J. M. Bompard
2.3 Taxonomy and Systematics
Taxonomic history
Subdivision of the genus
An historical review of the subdivisions of the genus Mangifera shows that two major groups have been rather consistently recognized in taxonomic treatments. Hooker (1862) was the fi rst to recognize two sections based on the characters of the fl ower disc: section I with a disc broader than the ovary, and section II with a disc stalk-like or wanting. These sections were later named by Marchand (1869) Amba, an Indian name for the common mango, and Limus, a Sundanese name for M. foetida in West Java, respectively. He also added a section Manga for M. leschenaultii, which in fact belongs to the section Limus.
In his monograph of the Anacardiaceae, Engler (1883) maintained Hook- er’s sections, and subdivided group A (Hooker’s section I) into two groups,
Taxonomy and Systematics 23
one group with four or fi ve petals and the other group with four petals. He considered the following sequence of morphological characters to be impor- tant for classifi cation: (i) texture of the leaves; (ii) number of fertile stamens;
(iii) prominence of veins; (iv) pilosity of infl orescences; and (v) leaf shape.
Pierre (1897) further divided the genus Mangifera into fi ve sections based on fl ower characters, i.e. number of stamens, the attachment of stamens to the disk, and the style. Two of these fi ve sections – namely section I Euan- therae, with a short thick fl ower disc and 4–12 fertile stamens, and section V Marchandora then consisting of M. camptosperma (currently considered a syn- onym of M. gedebe) are still maintained as they form clear-cut sections.
In his monograph, Mukherjee (1949) recognized two unnamed sections, conserving Hooker’s subdivision. Ding Hou (1978a) adopted the same method in his revision of the Malesian Anacardiaceae recognizing only Hooker’s two original sections and providing them with proper names and synonyms: section Mangifera (section I Hooker, section Amba Marchand, group A Engler, sections Euantherae and Marchandora Pierre) and section Limus (section II Hooker, sections Limus and Manga Marchand, group B Engler, and sections Eudiscus and Microdiscus Pierre).
Most recent classifi cation of the genus
The taxonomic classifi cation referred to herein follows that proposed by Kos- termans and Bompard (1993). This treatise includes the results of collections and surveys carried out between 1986 to 1998 in Borneo and peninsular Malaysia, which were initiated and sponsored by the International Institute for Genetic Resources (now Biodiversity International) and the World Wide Fund for Nature.1 It was published under the auspices of the International Board for Plant Genetic Resources (now International Plant Genetics Resources Institute) and the Linnean Society of London.
The most recent treatment of Mangifera refl ects the current status of what is still fragmentary knowledge. It can provide a basis for further studies involving all aspects of the wild relatives of mango, but particularly their potential in mango breeding. Determining phylogenetic affi nities based upon molecular markers could change our thinking about relationships among Mangifera species and among the cultivated forms of M. indica (see Interspe- cifi c Molecular Characterization section, this chapter).
The morphological characters used for identifi cation have been placed in the following sequence of importance:
Shape of the fl oral disc (see section Subdivision of the genus).
1.
Number of fertile stamens.
2.
Seed labyrinthine or not.
3.
Shape of secondary branches of the infl orescences: open or lax panicle, 4.
fl owers glomerulate or sub-glomerulate, the ramifi cations racemoid or spike like.
Pubescence of the infl orescence.
5.
Shape, number and attachment of the nerves (ridges or fi ngers) at the 6.
inner surface of the petals.
J.M. Bompard 24
Shape and size of the petals.
7.
Flowers tetra- or pentamerous (not a very constant character and often 8.
overlapping).
Reticulation of the leaves, especially of the lower surface.
9.
Shape of the leaf (only fully grown leaves of sterile branches can be used).
10.
Texture of the leaves.
11.
Deciduous or non-deciduous trees.
12.
Colour of the fl owers.
13.
Shape, colour and smoothness of the fruit.
14.
Number and size of the stone fi bres.
15.
Kostermans (Kostermans and Bompard, 1993) raised the sections to the rank of subgenus, i.e. subgenus Limus (Marchand) Kosterm., having a disc narrower than the base of the ovary, stalk-like or even lacking and subgenus Mangifera (Ding Hou) Kosterm., having a disc broader than the base of the ovary, cushion-like, often divided in four or fi ve lobes.
SUBGENUSLIMUS (MARCHAND) KOSTERM. Mangifera species of the subgenus Limus are quite distinctive and show only remote affi nity with the common mango.
This taxon is more primitive than the subgenus Mangifera and may be ances- tral to it, although the two subgenera may have originated from two different ancestors. The subgenus Limus consists of 11 species, which are native to the rainforests of western Malesia (peninsular Thailand, Malay Peninsula, Suma- tra, West Java and Borneo), with the exception of M. foetida, which extends to the east, possibly as far as New Guinea, and M. odorata which is only known in cultivation.
Kostermans divided the subgenus Limus into two sections: (i) section Deciduae for deciduous trees (i.e. M. caesia, M. kemanga, M. pajang, M. superba and possibly M. blommesteinii, M. decandra and M. lagenifera); and (ii) section Perennes for non-deciduous species (i.e. M. foetida, M. leschenaultii, M. macro- carpa and M. odorata) (Kostermans and Bompard, 1993). In deciduous trees, the bracts enclosing the buds leave a characteristic collar of dense, narrow scars, which persist on old twigs and are especially prominent in M. caesia and M. kemanga.
Mangifera lagenifera and M. decandra have ten stamens, fi ve of which are fertile. The other nine species have only one (and rarely two) fertile stamen(s) and two to four staminodes. The two species with fi ve fertile stamens (M.
decandraand M. lagenifera) and M. superba, M. caesia, M. kemanga and M. blom- mesteinii, whose leaves are apically aggregated into rosettes at the end of mas- sive twigs are particularly distinctive. The fruits of these species are broadly ellipsoid or pear shaped, not compressed, and have dirty whitish or pinkish mesocarp and lanceolate, and fi brous, non-ligneous leathery endocarp.
Mangifera subsessilifolia shows some affi nity with M. lagenifera and M.
blommesteinii; however, it has been placed among the species of uncertain taxonomic position due to a lack of complete study material. This is not a very rare species, but fl owering and fruiting seem to occur at intervals of, or
> 5 years, similar in this respect to M. lagenifera, which can be found growing
Taxonomy and Systematics 25
in old orchards in peninsular Malaysia. The fl owers and fruits of M. sub- sessilifolia are still unknown.
Mangifera foetida, M. odorata, M. caesia and M. kemanga are widely cultivated in the humid lowlands of the Malay Peninsula, Sumatra, Borneo, Java and Bali.
They have also been introduced elsewhere in South-east Asia; M. caesia, M. foe- tida and M. odorata are grown in the southern part of the Philippines, M. foetida is grown in Myanmar, and M. odorata is found in Indochina. They have been described in general reviews of tropical fruit (Ochse and Bakhuizen, 1931; Ochse et al., 1961; Molesworth, 1967; Verheij and Coronel, 1991).
Mangifera pajang, an endemic and commonly cultivated species in Bor- neo, is hardly known outside its native island. This deciduous tree has very stout twigs, with leaves more or less aggregate at the apices. The globose fruits, up to 20 cm in diameter, are the largest known fruits in the genus. The rough, potato-brown rind (0.5–1 cm thick) can be peeled off like that of a banana. Its bright, deep yellow, thick and fi brous fl esh is sweet with a dis- tinctive taste (Kostermans, 1965; Bompard, 1991a). In orchards in Borneo where M. foetida and M. pajang are both cultivated, forms with leaves and fruits having intermediate characters are occasionally found.
Mangifera caesia, M. foetida, M. pajang and especially M. odorata are impor- tant in tropical humid regions where the common mango cannot be grown satisfactorily. Mangifera pajang has potential as an ornamental tree, having brilliant rose-red blossoms (Philipps et al., 1982).
SUBGENUSMANGIFERA. The subgenus Mangifera contains most of the species (47), and is divided into four sections: (i) section Marchandora Pierre; (ii) section Euan- therae Pierre; (iii) section RawaKosterm.; and (iv) section Mangifera Ding Hou.
Section Marchandora Pierre. This section has only one species, M. gedebe Miquel (syn. M. camptosperma Pierre, M. inocarpoides Merr. and Perry, M. reba Pierre).
The labyrinthine seed is unique to this species, wherein the inner integu- ments penetrate the cotyledons and form numerous irregular folds. The fl at, discus-like fruit has only a very thin mesocarp. Mangifera gedebe grows in inundated places along rivers or lakes. The seed fl oats in water and is dis- persed during periods of high water, and this may explain its wide distribu- tion, from Myanmar through Malesia to New Guinea and the Bougainville Island.
