The achenes do not prove to coincide with those of O. junceum for they lack the three blunt, ridge-like processes at the apex, which are characteristic of the achenes in O. junceum, and moreover they are only about half as large as in O. junceum. With regard to the shape of the leaves the two species are easy to keep separate. In O. asperulum all the leaves are linear or narrowly oblanceolate-linear and sessile, while in O. junceum at least the lower and medial leaves of the stem are elliptic or broadly lanceolate, and conspicuously petioled. The leaves, younger branches and parts of the stem are as a rule asperous owing to very small raised points, as indicated by the specific name asperulum, but forms are also found which may be described as almost smooth. In contrast to O. junceum, the stem in O. asperulum is also branched in its lower and medial parts. The heads are usually disposed singly at the apices of the branches, but sometimes they form a few-headed, racemose inflorescence. In O. junceum, on the other hand, the heads are arranged in a corymbose or paniculate inflorescence.
Roughly hairy shrub to 1 m with suberect branches, thinly woolly on young parts. Leaves linear, ascending, margins scabrid and slightly toothed and thickened. Flower heads radiate, solitary or in lax corymbs, yellow, often copper on reverse. Achenes smooth.
Suffrutex erectus laxe ramosus usque 1 m altus; caulis et rami rigidi ± striato-sulcati foliati, internodiis plerumque 0.5-1 cm longis, partibus junioribus virides asperi-aculeolati vel rarius laeves, partibus vetustioribus cortice fusco vestiti. Folia alterna coriacea sessilia erectopatentia interdum leviter curvata ± asperula vel laevia linearia vel anguste oblanceolato-linearia 3-7 cm longa 0.2-0.6 cm lata acuta pungentia margine scabra integerrima vel saepe remote spinulosodenticulata; nervus medius subtus elevatus in ramum paullum decurrens. Capitula in apicibus ramorum solitaria vel pauca in racemum disposita; pedunculi capitulorum ± albido-lanati bracteis lineari-subulatis instructi. Involucrum turbinato-campanulatum 7-10 mm altum; squamae floccoso-lanatae partim glabrescentes virides anguste albidomarginatae apicem versus plerumque atro-purpureae imbricatae 2-3seriatae, exteriores triangulari-lanceolatae 3-5 mm longae acutae, interiores oblongae-obovatae basi latae apice acuto-acuminatae 6-8 mm longae (2-)3-4 mm latae. Flores radii c. 10 involucrum plus duplo superantes; ligulae luteae extus saepe partim cupreae. Flores disci lutei involucro paullo breviores. Achaenia glabra laevia vel basi leviter sulcata cylindracea-trigono-cylindracea 5 mm longa 2 mm lata.