Corylus maxima Mill.

Holstein, Norbert, Tamer, Sarah el & Weigend, Maximilian, 2018, The nutty world of hazel names - a critical taxonomic checklist of the genus Corylus (Betulaceae), European Journal of Taxonomy 409, pp. 1-45 : 25-27

12. Corylus maxima Mill.

The Gardeners Dictionary ed. 8 no. 2 ( Miller 1768). – C. tubulosa Willd. , Species Plantarum ed. 4 4 (1): 470 ( Willdenow 1805) nom. illegit. superfl. – C. avellana var. tubulosa Loudon, Arboretum et Fruticetum Britannicum 3: 2018, fig. 1943 ( Loudon 1838). – Original citation: Only a reference to Bauhin (1623: 418): “ Corylus sativa fructu oblongo,” which does not contain figures. – Type: not localized (No original specimen found in BM or K). – Note: Corylus maxima was recognized in the Flora of the USSR ( Bobrov 1936a), Flora Europaea and World Checklist and Bibliography of Fagales ( Govaerts & Frodin 1998) . The absence of both a physical specimen and the direct citation of an illustration (Art. 7.7, McNeill et al. 2012) makes the interpretation of this name difficult. The rather cryptic description of the stipules being intermediate between C. avellana and C. colurna makes it rather hard to understand the exact intention of the author. Miller wrote that “red and white Filberts, both which are so well known, as need no description” (and was definitely wrong in that point). Solely his citation of Bauhin’s descriptive name “ Corylus sativa fructu oblongo,” gives some indication of what was meant, but the most important character, the involucre of the nut, is not described by him. Miller’s idea of C. maxima is clearly connected to the filbert. The word is said to be either derived from “full beard” ( Loudon 1838; Goeschke 1887) or from an old English name ( Loudon 1838). There are two Saints of the name Philibert: Philibert of Jumièges, whose feast day is on 20 th August, and Philibert of Toledo, whose feast day is on 22 nd August (The Benedictine Monks of St. Augustine’s Abbey, Ramsgate 1921), both at the time when filberts are supposed to ripen ( Bunyard 1920). Filberts are generally regarded as having a long involucre, much exceeding the ripe nut in length. However, there are two morphs: 1) the involucre is often deeply split and the lobes are striate to reticulate and often bend outwards, and 2) a smooth tubular involucre enclosing the nut and producing a short beak with a laciniate apex, similar to what is found in C. chinensis . Brookshaw (1812, pl. 73) illustrates both kinds, the former as “Barcelona filbert” (also with an oblong nut) and the latter as “white and scarlet filbert.” The citations under Bauhin’s descriptive name all mention that Miller’s “filbert” is cultivated and that the fruit is oblong and is either white or red. White and red filberts were described separately as C. avellana var. alba Aiton and C. avellana var. rubra Aiton later-on, so Miller’s species includes different entities. The name C. tubulosa is superfluous, because Willdenow cited C. maxima in synonymy. Loudon accepted a hazel with a tubular involucre as a distinct and cited C. maxima and C. tubulosa as synonyms, though he adopted the later name. Since Loudon cited C. maxima Mill. fully, C. avellana var. tubulosa is to be interpreted as nomen novum. As there are no types of C. maxima , C. avellana var. tubulosa is not homotypic (illegitimate) with Aiton’s varieties C. avellana var. alba and C. avellana var. rubra . However, even Loudon did not have a clear image of C. maxima , as Loudon’s figure does not correspond to Willdenow’s specimens of C. tubulosa (B-W 17704-010!, B-W 17704-020!, B-W 17704–030!).

C. avellana var. sativa C.F.Ludw., Die Neuere Wilde Baumzucht : 14 ( Ludwig 1783) nom. nud.

C. avellana var. alba Aiton, Hortus Kewensis 3: 363 ( Aiton 1789). – C. alba (Aiton) Steud., Nomenclator Botanicus ed. 2 1: 424 ( Steudel 1840). – C. maxima var. alba (Aiton) C.K.Schneid., Illustriertes Handbuch der Laubholzkunde 1: 149 ( Schneider 1904). – Original citation: “ Corylus sativa fructu albo minore sive vulgaris ” ( Bauhin 1623). – Type: not localized. – Note: this name is only accompanied with the English common name, so it lacks a description itself, but it contains a validating description by Bauhin (1623; Art. 7.7, McNeill et al. 2012). As there are no corresponding specimens in either Kew or BM, nor a figure in Bauhin’s Pinax Theatri Botanici , there is no original material. The citations under the name “ Corylus sativa fructu albo minore sive vulgaris ” are ambiguous. They sometimes mention a round nut in contrast to the oblong nut typical of the filbert. This is in contrast to the citation of Dodoens’ C. hortensis (Dodoens 1757: 515) , to whom Bauhin also referred. Dodoens differentiates and illustrates two hazels, a wild one (a mirror image copy from Fuchs (1542: 398), which is the lectotype of C. avellana L.), and the domesticated one ( Fuchs 1542: 399). Dodoens’ cultivated hazel has a laciniate involucre, and he explicitly mentions the red pellicule (testa) of the nut. Bauhin also cites Fuchs’ Avellana domestica , although Fuchs clearly states “rubra membrana inclusus”, which appears to be in contrast to the “white” fruit of Bauhin’s name.

