The magnificent Nepenthes holdenii belongs to a closely related group of carnivorous Indochinese pitcher plants that are set apart from other pitcher plant species by their ability to flower without having first grown their pitchers (1). This species was first discovered in 2006 by botanist and photographer Jeremy Holden, and formally described in 2010 (4).
As in other pitcher plants, Nepenthes holdenii’s vase-shaped ‘pitchers’ are modified leaves that are deadly insect traps (5). The pitchers grow from tendrils projecting from a leathery leaf tip, and have a ‘lid’ and an opening at the top, the surrounding part of which is known as the peristome. Each year Nepenthes holdenii grows a circular arrangement of leaves at its base, from which climbing shoots grow to around five metres tall. Like other members of the Indochinese pitcher plants, Nepenthes holdenii develops swollen, irregular roots that are up to 25 centimetres thick (1).
The oval-shaped lower pitchers of Nepenthes holdenii grow near the ground and are red, brown or purple on the outer surface, with weak purple markings. Occasionally they are green with a red peristome, although this colouration is rare. The inside surface is creamy-white to yellowish green, and occasionally spotted purple. Two fringed ‘wings’, approximately 15 millimetres wide, run down the outer surface from the peristome to the bottom of the pitcher. The upper pitchers of Nepenthes holdenii are similar in shape but grow higher up on the plant and tend to become narrower towards the bottom. They are usually completely green, with or without a reddish-orange peristome, or may be brown, pink or red with faint purple spots and a reddish-orange peristome. The inside of an upper pitcher is creamy-white to yellowish-green and very occasionally spotted purple (1).
Nepenthes holdenii can be distinguished from all other closely related Indochinese pitcher plants by the unique growth of its inflorescence. Both the male and female flowers grow in small clusters, but on separate plants. Small stems grow from the main stem of the raceme, with each small stem dividing into two, bearing one flower on each branch (1).
- Lower pitcher height: 13 - 20 cm (1)
- Upper pitcher height: c. 25 cm (1)
- Lower pitcher width: 4 - 6 cm (1)
- Upper pitcher width: c. 6 cm (1)