Revisiting Katou-Indel in 17th-century botanical treatise Hortus Malabaricus yields new finds for researchers

A palm originally described in the monumental 17th-century botanical treatise Hortus Malabaricus continues to fascinate botanists more than three centuries later, leading to the discovery of a new species and the reclassification of existing ones.

Recent studies on the palm, named Katou-Indel in the Hortus Malabaricus, Hendrik van Rheede’s work on the flora of the Malabar coast, have led researchers to conclude that the trees found in Kerala and Sri Lanka and elsewhere in India and neighbouring Bangladesh and Pakistan are two distinct species of the genus Phoenix.

A team from the Jawaharlal Nehru Tropical Botanic Garden and Research Institute (JNTBGRI) at Palode in Thiruvananthapuram and the Botanical Survey of India (BSI), Kolkata, has confirmed that van Rheede’s Katou-Indel is indeed Phoenix sylvestris, native to Kerala and Sri Lanka. In doing so, they have also reclassified three other Phoenix species as Phoenix sylvestris.

A major development is the identification of the palm found on India’s eastern coast and Bangladesh, Gujarat, Rajasthan and Pakistan as a new species. The researchers have named it Phoenix roxburghii after William Roxburgh, considered the father of Indian Botany.

Growing 12 to 16 metres tall, Phoenix roxburghii shares morphological similarities with Phoenix sylvestris, but differs by its taller solitary trunk, larger leaves and leaflets, musty-scented staminate flowers and larger, obovoid orange-yellow fruits, according to a paper on the findings titled ‘Revisiting Rheede’s ‘Katou-Indel’ and the discovery of a new species of Phoenix (family Arecaceae) from India,’ published in the scientific journal Phytotaxa.

What prompted the JNTBGRI and BSI researchers to take a closer look at Katou-Indel was an observation made by the 19th-century Botanist William Griffith that, “the fruits figured in Hortus Malabaricus (3: t 22–25) is very much smaller and of a different shape than it is in Bengal, at least in uninjured trees,” E.S. Santhosh Kumar of the JNTBGRI, one of the authors of the paper, told The Hindu.

Hendrik van Rheede, the Governor of Dutch Malabar, compiled the medicinal properties of the flora of Malabar coast in Hortus Malabaricus with the assistance of the physician Itty Achudan. The work in 12 volumes was translated into English by K.S. Manilal, who devoted 35 years to researching the work, more than three centuries later.

Over the years, Katou-Indel – a name which has its origins in Malayalam – has been subjected to many classifications. It was Roxburgh who coined ‘Phoenix sylvestris’ in the 19th century. In their paper, the JNTBGRI-BSI research team have confirmed it as such. They have also reclassified three different Phoenix species – P. pusilla, P.farinifera, and P. zeylanica – as the same as Phoenix sylvestris, a short palm that grows 3.5 metres to 5.5 metres tall.

The other authors include Joemon Jacob, N. Mohanan, K.C. Kariyappa and S. Suresh from the JNTBGRI and S.S. Hameed from the BSI.