This species is characterized by its rather robust habit, pedunculate branched inflorescences with the axes generally elongated and monochasial, 5-merous flowers, shallowly lobed calyx limbs, corolla tubes 7-18 mm long, and capsules 40-100 x 3-4 mm. The inflorescence axes are often flexuous to markedly cincinnate. Joosia umbellifera was circumscribed much more broadly, in particular in terms of mophological variation by both Steyermark and Andersson than done here (Taylor, 2017). Several species they synonymized are separated here and appear to replaced Joosia umbellata in particular regions; see the discussions of these other species for their separation from Joosia umbellifera.
Joosia umbellifera is replaced in northern Peru (Amazonas) by Joosia dielsiana, also with a shallowly lobed calyx limb but with shorter capsules. Joosia umbellifera is replaced in southern Central America and western Colombia by Joosia panamensis, with shorter inflorescence axes. Joosia umbellifera was also circumscribed by Andersson (1997) to include Joosia ulei, which has smaller 4-merous flowers. Andersson also included Ladenbergia dichotoma var. calycina within his circumscription of Joosia umbellifera, but that other plant has deeply lobed longer calyx limbs and that name is here synonymized with Joosia sericea.