Lacomucinaea

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

0. Lacomucinaea clade (BIPP 1).

— Lacomucinaea lineata (L.f.) Nickrent & M.A.García ( Fig. 3A ), previously known as Thesium lineatum , was classified as a distinct genus by Nickrent & García (2015) based on molecular and morphological evidence. This genus is sister to Osyridicarpos and that clade is sister Thesium , relationships with the highest support from both ITS and the chloroplast genes ( Fig. 2A ). One may ask why Lacomucinaea was not included within Osyridicarpos . These two genera share several morphological features, e.g., primary phloem fiber bundles near the stem surface, bisexual flowers, lack of a swollen pedicel, and fleshy fruits with smooth exocarps. They differ in other characters such as habit (shrub vs. scrambling subshrub), leaf morphology, leaf persistence, inflorescence structure, presence of external floral gland, style length and ribbing on ovary. Four species have been described in Osyridicarpos although it is frequently treated as monotypic ( O. schimperianus ). Further studies might prove that several species should be recognized in the genus, all of them very different from Lacomucinaea . Thus, the preponderance of molecular and morphological evidence justifies recognition of two genera.

Figures

Fig. 3. Caption on next page.

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.