Hook-Lobed Dandelion, Taraxacum hamatum (T. Section Hamata: Asteraceae) in Vermont

Abstract

In May 2020, in connection with a project to familiarize myself with the nonnative dandelions (Taraxacum F. H. Wigg.) in the flora of Vermont, I encountered a population of a very distinctive dandelion in a meadow in Hardwick, Caledonia County. Upon study with relevant literature and illustrations (Dudman and Richards 1997; Richards 2012; Richards and Sell 1976; Stace 2019; Trávníček and Vašut 2011), I determined it to be T. hamatum Raunk. (Figure 1). Voucher specimens were collected and are deposited at MT, NEBC, and VT. Taraxacum hamatum Raunk., Dansk Exskurs.-Fl., ed. 2: 225 (1906) was based on a type from Denmark: Sjaelland (Zealand), Jonstrup Væng, skoveng [forest], 14 May 1905, Raunkier s.n., lectotype at C (C10021066), chosen by Øllgaard, not seen. An image of the lectotype specimen was published by Øllgaard (1983); an image of a duplicate (S10-38037) is available on JSTOR Global Plants (2020). Excellent illustrations may be found in Dudman and Richards (1997), Richards (2012), and Trávníček and Vašut (2011). Relevant characters for identification, to which this collection fully conforms, include the following: