1	"Apically swollen shoulders or horns of cypselas with at least a few hairs"	2
1	"Apically swollen shoulders or horns of cypselas glabrous – note that hairs extending from lateral gap (cleft) may overlap shoulders"	3
2	"Ab/adaxial margins with prominent tubercles; pappus absent, but a small abscission zone from the corolla may be evident"	"Roebuckiella halophila"
2	"Ab/adaxial margins of cypselas smooth except for a few hairs and their minute bases; pappus present, crown­like, c. 0.4–0.7 mm long"	"Roebuckiella lathamensis"
3	"Gap on lateral surfaces of cypselas with tubercles or at least some cypselas in a capitulum with at least part of the ab/adaxial margins dissected or with prominent tubercles"	"Roebuckiella cheilocarpa"
3	"Gap on lateral surfaces and the ab/ad margins of cypselas lacking tubercles, the ab/adaxial margins essentially entire (minor swellings at base of hairs may be present)"	4
4	"Eglandular hairs on cypselas apically straight"	"Roebuckiella cuneata"
4	"Eglandular hairs on cypselas apically curling"	5
5	"Apex of lateral surfaces of cypselas with a prominent horn­like extension"	6
5	"Apex of lateral surfaces of cypselas rounded and variably swollen"	7
6	"Pappus minute and crown­like, individual elements 0.08–0.28 mm long; lateral gap of cypselas with a few scattered hairs; ab/adaxial margins of cypselas with hairs along their length"	"Roebuckiella chinnockii"
6	"Pappus crown­like, 0.5–1 mm long; lateral gap of cypselas with a prominent cover of hairs; ab/adaxial margins of cypselas glabrous or only with 1–several basal hairs"	"Roebuckiella nerrenensis"
7	"Lateral surfaces of cypselas with scattered eglandular hairs which may be appressed to somewhat spreading and neither they nor any hairs on the ab/adaxial margin overlapping with the pappus or cypselas glabrous; leaves and stems commonly with a prominent indumentum of stalked glandular hairs or plants glabrous or almost so"	"Roebuckiella similis"
7	"Lateral surfaces of cypselas with a prominent cover of somewhat appressed hairs obscuring most of the gap; the apices of the upper hairs in the lateral gap and/or those on the apices of the ab/adaxial margins distinctly overlapping with the pappus; leaves and stems mostly glabrous, eglandular septate hairs usually about the base of leaves but stalked glandular hairs few or absent"	8
8	"Eglandular hairs on cypselas 0.25–1.8 mm long, those on the lateral surfaces and (when pre­sent) those on the upper ab/adaxial margins of the cypselas usually manifestly overlapping with pappus bristles; bracts apically subobtuse"	"Roebuckiella ciliocarpa"
8	"Eglandular hairs on cypselas c. 0.8 mm long, those on the lateral surfaces usually not or barely reaching apex of the shoulder, only those hairs on the upper ab/adaxial margins about level with the pappus; bracts apically obtuse to somewhat acute"	"Roebuckiella oncocarpa"