Henderson & Staniforth JD6457 (holotype K; isotypes P, TAN).
- Other collections cited in 1995: Dransfield et al. JD6371 (Hiaraka, October 1986, in bud); Dransfield et al. JD6483 (Antalavia, February 1988, young fruit, the source of the published fruiting detail); and Lyall 323 (no locality, gathered before 1867), one of the original syntypes of Neophloga heterophylla but a different species from that name's lectotype, Baron 486, which belongs to Dypsis heterophylla.
- Latin diagnosis: the species was separated from Dypsis coriacea by its hairy leaf sheath, arching inflorescence and leaf that is not leathery in life.
- Etymology: Latin minutus, "very small", chosen because it is among the smallest palms of Madagascar.
- Pronunciation: DIP-sis mih-NOOT-ah.
- Classification: subfamily Arecoideae, tribe Areceae, subtribe Dypsidinae. Kew keeps it in Dypsis, the genus that Eiserhardt et al. (2022) narrowed by moving many species to Chrysalidocarpus, Vonitra and other genera.
