E. Crow et al., LEAF ANATOMY OF THE GENUS PSORALEA-SENSU-STRICTO (PSORALEEAE, PAPILIONOIDEAE, LEGUMINOSAE), Biological Journal of the Linnean Society, 124(2), 1997, pp. 155-182
Leaf anatomy is described from 17 species of Psoralea sensu which incl
udes four species of the genus Hallia Thunberg. Species of the two gen
era share many characters including the presence of rod-shaped crystal
s, similar stipule structure and a possible continuum in secretory cav
ity anatomy ranging from a small and non-trabeculate to a large and tr
abeculate form. Hallia species are distinguished by the presence of la
rge tannin cells in the bundle sheaths and a narrow length:width ratio
of palisade cells. In the light of other floral evidence this is cons
idered insufficient to separate the two genera, a view confirmed by cl
uster analysis. Thus, Salter's proposal of 1939 for their amalgamation
is supported. Leaf anatomy of herbaceous species is compared with tha
t of seedlings of Psoralea sp. to assess the possibility that the herb
aceous species may have arisen through neoteny from species that are t
rees or shrubs. Comparative venation studies between stipules and scal
e leaves suggest that the scale leaf form arose from pinnate-leaved an
cestors by leaf reduction. (C) 1997 The Linnean Society of London.