One feature of the thorelii-aggregate species group is their swollen, tuberous root stocks. I'll quote something written by Stewart McPherson (with his permission, Thanks Stew!) on the drought tolerant species of Thailand (for article in it's entirety see;
http://www.musekautas.lt/?p=5396 )
"Thailand is a country of great biological diversity, and a high proportion of the plant and animal species found in Thailand, differ from that found in Peninsula Malaysia and other parts of South East Asia. This is partly because, rainfall patterns in Thailand are strongly seasonalized, and a pronounced dry period is experienced for many months of the year. The severity and length of the dry period also varies geographically, but in northern Thailand, drought generally ensues from November until April, and during this time, many months may pass with little or virtually no rainfall. The dry season is so acute, that species of endemic plants have evolved adaptations in order to survive the ground. Uniquely, many of the endemic pitcher plants (Nepenthes) of this region have adaptations to store water and nutrients, such as swollen, tuberous roots and underground stems. Such adaptations enable many of the Thai Nepenthes to populate habitat that is very atypical for the genus, notably areas where the substrate dries out completely during the dry months."
Today I was transplanting some of our 15 month-old
N. suratensis seedlings for the gene banking program and thought to snap a few root pictures. Hopefully, others will contribute further to this thread adding other TA species. (I've seen a few posts by some of you in the past!)
Shawn
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