Narrowly (neo)endemic species often attract special attention in conservation contexts, because their restricted distributions render them more vulnerable than most widespread species. However, little attention is given to the question whether time since speciation is the (only) factor responsible for the narrow ranges of neoendemics, or if biological or ecological factors are (also) involved. The Southeast Asian orchid genus Sirindhornia comprises three terrestrial species. In Thailand, we compared demographic and reproductive characteristics between the local endemics S. mirabilis and S. pulchella and the widespread S. monophylla. The three species had similar demographic characteristics, but different reproductive attributes. In most contexts where they differed, the local endemics were more reproductively restricted than the widespread S. monophylla. Thus, the latter exhibited higher relative fruit set, higher seed production per inflorescence and more equal individual contributions of progeny. However, recruitment appeared to be more efficient in S. pulchella than in the other two species.