The hybrid Anemonoides nemorosa × A. ranunculoides is recorded for the first time in Italy at the southern periphery of Bologna (N Italy, Emilia-Romagna). Its status is supported by both morphological features and chromosome number (2n = 31). For this taxon, a new nomenclatural combination is proposed.

chromosome number, hybrid, vascular flora

Anemonoides nemorosa (L.) Holub is a circumboreal species, quite common in woods and clearings throughout the Alps and peninsular Italy. Anemonoides ranunculoides (L.) Holub occurs in Europe and the Caucasus area, and is widespread in the forests of northern Italy, but increasingly rare to the south (Pignatti 2017; Bartolucci et al. 2018).

Natural hybrids among these species have been described since the first half of the nineteenth century for several areas of Austria, Germany, Denmark, and Sweden (Pritzel 1841; Beck von Mannagetta 1890; Camus 1898; Hegi 1912; Bernström 1946).

Since 2012, morphologically intermediate individuals have been known at the southern periphery of Bologna, N Italy (Fig. 1), where A. nemorosa and A. ranunculoides co-exist. Given that the first species shows typically 2n = 30 and the second 2n = 32 chromosomes (Mlinarec et al. 2012), we expect that putatively F1 hybrid plants should show 2n = 31, as reported by Bernström (1946) for Sweden.

Figure 1. 

Anemonoides nemorosa (L.) Holub (A), A. ranunculoides (L.) Holub (C) and their putative hybrid (B) from Via di Roncrio, Bologna, N Italy. March 2017. Photo by L. Peruzzi.

Results of morphological observations are reported in Table 1. For all the features evaluated, the putative hybrid shows intermediate values between those of putative parental species.

The putatively hybrid plants show 2n = 31 chromosomes.

The morphological features of the plants studied agree perfectly with those reported for the hybrid A. nemorosa ×A. ranunculoides from Saxony-Anhalt, NE Germany, ca. 200 km N-NW to Leipzig (Brennenstuhl 2004). Our chromosome count carried out on the Italian population, 2n = 31, also agrees with previous counts based on extra-Italian material (Bernström 1946).

The circumscription of tribe Anemoninae has been much controversial in recent years, and a wide array of taxonomic solutions were proposed, ranging from the inclusion of a number of morphologically well-established genera in a large and highly heterogeneous Anemone (Hoot et al. 2012), to the disintegration of the traditional concept of Anemone in a number of smaller genera (e.g., Mosyakin 2016; Bartolucci et al. 2018; Christenhusz et al. 2018) to allow the recognition of monophyletic groups. Among the scholars favouring this latter approach, the taxonomic independence of the genus Anemonoides Mill. (= Anemone sect. Anemonanthea DC.) is disputed by some authors preferring a wider concept of Anemone (e.g., Ziman et al. 2008; Mosyakin 2016; Pignatti 2017). On the contrary, other authors as Starodubtsev (1991), Banfi et al. (2005), and Bartolucci et al. (2018) recognize it as a distinct genus, an option we also follow here. Under Anemonoides, the hybrid A. nemorosa × A. ranunculoides has been named A. × seemenii (E.G.Camus) Holub so far (Holub 1983). However, the name holding priority at (notho-)species level is Anemone × lipsiensis Beck, so that the following new combination is needed under that genus: