Wild bananas around Chiang Mai

In two recent blogs I treated the commonly cultivated banana clones ‘Gluay hom thong’ (=’Gros Michel’), ‘Gluay hom kiao’ (a Cavendish banana), ‘Gluay nam wa’ (=’Ducasse’) and ‘Gluay hak muk’ (=’Silver Bluggoe’). These are all mutants with chromosome doubling making the fruits bigger, and with female sterility making them seedless. These clones or cultivars would die out without the cultivation by humans. There are hundreds of banana cultivars, and many more names because one clone may have one or several different names in each country.

What about the many tall and slim wild forest bananas you see along winding mountain roads in the Chiang Mai province here in northern Thailand? The locals usually give them the collective name ‘Gluay pa’ meaning ‘forest banana’, i.e. fertile bananas with small fruits packed with hard seeds. Although not at all as delicious as the refined selected cultivars we normally grow, biting into a forest banana helps you understand Stone Age man’s conditions and the ancestors of our superb cultivars. It is possible that Stone Age man used the seedy wild bananas for cooking only. Before we try to sort out what the local forest bananas are, let’s first look at the banana family globally.

According to Mabberley’s plant book (2008) there are three genera in the banana family Musaceae, comprising 44 species in the world. Of these, the yellow-‘flowered’ genus Musella with only one species occurs in the Chinese drylands, and the genus Ensete, which has no edible bananas and does not make suckers, is composed of six species. Although Smitinand (2001) lists Ensete glaucum and E. superbum as native to northern Thailand, they are not recorded from Doi Suthep mountain outside Chiang Mai. I have seen Ensete in Opkhan national park near Dokmai Garden, and I collected seeds from that specimen. Since I have not seen it in the actual jungle, only near the temple and the checkpoint, and since locals say a monk brought it, I figure this is an exotic ornamental. We grow the African Ensete ventricosum at Dokmai Garden.

If we exclude the genera Musella and Ensete, then there are only 37 wild true banana species (genus Musa) in the world. Although this seems like a very small plant group compared with the orchid genus Dendrobium with 1250 species worldwide, banana systematics is quite complicated and  it is likely the coming few years will expand our knowledge. The true bananas (Musa) are native to Japan, China, Southeast Asia, Indonesia, Australia and the Pacific islands. The two ancestors of our food bananas, ‘Noble banana’ (Musa acuminata) and ‘Humble banana’ (Musa balbisiana), are native to the rain forests and jungles of Southeast Asia including Thailand. They are not native to Africa nor South America.

According to Smitinand (2001) there are only eight indigenous Thai banana species (Musa spp) if we omit the exotics and the cultivated bananas. I include M. balbisiana as a native although Smitinand considers it exotic. If we consider Maxwell and Elliott (Vegetation and vascular flora of Doi Suthep-Pui national park, northern Thailand, 2001) there are only four species of wild bananas on Doi Pui-Doi Suthep mountain in Chiang Mai: M. acuminata, M. balbisiana, M. itinerans and M. sikkimensis (this last species is not listed by Smitinand 2001). The authors discuss that M. balbisiana might be a relict from cultivation. Although being full of seeds many M. balbisiana varieties have been cultivated as fodder, such as Musa balbisiana ‘Gluay tani dam’ (=’Thai black’). This variety is a superb ornamental growing here at Dokmai Garden.

Here is an attempt to a simplified key to these four species when mature:

1. Leaf sheath pruinose (waxy)…………………………………………………………………2

1. Leaf sheath not pruinose (not waxy)………………………………………………………4

2. Flower stalk glabrous………………………Musa balbisiana (Humble banana)

2. Flower stalk hairy………………………………………………………………………………..3

3. Bracts rounded at apex…………………….Musa balbisiana (Humble banana)

3. Bracts acute at apex……………………………Musa acuminata (Noble banana)

4. Pseudostems without red colours…………Musa acuminata (Noble banana)

4. Pseudostems with red or purple colours…………………………………………………5

5. Pseudostems dark purple……………………..Musa itinerans (Stream banana)

5. Pseudostems with reddish tinge…..Musa sikkimensis (Darjeeling banana)

You can read more about three of the four species in Flora of China.

Musa itinerans is a dominating banana species in the evergreen valley of Mae Kanin Tai inside the Opkhan national park, just south of Chiang Mai (400 m above sea level). Its pseudostems are almost black with many dead leaves, growing to at least three times the size of a tall man. It seems restricted to the banks of meandering streams.

The scientific name for the banana genus, Musa, was coined by the Swedish biologist Linnaeus. It is a Latinized form of ‘Mauz’, the Arab word for banana used in Avicenna’s (Ibn Sina) encyclopedia of medicine from the year 1025 (‘Canon Medicinae’ in its Latin translation). The Arabs believe a banana was the forbidden tree (‘of knowledge’ according to Christianity) in Paradise, and so Linnaeus coined the scientific names Musa paradisiaca and Musa sapientum (‘sapientum’=wise) for what he believed were two different banana species. These names are no longer used because they referred to hybrids (a mix of species).

Wild bananas are full of seeds so that they can reproduce.

Text & Photo: Eric Danell

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