Diversity of Bamboos in north-eastern region of India with a note on their flowering occurrences from the area

Abstract

Bamboos (Poaceae), the ‘Green Gold’ of India are a wonderful gift of nature to mankind. These tree grasses contribute a significant component of tropical moist deciduous – evergreen forests and temperate – alpine forests of the country. Within India, the north-eastern region, comprising of eight states viz. Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura, is known as the most Bamboo rich zone. Remarkably, among ca 150 species occurring in India, the north-eastern region accounts for more than 60% of the total bamboo-wealth of the country out of which ca 40 taxa are endemic to the area. Dominant genera found are Bambusa, Dendrocalamus, Schizostachyum, Arundinaria, etc. which are represented in the region by more than 10 species each. On the other hand, genera like Ampelocalamus, Chimonobambusa, Stapletonia, etc. are represented in the region by single species each. It has been observed in the present study that arborescent genera like Bambusa, Dendrocalamus and Schizostachyum are common in low elevation tropical forests of the region whereas, reed bamboos like Arundinaria, Chimonobambusa, Yushania, etc. occurs in high elevation temperate and alpine forests. Flowering in bamboos is an interesting as well as curious phenomenon due to its semelparous and monocarpic nature. Flowering cycle recurs in bamboos at long intervals varying from 6 – 70 years or even upto 120 years. Usually the flowering bamboo clump dies after blooming. But, it was noticed in the present study that vigorous clumps are able to overcome the probability of death after flowering and only weaken considerably. In Bambusa cacharensis, it was noticed that diameter of the vegetative clump measures 23 – 26 cm whereas the same of bloomed clump measures 10 – 12 cm only (Devi & Bhattacharyya, 2013). Two types of flowering have been observed in the bamboos in North-eastern India viz. Gregarious and Sporadic. In this present study, flowering in several species viz. Bambusa cacharensis, B.tulda, Dendrocalamus longispathus, Melocalamus compactiflorus, Schizostachyum pergracile, etc. has been observed from different states of the region in recent times since 2011. Gregarious flowering in bamboos are considered as a dreadful event in several parts of north-eastern India as it results in population explosion of rodents which ultimately leads to devastating famine. This present study on bamboos of north-eastern India attempts to document the bamboo species of the region based on morpho-taxonomic analysis. As reproductive characters are rarely found, vegetative characters like culm sheath, auricle, etc. have also been taken into consideration for identification of the taxa.

Key words: Bamboo, Flowering, North-eastern India

Reference: Devi, M. and D. Bhattacharyya 2013. Flowering occurrences of Bambusa cacharensis in Barak Valley, Assam, India since its type collection: a note. Bamboo Science & Culture 26: 41–44. ISSN 0197– 3789.