Robust, solitary, unarmed, pleonanthic, monoecious, tree palm. Stem erect, to ca. 15 m tall, 28-30 cm diam. at breast height, graybrown, eventually becoming bare and closely ringed with leaf scars, internodes ca. 2.5 em. Leaves 30-36 in crown, pinnate, marcescent in juvenile palms, abscising neatly in adults; sheath tubular at first, to at least 82 cm long, with two lateral, ± entire, triangular lobes to 30 em long, 10 em wide at the base, tapering to ca. 8 em, the abaxial surface of the sheath covered with thick caducous gray-brown indumentum, the body of the sheath disintegrating into a mass of robust sinuous gray fibers ca. 3 mm wide, adaxially the sheath glabrous, reddish-brown; petiole very short, ca. 4-5 em long, to 8 x 2.3 em wide and deep, with scattered caducous scales; rachis to at least 4.4 m long, to 7 x 2.3 em wide and deep at the base, tapering gradually distally, adaxially ridged near the base, abaxially rounded, distally with 2 lateral grooves; leaflets ca. 120 on each side of the rachis, ± regularly arranged, very slender and crowded at the base, ± rigid or somewhat pendulous, ca. 47 x 1 em at the base of the leaf, ca. 112 x 4 em in mid leaf, ca. 65 x 1.8 em at the tip, ± acute, easily splitting and becoming bifid, adaxially glabrous, abaxially lacking powdery white wax, transverse veinlets short, conspicuos, minute punctiform scales present on longitudinal veins. Inflorescences solitary, infrafoliar, branching to 1 order; peduncle moderate, 8--13 em long, elliptic in cross-section, 4 x 1.7 em, with caducous gray-brown indumentum, ± glabrescent in infructescence; prophyll not seen, presumably inserted at the base of the peduncle and included within the leaf sheaths; peduncular bract inserted at the apex of the peduncle, woody, with solid beak, the whole to 90 em long, 3-5 mm thick, abaxially with conspiCUOUS longitudinal grooves, at anthesis the peduncular bract splitting longitudinally and circumscissile at the insertion, leaving a collarlike scar, the bract curling up on drying after abscission, adaxially the bract smooth, shiny, yellOWish green abaxially tomentose and longitudinally shallowly grooved; rachis very short, to 8--9 em long, to ca. 4 x 2 em diam., tapering to ca. 0.7 em at the tip, bearing ca. 30-50 crowded, spirally arranged rachillae, each subtended by a short, triangular, acuminate, coriaceous bract 1.1-7.5 x 1.0-2.8 em; rachillae glabrous and lacking white wax, yellOWish, becoming crimson in ripe fruit, straight, rigid, held at a narrow acute angle to the rachis, 45-66 em long, ca. 5-8 mm diam. at the base, tapering distally, each with a poorly defined swelling at the very base, proXimally with a bare portion 15-18 em long, distally bearing distichous triads in the proximal 13-19 em, paired staminate flowers in the middle 11-17 em and solitary staminate flowers in the distal 13-18 em, rachilla bracts triangular 1-4 x 1-6 mm; floral bracteoles well developed, broad, rounded, striate, rather coriaceous, shorter than the rachilla bracts. Staminate flowers narrow ellipsoid, ca. 13 x 4 mm; sepals to 2 x 2 mm, joined in the basal 1 mm, distally triangular, free and imbricate, glabrous, not striate; petals coriaceous, ca. 12 x 3 mm, tapering to a short acute tip, basally very briefly joined, abaxial surface glabrous, lacking white wax, obscurely striate; stamens 15, filaments 2 mm, anthers elongate 8 x I mm, erect, ± basifixed; pistiIJode absent. Pollen not studied. Pistillate flowers in bud, irregularly globose to obscurely angled, 9 x 6 mm, perianths persistent and enlarging in frUit; sepals broadly imbricate, 8-9 x 5-6 mm; petals 8 x 7 mm, broadly imbricate with short valvate tips; staminodal ring membranous, ca. 1 mm high; gynoecium ellipsoid, 6 x 4 mm, stigmas pyramidal in bud, 2 mm high. Fnlit I-seeded, oblate, 16 x 24 mm, with a short triangular beak to 3 mm long, 4 mm wide at the base, dark purplish-black at maturity, smooth, becoming striate when dry, surface glabrous except the beak where minutely and obscurely scaly; mesocarp thin, fleshy 1 mm thick, with longitudinal fibers, endocarp 15 x 22 mm, very thin, scarcely lignified, pores rather obscure, just below the equator. Seed oblate 13 x 20 mm, attached near the base with a broad hilum, with numerous anastomosing raphe branches, endosperm deeply ruminate; embryo lateral below the equator. Germination: adjacent-ligular; eophyll entire, lanceolate.
