The family Thelypteridaceae characteristically has monolete, bilateral spores with a well developed, variously folded perine. Trilete, tetrahedral spores have been reported so far in only one species of Lastrea, L. ciliata Hooker (Nayar & Chandra, 1966-67). Ching (1933), however, wrongly reported tetrahedral spores in the genus Sphaerostephanos, another genus of the Thelypteridaceae. During studies of thelypteroid ferns, I observed typically trilete, tetrahedral spores in L. tenericaulis Moore. The spores were studied from plants growing in the fernery of the National Botanic Gardens as well as from specimens collected in the Western Ghats of South India. In both cases, trilete, tetrahedral spores were mixed with bilateral ones and with some intermediate in form.