Section Euantherae Pierre. The three species in this section (M. caloneura Kurz (syn. M. duperreana Pierre), M. cochinchinensis Engler and M. pentandra Hook.
f.) appear to be the most primitive among the species of the subgenus Mangifera. The fl owers are characterized by the presence of fi ve fertile sta- mens. The three species are mainly confi ned to Myanmar, Thailand, Indo- china and the north of the Malay Peninsula. The region is in the transition zone from the humid tropical rainforest to monsoon forest, and these species show an adaptation to low rainfall. Mangifera cochinchinensis, which occurs in south-eastern Thailand and in Vietnam, has small oblong fruits with a thin seed; the fruits are much relished by local people in southern Vietnam, although they are very acidic. Mangifera caloneura and M. pentandra are closely
J.M. Bompard 26
related, and can be mistaken for M. indica. However, their leaves are more leathery, have a more conspicuously dense reticulation, and the panicles are much more hirsute than the common mango. Mangifera caloneura occurs from Myanmar through Thailand to Indochina, in lowland evergreen forests, as well as in semi-deciduous forests. It is cultivated for its acidic-sweet fruit, and has been planted along the streets of Vientiane and Ho Chi Minh City (Saigon). Mangifera pentandra, apparently native to the northern Malay Pen- insula close to the Kra isthmus transition zone, is found in old orchards, in scattered locations, especially in Kedah and possibly also in peninsular Thai- land. It is also grown in the Anambas Islands and in Sabah, where it might have been introduced in early times. It is a prolifi c bearer, with small man- goes, c.8 cm length, and ripening green or yellow. The pale orange, watery pulp has a sweet taste and few fi bres.
Section Rawa Kosterm. This group, consisting of nine species, is not well delimitated. Most species have thick twigs and rather coriaceous leaves seated on protruding pedestals. The small, hardly fl attened ovoid or ellip- soid fruits that are black or partly red at maturity in several species are also characteristic. ‘Rawa’ is the Malay word for marsh, indicating that these spe- cies usually are found in periodically or permanently inundated areas. The fi ve species that occur in west Malesia (M. gracilipes, M. griffi thii, M. micro- phylla, M. paludosa and M. parvifolia) grow primarily in the swamps of south peninsular Malaysia, in central coastal areas of east Sumatra and western Borneo, and occasionally in peripheral uplands. It has also been reported from the Andaman Islands and from Thailand (Sreekumar et al., 1996; Eiad- thong et al., 2000a).
Mangifera andamanica and M. nicobarica are endemics from the Andaman and Nicobar Islands, respectively. Mangifera merrillii is a rare species endemic to the Philippines and M. minutifolia is known solely from a single collection from southern Vietnam. Mangifera griffi thii and M. microphylla are the only cultivated species within section Rawa. The former species is considered to be representative of the section, and is cultivated along the eastern coast of peninsular Malaysia and in western Borneo, and rarely in Sumatra. The fruits are small (3–5 cm long) and oblong or ovoid; the skin is rose-red, turning purplish black at maturity. The rind is thin and easily removed from the orange-yellow pulp, which is juicy and pleasantly sweet. Different forms are recognized by local people, according to the size and taste of fruits. Mangifera microphylla is a related, but less well-known species, having thinner leaves and a rather similar fruit.
Section Mangifera Ding Hou. With more than 30 species, section Mangifera is by far the largest. The common mango and the related M. laurina belong here. Species within the section have the same distribution range as the genus. The section may be divided into three groups based on fl oral structure and organ number variation: (i) those having pentamerous fl owers; (ii) those having tetramerous fl owers; and (iii) an intermediate group of species hav- ing both pentamerous and tetramerous fl owers. Within these three groups, it is possible to distinguish species with either puberulous or glabrous panicles.
Taxonomy and Systematics 27
Only characteristics of representative species within each group, especially those found in cultivation, are described below.
