Adiantum reniforme

The species name reniforme suggests a kidney in outline.  This is a very unusual Adiantum.  It is found at 3 very separated locations. In Canary Islands, around the Three Gorges area in China and parts of Africa, Kenya, Tanzania to the islands off Africa like Madagascar and Reunion islands.  This points to an ancient lineage now widely separated deal to unsuitable habitat or effects of geological past.  Canary Islands flora evolved from extension of East African flora separated by the Sahara desert.  Its very isolated existence in China is particularly interesting. Surely, there must be a few suitable habitat between China and Africa that's comfortable enough for a fern during ice age.  

From a hobbyist perspective, it is a very small and compact growing fern.  The scaly, crispy or perhaps more aptly brittle texture of mature frond is distinctive. The fronds rattle like a windchime of thin seashells on a string. Its texture reminds me of Equisetum. Its internals filled with silica. I purchased this fern from a rooftop nursery at Ikebukuro Shopping Mall in August this year. Cost me 2000Yen!  Fortunately, it manages to grow well under tropical conditions.