Introduction
When working on an updated catalogue of gymnosperms, we noticed that the small-seeded juniper has nomenclatural problems. The small-seeded juniper was treated either as a species, e.g., Juniperus microsperma (W.C.Cheng & L.K.Fu) R.P.Adams (Adams 2008, 2014; Shang et al. 2015), Sabinamicrosperma (W.C.Cheng & L.K.Fu) W.C.Cheng & L.K.Fu (Fu 1983, in Fl. Xizang. 1: 390), or a variety, e.g.,Sabina convallium var. microsperma W.C.Cheng & L.K.Fu (Cheng et al. 1975; Wang et al. 1978), Juniperus convallium var. microsperma (W.C.Cheng & L.K.Fu) Silba (Silba 1984; Fu et al. 1999; Farjon 2010). However, it remained ambiguous whether these scientific names used in previous taxonomic works were validly published.
Sabina convallium var. microsperma W.C.Cheng & L.K.Fu was first recognized and described in Cheng et al. (1975, Acta Phytotax. Sin. 13: 86), but was not validly published in that work under Art. 35.1 of the Shenzhen Code (Turland et al. 2018), because the specific name Sabina convallium (Rehder & E.H.Wilson) W.C.Cheng & W.T.Wang was not validly published at that time. W.C.Cheng & W.T.Wang made the new combination Sabina convallium (Rehder & E.H.Wilson) W.C.Cheng & W.T.Wang (Cheng 1961, in Trees of China, 1: 257), but they did not validly publish the combination under Art. 41.5 because this combination was made after Jan. 1st of 1953 and the authors cited only the basionym but without the reference citation. W.C.Cheng & W.T.Wang unintentionally but validly published the specific combination in Flora Reipublicae Popularis Sinicae (Wang et al. 1978, 7: 372) where they correctly cited the basionym and its reference. In the same work, the varietal name Sabina convallium var. microsperma W.C.Cheng & L.K.Fu was validated by citing the reference of the protologue (Wang et al. 1978, 7: 373).
There are a few later names based on the invalid name Sabina convallium var. microsperma W.C.Cheng & L.K.Fu (Cheng et al. 1975). In 1983, W.C.Cheng & L.K.Fu intended to make a new combination Sabinamicrosperma (W.C.Cheng & L.K.Fu) W.C.Cheng & L.K.Fu (Fu 1983, Fl. Xizang. 1: 390), but they cited the invalid name Sabina convallium var. microsperma W.C.Cheng & L.K.Fu as the basionym and its publication in 1975. Silba (1984) made a new combination Juniperus convallium var. microsperma (W.C.Cheng & L.K.Fu) Silba based on the invalid name Sabina convallium var. microsperma W.C.Cheng & L.K.Fu (Cheng et al. 1975); Adams (2000) treated it as a species in Juniperus making the combination Juniperus microsperma (W.C.Cheng & L.K.Fu) R.P.Adams based on the same invalid basionym. Under Art. 41.6, all these combinations are valid though the reference of the basionym should be corrected.
Adams (2008, 2014) divided Juniperus into three sections, viz. sect. Caryocedrus Endl., sect. Juniperus, and sect. Sabina (Mill.) Spach, and indicated that the three sections can be distinguished using morphological characters, e.g. leaves decurrent or not (decurrent in sect. Sabina vs. jointed in sect. Caryocedrus and Juniperus), leaf shape (acicular in sect. Caryocedrus and Juniperus vs. scale-like in sect. Sabina), seed cones size (8–25 mm in sect. Caryocedrus vs. 6–18 mm in sect. Juniperus and Sabina), seeds fusion (fused in sect. Caryocedrus vs. free in sect. Juniperus and Sabina). Mao et al. (2010) suggested that all of the three sections are monophyletic. Yang et al. (2022) treated Sabina as a separate genus from Juniperus considering phylogeny, morphology, and utilization purposes. Based on the phylogeny of nuclear markers, Shang et al. (2015) suggested that Juniperus microsperma is not closely related to J. convallium, but sister to a small clade including J. semiglobosa and J. sabina. Therefore, we treated the generic name Sabina and the specific name Sabinamicrosperma as accepted.