I'm reading The God of Small Things, a novel by Keralan author Arundhati Roy. She masterfully plays with words, sometimes transforming them, mimicking the way a seven year old would (the main characters are seven in some parts of the novel). However, I'm stuck with this use of the words "Illimba", "mani" and "acuminus", all of them related to the field of plants. I'm not a native English speaker, so I thought they may make sense for someone who is. They may also belong to Malayalam vocabulary, but I couldn't find any information on that, despite all the studies performed on the novel.
The first word appears here:
‘Sophie Mol?’ she whispered to the rushing river. ‘We’re here! Here! Near the Illimba tree!’
The kids are on the riverside.
The other two words show up in a description of the jungle:
Beyond the swamp that smelled of still water, they walked past ancient trees cloaked in vines. Gigantic mani plants. Wild pepper. Cascading purple acuminus.
I just thought "mani plants" could be the species Epipremnum aureum, commonly known as "money plants", which grow in India. I also think "Illimba tree" can be the "bilimbi" or "bilimba tree", which grows in Kerala, where the story happens. However, I have no clue regarding "acuminus".