PUSILLUM Michaux, 1803
Synonyms :
Diamorpha pusilla (Michaux) Nuttall (1818) / Tetrorum pusillum (Michaux) Rose (1905)
Tillaea cymosa Nuttall (1818) / Diamorpha cymosa (Nuttall) Britton ex Small (1903) / Sedum cymosum (Nuttall) Fröderström (1936)
Distribution : E USA (S. Appalachian Highlands); granite outcrops in shallow soil, 130 - 170 m.
Description (according to 't Hart & Bleij in IHSP, 2003) :
Small annual herbs with erect finely ribbed stem and extremely long hypocotyl (to 40% of the total height).
Leaves alternate, elliptic-oblong (ovate or lanceolate), rounded, minutely papillose at the tip, short-spurred, shortly petiolate, 1.6 - 4.3 x 1.1 - 1.8 mm, light green, lower leaves caducous.
Flowering branches erect, simple or branched, 2.3 - 5.8 cm.
Inflorescences terminal cymes or single flowers, bracts leaf-like, pedicels ± 2 mm, continuous with the calyx tube.
Flowers (3- to) 4- (to 7-) merous, sepals broadly sessile, broadly ovate to reniform, rounded, ± 0.5 x 1 mm, green, petals free, ovate-elliptic, obtuse, slightly channelled, white, 1.4 - 3.4 mm, divergent, filaments white, anthers dark red.
Cytology : 2n = 8