Rubus apetalus, Poiret, 1804

Beek, Abraham Van De, 2021, Rubi Capenses: a further contribution to the knowledge of the genus Rubus (Rosaceae) in South Africa, Phytotaxa 515 (1), pp. 1-71 : 24

i. Discussion on Rubus apetalus

After checking the types and many other specimens, it is clear that most of these species are not identical. It seems that they are often placed together because of missing or very small hidden petals, without due attention to the other characteristics. Only R. apetalus and R. borbonicus are the same species. Rubus madagascarius and R. quartinianus have very different habits from R. apetalus , but also R. exsuccus and R. adolfi-friedericii have clear distinguishing characteristics, though the distinctions are sometimes less sharp than with the species of the islands. After comparing many samples, most specimens can be identified without having checked the details.

The next question is if the South African plants can be identified with one or more of the species that were discussed above. Recent authors (Spies & Du Plessis 1985, 1986, Spies et al. 1985, 1987, Henderson 2011, Sochor 2019) accept the identity of all relevant specimens from South Africa with R. apetalus . Gustafsson (1934) was of another opinion and does not claim R. apetalus for the continent. He assigns most of the South African plants to R. ecklonii . This name will be dealt with in a separate species treatment below. Gustafsson (1934) also presumes that a specimen in B, which was probably destroyed, from Transvaal might be R. adolfi-friedericii .

The extant specimens from South Africa clearly differ from R. apetalus . Except for a specimen from Mpumalanga, the leaves are very characteristic. Leaflets are narrowly ovate or obovate, with a rounded or emarginate base, gradually attenuate into a rather long tip; serrature with (rather) fine roundish short mucronate teeth, often double, with 2–5 teeth compounded in a unit; adaxially the leaves have strigose hairs and abaxially rather long hairs; abaxially the leaves of the primocanes and the basal leaves of the flowering branch are greenish, not or only slightly tomentose and becoming greenish grey, while the upper leaves in the inflorescences can be grey or greyish white, with patent hairs between the tomentum. This is totally different from the leaves of R. apetalus , as described above, and from all other relevant species. The South African plants also have more robust and more curved prickles (except R. madagascarius , without further similarity) than the other species. The ovaries are slightly hairy on the apex when young, soon becoming glabrous, and thus different from the hairy ovaries of R. apetalus and the shiny glabrous ones of R. exsuccus . The South African plants also differ from R. exsuccus by short greyish brown hairs instead of long reddish-brown hairs. They differ from R. adolfi-friedericii by the serrature and shape of the leaves and larger inflorescences, longer sepals, and the presence of (small) petals.

It must be concluded that specimens from South Africa (except a few from Mpumalanga) do not correspond with any of the species mentioned above. Consequently, they are described as a new species, namely Rubus cryptopetalus A.Beek (see below).