Kunkeliella

García, Miguel A., Mucina, Ladislav & Nickrent, Daniel L., 2024, A tough nutlet to crack: Resolving the phylogeny of Thesium (Thesiaceae), the largest genus in Santalales, TAXON 73 (1), pp. 190-236 : 200

4. Kunkeliella clade (BIPP 1).

— This clade ( Fig. 2A ), composed of endemics to the Canary Islands archipelago, was formerly placed in the genus Kunkeliella ( Stearn, 1972) and members were reclassified as Thesium sect. Kunkeliella by Forest & Manning (2013). Two species were sampled here: T. subsucculentum (Kämmer) J.C.Manning & F.Forest ( Fig. 3B ) from the north coast of Tenerife (Canary Islands, Spain) and T. retamoides (A.Santos) J.C.Manning & F.Forest from the southern part of the same island. The three ITS clones of T. subsucculentum (A, B, C) and two clones of T. retamoides (A, B) were not monophyletic based on species. However, Rodríguez-Rodríguez & al. (2022) found enough genetic variation based on microsatellite markers to consider them different species, a conclusion also supported by morphology. On Tenerife, all the species have stems covered with an indument of tiny hairs, whereas T. canariense (Stearn) J.C. Manning & F.Forest , endemic to Gran Canaria Island, is glabrous. Otherwise, the flowers, fruits and general habit of these plants are similar except for the smaller flowers of T. canariense . That species is the only one in the genus known to be gynodioecious, i.e., with bisexual and female flowers on separate plants ( Pérez de Paz & al., 2015). Stearn (1972) considered this a genus separate from Thesium based mainly upon its possession of isopolar pollen and drupaceous fruits. Isopolar pollen is of questionably diagnostic value as it has been found in several South African species of Thesium plus intermediates between heteropolar and isopolar pollen types are known ( Lobreau-Callen, 1980). Fleshy fruits are also present in T. fragile L.f., T. triflorum and T. radicans .

Unsampled species include Thesium canariense from Gran Canaria and T. psilotocladum Svent. from Tenerife (extinct). Recently, a new species, T. palmense P.Pérez & P.Sosa , was described from La Palma, closely related to T. retamoides from Tenerife.

Figures

Fig. 2. Phylogenetic analysis of Thesium using nuclear ribosomal internal transcribed spacer (ITS) sequences. This tree, rooted with Osyridicarpos and Lacomucinaea (outgroups) gives Bayesian posterior probabilities at the nodes. Clades discussed in the text are numbered. Geographical sources for the sampled taxa are abbreviated as follows: AFN = Northern Africa, AFS = Southern Africa, AFT = Tropical Africa, ASC = Central Asia, ASE = Eastern Asia, ASN = Northern Asia, ASS = Southern Asia, ASW = Western Asia, AUS = Australia, CIS = Canary Islands, EUR = Europe, MAD = Madagascar, SAM = South America, and USA = United States of America.

Fig. 3. Caption on next page.