The existence of this population of Beccariophoenix on the western slopes of the High Plateau of Madagascar is quite astonishing. This new species grows in a completely different phytogeographic zone from the humid rain forest zone associated with B. madagascariensis. Manalazina belongs to the zone of the western slope of the Domaine Centrale defined by Humbert (1955). The primary vegetation is formed of sclerophyll forest with Uapaca hoieri and members of 5arcolaenaceae (Humbert & CoursDame 1965), but the current vegetation of the area consists mostly of a scrubby savannah. Furthermore, the climate is very different from that experienced by B. madagascariensis at Mantadia. In fact, B. alfredii experiences a subhumid temperate climate (Cornet 1974), drier than that of the east of Madagascar. The average temperature is 15-20˚C and the rainfall generally less than 1500 mm. The dry season is about five months long. The population of B. alfredii occurs at an average elevation of 1050 m above sea level; above that elevation, the palm becomes very rare, as the depressions between two mountains are too infrequent and where there are such depressions they are usually too dry. The soils in general in the region are ferralitic, but B. alfredii seems to grow solely on sandy soils on the banks of tributaries of the Mania River. Beccariophoenix alfred;; is the dominant species in the gallery forest and, reaching mostly 10-15 m, constitutes the only canopy species. The species grows so abundantly in the area that we estimated at least 500 mature individuals at this locality. In contrast, regenerating individuals are few. The dominance of this species may be due to the fallen leaves and inflorescences that carpet the ground, completely eliminating any other woody plants. Moreover, seed dispersal seems to be mostly by water. The flattened shape of the fruits allows them to be dispersed easily by water until they are deposited in a site favorable for germination. Sometimes seedlings are found actually growing in water but they mostly ocrur along the river bank. Perhaps this explains why the adult palms are restricted to a band along all the valleys.
At the moment, the only scientifically proven and recorded locality for B. alfredii is Manalazina. This population is limited to the west by the Mania River. Individuals become abruptly very rare as soon as one approaches the Mania, the river into which the tributary lined with Beccariophoenix flows. Fewer than twenty individuals of B. alfredii grow on the banks of the Mania, possibly because of its depth, which is unfavorable to the dispersal and establishment of seedlings. As we climbed up another mountain chain in the hope of finding other populations in further localities, we saw not one palm on the horizon. Because of the extremely difficult access and the time we had already taken to reach Manalazina, we were unable to conduct further searches for the palm. Meanwhile, we are optimistic concerning the existence of more populations further away in the region. Justin Moat, GIS specialist at the Royal Botanic Gardens, Kew, using satellite imagery, has looked for habitats similar to that at Manalazina. After analysing the very distinctive spectrum and relief seen in the satellite images at the exact coordinates of Manalazina, Justin was able to search for similar spectra and relief elsewhere in this part of the plateau. He found similar habitats but much further away from Manalazina. Other populations of B. alfred;i surely exist in the area - during our visit, we did not have the time to revisit Vilanitelo where the palms was first seen by Alfred's collectors, nor Marovato, the site of the large population mentioned by Alfred.
While we await the discovery of additional popuiations, we can declare that the population at Manalazina can be considered to be intact and not facing any major threat, thanks to mountain chains that effectively act as natural barriers protecting the population. This palm occurs in one of the most secure localities in the whole island. The area has one of the lowest densities of human population in the whole of Madagascar and this is, of course, very significant for the future survival of the species. Furthermore, no one locally seems interested in utilizing the palm at the moment, because it is Virtually impossible to transport the palm or its products up the 300 m of extremely steep slope from the valley bottom, and the locality is inaccessible to any of the usual forms of mechanized transport utilized in Madagascar. It is for these reasons that the locality is so deserted. During our four days camping we five from Antananarivo and our two guides saw no one apart from ourselves in the area.