Rotala sp. "Long Leaf"

This Rotala appeared in the trade in Europe in about 2010 or 2011 at the latest. A Dutch mail-order retailer calls it Rotala wallichii / long leaf. It is apparently identical to a plant that is passed on in Germany as Rotala cf. occultiflora. In a comparative cultivation in an aquarium at the company Aquasabi (early 2013) it could not be distinguished from the plant designated R. cf. occultiflora.

Online shops state that the plant comes from Southeast Asia. We have no more precise information about its original origin. It is also not clear whether the plant has definitely been identified as Rotala wallichii. It is much more similar to Rotala sp. "Nanjenshan" than to the conventional R. wallichii. As long as its species identity has not been clarified, it is not counted here as R. wallichii, but is marked with "sp." as an unidentified Rotala.

The designation Rotala cf. occultiflora was chosen because the plant resembles a locality variant of Rotala occultiflora in a photo from the Australian aquatic plant nursery Aquagreen. Whether Rotala sp. "wallichii Long Leaf" really belongs to the species R. occultiflora could only be proven with emersed, flowering and/or fruiting plants.

R. sp. "wallichii Long Leaf" differs only little from the mentioned Rotala sp. "Nanjenshan" as a submersed plant. Under the same conditions it tends more towards upright growth and is somewhat darker or more brownish or reddish in colour. Depending on light and nutrient conditions, the leaves are light or medium green to yellowish or brownish green on the upper side; the underside of the leaf is pink. The submersed leaves are linear, up to approx. 1 mm wide, approx. 1.5-2.3 cm long and taper slightly towards the leaf tip. The leaves are whorled, with approx. 3 to 5 leaves at each stem node. The leaf tip has a small notch, as in other fine-leaved Rotalas.

- To be continued -