Pentamerous fl owers (14 species): Three species, M. laurina, M. minor and M. sylvatica, show affi nity with the common mango. Mangifera laurina is a species of the lowland forests of Malesia, where it is also under cultivation in old orchards. It can be distinguished from the common mango by having lax and widely pyramidal, glabrous or sparingly puberulous panicles. The fl ow- ers are smaller and are not glomerulate; the petals have a different shape, texture and colour. The fruit resemble those of a small common mango, with orange-yellow pulp, which is almost liquid at maturity. It is generally con- sumed when unripe. Several forms are in cultivation; however these are now becoming rare. Mangifera laurina is well suited to the humid tropical lowlands, fruiting well in areas where the common mango cannot be grown satisfacto- rily; moreover, it appears to be highly resistant to anthracnose (Bompard, 1991b).
Mangifera minor occurs east of Wallace’s line, from Sulawesi to New Guinea (east Malesia) and to the Carolines Islands in the east. It is adapted to a wide range of ecological conditions, growing equally well in dry savannahs and in tropical rainforests up to 1300 m. The fruit is obliquely oblong, 5–10 cm long, much narrowed, the tip obtuse, with a distinct beak and sinus. It is found in cultivation, although the yellowish fruit pulp is acidic and scant.
Mangifera sylvatica is found from Sikkim (up to 1200 m) to northern Myan- mar and Thailand, and apparently also in Yunnan up to 1900 m. The fruit is obliquely ovate, 8–10 cm long, much compressed distally forming a hook, has scanty whitish-yellow pulp which is almost fi breless. Other species are occasionally found in cultivation, for example M. rufocostata, which is esteemed by the Banjarese people of South Kalimantan for its very sour fruits that are used to prepare a spicy condiment with chilli.
Tetramerous fl owers (15 species): Mangifera altissima is apparently endemic to the Philippines, where it occurs mainly at low elevations in the forests from northern Luzon to Mindoro (Brown, 1950). The fruit is mango shaped, ovoid or ellipsoid, slightly compressed, up to 8 cm length, green or some- what yellow when ripe, with whitish, sweetish-acidic fl esh. It is commonly found in dooryards, and thrives in regions with distinct wet and dry seasons (Angeles, 1991).
Mangifera torquenda occurs wild in west Malesia, and is cultivated in south Sumatra and in Borneo, where it is common in the forests and orchards of eastern Kalimantan. The sub-globose fruit, c.7.5 cm long and 6.5 cm in diameter, is yellow-green with darker spots at maturity, and has a thin rind.
The pale yellow pulp has a rather pleasant sweet-acid, slightly resinous taste and a light turpentine smell. Short fi bres are attached to the seed. It is closely related to M. longipetiolata.
Mangifera magnifi ca is a common species in the rainforests of western Malesia, occasionally cultivated in central Sumatra and in West Kalimantan, where it has a special importance in the myths of Land Dayak peoples. The fruit is ovoid oblong, up to 12 cm long, 10 cm in diameter, only slightly compressed, greyish green with brown spots. The pulp is whitish, soft at
J.M. Bompard 28
maturity, sweetish acid. Sweeter forms are reported in central Kalimantan (J.J. Afriastini, personal communication). The stone is unique in the genus in that it lacks fi bres adhering to it.
Mangifera quadrifi da is found from peninsular Malaysia to the Moluccas.
The fruit is ellipsoid-globose, 6–8 cm long, green covered with black dots turn- ing completely black at maturity, and has a pale yellow, sweet-acid pulp.
Another form is recognized by its more coriaceous leaves, smaller fruits, c.4 cm long, having dark yellow pulp, purplish around the stone, and a sweet, palat- able taste, somewhat like prunes. Both forms are cultivated in old orchards.
Tetra- and pentamerous fl owers (four species, and also M. indica): Mangifera casturi is related to M. quadrifi da, from which it can be distinguished by leaf and fruit characters. It has never been collected in the wild, and is a favourite among the Banjarese people in south Kalimantan. The fruits are small, a little compressed and up to 6 cm in length, becoming completely black at matu- rity. The orange pulp is very sweet and palatable, and resembles ‘honey mango’ or ‘mangga madu’ grown in East Java. Although M. casturi bears heavily, it has a strong- to alternate-bearing habit. It is an excellent fruit for the humid tropical lowlands, and appears to be resistant to anthracnose. Sev- eral differently named forms exist; these have polyembryonic seeds. Mangifera rubropetala is also only known in cultivation, and may be a primitive race of M. indica.
SPECIES OF UNCERTAIN TAXONOMIC POSITION. There is a group of 11 disparate spe- cies of uncertain taxonomic position that cannot be placed with certainty due to the absence of adequate material. There are three species only known in China.