I am slightly confused. You are writing that "Dr. Almeida's flora has put S. colais (Buch. - Ham ex Dillw.) as the earlier name for S. personatum (Hassk,)" so logically former should be the correct name and not the latter that you have put in your subject line. According to GRIN also S. colais (Buch.-Ham. ex Dillw.) Mabb. is the correct name. There are two things to support it, firstly Mabberly has made his combination in 1978, whereas as Chatterjee made his in 1948, former is more recent. Secondly basionym Bignonia colais (1837) antedates Dipterosperma personatum Hassk. (1842), and hence if the two species are to be treated as synonyms, S. colais is preferred choice as correct name.
Dr. Gurcharan Singh
Retired Associate Professor
SGTB Khalsa College, University of Delhi, Delhi-110007
Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018.
Phone: 011-25518297 Mob: 9810359089