Brassaiopsis spinosissima Esser is described as a new species from Peninsular Thailand. It is compared with similar species from
Thailand (Brassaiopsis ciliata Dunn and B. griffithii C.B.Clarke) and Peninsular Malaysia (B. sumatrana Ridl.). They are primarily
distinguished by differences in inflorescence size and position and in details of the indumentum. Two names sometimes confused
with the new species, Panax palmatus Roxb. and Hedera polyacantha Wall., are lectotypified and discussed in connection with
Brassaiopsis hainla (Buch.-Ham. ex D.Don) Seem. in order to distinguish them from the new species.