Hyophorbes
Ian Edwards
This small genus of palms is teetering on the verge of extinction in its native habitat, the Mascarene Islands, in the Indian Ocean 800 Kilometres east of Madagascar, about same latitude as Rockhampton. The old name for some of the Hyophorbe species was Mascarena. Of the five species, three come from Mauritius and Round Island and one each from Rodriguez (also spelled Rodrigues) and Reunion Islands. Once they were forest palms, covering the mountains and valleys, but massive human overpopulation and the resultant land clearing of these little islands has reduced the palms to a few individuals. Because the Mascarenes are geologically young volcanic islands it has been suggested that the ancestors of the Hyophorbes arrived from somewhere else where they are now extinct, perhaps Madagascar, and later differentiated into the different species.
The name of the genus comes from the Greek, hys=pig and phorbe=food, the fruit having been used as pig-food. The genus belongs in the subfamily CEROXYLOIDEAE and the tribe HYOPHORBEAE, which means they are solitary unarmed pinnate palms. The other four members of the tribe are all from Central and South America – Chamaedorea, Synechanthus, Wendlandiella and Gaussia.
Two species, H. lagenicaulis and H. verschaffeltii, are renowned for having an attractively swollen trunk. All the species have a prominent crownshaft, below which are the inflorescences, which in bud are horn-shaped and erect. They all bear large fruit, which may take about a year to mature. They are monoecious, each plant having both male and female flowers in groups, so that in theory a single plant could produce fertile fruit. (Unfortunately this theory does not always work out.)
The last monograph to be written about the genus was back in 1978, by H.E. Moore Jnr.(Gentes Herbarium 11(4):212-245), but recent DNA studies have thrown more light on how the species are related to each other, as told on page 9.
Hyophorbe verschaffeitii The Spindle Palm
Native to the island of
Rodriguez. The common name comes from a tendency for the rather
stout
trunk to be narrowed above and below a swollen mid-section. However, it
clearly does not always do this, as a glance at different published
photographs shows a variety of swollen trunks. The crownshaft is smooth, a
dull green colour, about 80cm long, tapering towards the top. This species
has 5-10 leaves at maturity. The leaflets have a very promittent midrib
which in younger plants is coloured an attractive yellow.
The Spindle Palm is less cold-sensitive than the Bottle Palm, and grows well enough in Sydney (and Kiama) but quite slowly, less than two new leaves per year. There are several in the ROyal BOtanic Gardens, most as yet without a trunk; but in Bed 28b there is one, planted out in 1987, which has almost 2m of trunk. It is not easy to see, being visible only from the other side of the adjoining canal. When it gets to flower we should see a big inflorescence, to 85cm long, and intensly fragrant orange flowers.
Moore notes that the combination of bright orange flowers and a distinctive intense fragrance is not common among palms, but is shared with some species of the related genus Chamaedorea.Hybrids between H. verschaffeltii and H. lagenicaulis can be seen at Nong Nooch Gardens in Thailand. They appear to be more robust than their parents, the trunk being somewhere between a spindle and a bottle in shape, irregularly swollen, with a bulbous crownshaft and flower spikes which are thickened at the base and inwardly curved.
Hyophorbe indica
The one species from the island of Reunion. The name comes from the Latin, indica-from India, given in 1791 to the type specimen for the genus. Perhaps it refers to the island being in the Indian Ocean.
The palm is slender with
a trunk 13cm in diameter at the base. The crownshaft is up to 56cm
long. The petioles are long, 15-30cm (compared with the short petioles of
H. lagenicaulis and H. vershaffeitii). About five leaves with 48-50
leaflets each side when mature. The flowers are white and pleasantly
fragrant.
From all reports H. indica will be the best species for Sydney, being fast-growing and the most cold-hardy, while the coloured form is particularly attractive as a young palm.
As described by Moore, the palm is slender with a trunk 13cm in diameter at the base. The crownshaft is up to 56cm long. The petioles are long, 15-30cm (compared with the short petioles of H. lagenicaulis and H.verschaffeltii). About five leaves with 48-50 leaflets each side when mature. The flowers are white and pleasantly fragrant.
There is much confusion about the colour forms of this palm, largely resolved in the contibutions from Bill Beattie and Daryl O’Connor which follow, but with a few mysteries remaining. It seems clear that one form is green, the other is not, having been described by different people as black, purple, red, or orange. Moore in his monograph does not mention there being two forms. His description of the seedling appears to be of the green form. He describes the crownshaft as being smooth, green outside and violacious or lilac basally inside, sometimes yellowish above. The colour of the petiole he does not mention, and the leaflets are described as having a yellow-green midrib and one lateral vein each side, which are prominent and yellowish beneath. Also pale thin ramenta 5-9mm long on the midrib.
Don Hodel
(in THE PALM JOURNAL 127, March 1996) says Moore collected seeds on Re
union
in 1972 and distributed them through the Palm Society Seed Bank, with two trees
from those seeds being
at the Wilson Garden in Costa Rica; and those trees having since the early 1980s
supplied seed to collectors
around the world. In a previous PALM JOURNAL (No.123) Don Hodel has a good full
page colour photo of one of the Wilson Garden palms, clearly the green form,
with what looks to be about 4m of trunk, and a bunch of orange fruit.
In the same PALM JOURNAL (127) Phil Bergman says that seeds he received from Costa Rica and Hawaii produced bright green seedlings, whereas seeds from Reunion produced seedlings that were black-red in stem and petiole from the first leaf. There is a photo by Jeanne Price of the two forms of seedlings in a nursery in Reunion in PALMS & CYCADS No.63, June 1999, taken on the Price’s trip to the Mascarene Islands, with attached seeds. The red seedling has a darker coloured seed.
Some of those Sydney members who went on our trip to Cairns in August 1999 found Hyophorbe sp., about 50cm high, on sale at Limberlost Nursery. Some were green and labelled H.indica. Others looked almost identical except for their colour, which was a brownish purple on the petioles and leaf bases (but not the rachis which remained green), and these were labelled H.vaughanii, which we did not necessarily believe, but bought anyway.
Hyophorbe vaughanii
A native of Mauritius. It is easy enough to see why this species should be confused with H. indica, being another slender-trunked member of the genus, having a crownshaft that may have a yellowish tinge, and petioles described as orange-yellow-green.
Differences from H. indica are a shorter petiole (12-15cm), fewer and wider leaflets (35-38 each side) which have two lateral veins on each side of the prominent midrib (h. indica has one), the midrib carrying dark brown ramenta about 6mm long. The inflorescences are branched in three orders, those of H. indica to four. The flowers are orange rather than white and lack fragrance, unlike the fragrant flowers of H. indica.
There is no convincing evidence that this species has ever been in cultivation outside Mauritius.
Hyophorbe amaricaulis
From Mauritius. One lonely palm, possibly left when the original forest was cleared, surviving in the botanic garden at Curepipe, is all that is left of this species, unless a forgotten one turns up somewhere else, which is increasingly unlikely. Attempts to propagate from that palm have been attempted for decades, but the seeds have been infertile and attempts at tissue culture have so far been without success. The name comes from the Latin amarus=bitter and caulis=stem. (Apparently several of the species have a bitter tasting cabbage.) It differs from H. lagenicaulis and H verschaffeltii in that the trunk is of uniform thickness, not swollen, and from H. indica and H. vaughanii in having leaflets that have no space between them where they attach to the rachis.
Hyophorbe lagenicaulis The Bottle Palm
Well named, from the Latin, lagena=flagon, because of the greatly swollen trunk. This species may be an exception from the rest of the genus in not having been originally a forest palm, as today it grows only on exposed rock on Round Island, although it may also have once grown on Mauritius. It certainly likes full sun. The bottle trunk looks good until the palm gets old, when the trunk can become distorted. Young plants have 4-6 attractively arching leaves on a pinkish petiole, above a waxy green crownshaft. It is unlikely to be confused with any other palm. This palm is very slow growing, even in warm places like Florida. Unfortunately the Bottle Palm is just too sensitive to cold to last for long in Sydney. It came as a surprise then to find it growing so well 100Km south of Sydney in Colin Wilson’s garden in Kiama. The secret is a warm micro-climate where it has full sun but is protected from the winds – see the front cover photo.