C. avellana var. rubra Aiton, Hortus Kewensis 3: 363 ( Aiton 1789). – C. rubra (Aiton) Borkh., Theoretisch Praktisches Handbuch der Forstbotanik 1: 723 ( Borkhausen 1800) nom. illegit. superfl. – C. maxima var. rubra (Aiton) C.K.Schneid., Illustriertes Handbuch der Laubholzkunde 1: 149 ( Schneider 1904). – C. maxima var. rubra f. normalis (Aiton) C.K.Schneid., Illustriertes Handbuch der Laubholzkunde 1: 149 ( Schneider 1904) nom. inval. (Art. 24.3, McNeill et al. 2012). – Original citation: “ Corylus sativa fructu oblongo rubente ” ( Bauhin 1623: 418). – Type: not localized. – Note: as for C. avellana var. alba , C. avellana var. rubra is only accompanied with the English native name, but it contains a validating description by Bauhin (Art. 7.7, McNeill et al. 2012). As there are no corresponding specimens in either Kew or BM, nor a figure in Bauhin’s Pinax Theatri Botanici , there is no original material. According to Bauhin’s phrase name, this taxon has oblong reddish nuts, corresponding to the red filbert of Miller (1768). Rea (1665) already described the “wellknown” filberts and indicates that the “red filbert” has a red testa, but he did not mention red leaves, although he discussed leaf characters for other names. Also Dodoens (1757: 515) mentioned a red pellicule. Therefore, the mention of the red color is thus not referring to the foliage, but the testa. The application and interpretation of Borkhausen’s C. rubra is confusing in this context, because the same descriptive epithet was published before, but it was eventually used to describe something different. In all cases, the authors deal with filberts (in the sense of C. maxima Mill. ) as they refer to the same Pre-Linnean polynomina by Bauhin. However, on the one hand, the epithet in C. avellana var. rubra Aiton (1789: 363) describes the red testa. On the other hand, Borkhausen understood the epithet to describe a plant with red or brownish leaves, while Aiton did not mention the leaves at all. A red-leaved filbert was mentioned by Du Roi (1771: 178) for the first time, but without giving it a valid name. When Du Roi dealt with Miller’s Corylus maxima , he distinguished white filberts and red filberts as did Miller and later Aiton; he even cited the same polynomina by Bauhin. But in contrast to Miller and Aiton (and any other author to our knowledge), already Du Roi understood his “red filberts” to have red or brownish leaves. Since there is no information on the leaf color of Miller’s and Aiton’s “red filbert”, it is doubtful whether Borkhausen actually meant his name to be something new. Even Goeschke (1887) mentions that the “Rote Lambertsnuss”/red filbert has slightly brownish leaves, while he accepted a purple-leaved filbert as something different. Corylus rubra is therefore interpreted best a new combination, because Borkhausen meant the same “red filbert” that also Miller and Aiton cited by using Bauhin’s polynomen, although Aiton and Borkhausen referred the epithet to different characters. Since Borkhausen does not discuss green-leaved filberts or cited any filberts under another name, there is no apparent intent to describe a new species but rather to use a better-fitting name. Therefore, Art. 41.4 ( McNeill et al. 2012) applies. However, Borkhausen’s new combination is illegitimate, as he also cites a “ Corylus maxima Münchh. ” in synonymy. The present authors are not aware of any publication of this name, but rather interpret this name as an “updated” citation. Münchhausen does not use Miller’s binomial in the third volume of his Der Hausvater ( Münchhausen 1768: 827), but refers to Miller’s polynomen ( Miller 1759) that Miller took up later. Münchhausen also did not publish that name when he dealt with hazelnuts again in the fifth volume of the Der Hausvater ( Münchhausen 1770: 142). He omitted the discussion of the filberts at all by referring to his publication in the third Hausvater volume. After Miller adopted the binomials in the eigth edition of his The Gardeners Dictionary and published C. maxima ( Miller 1768) , Borkhausen apparently updated Münchhausen’s description (who also did not mention red leaves). Nevertheless, Borkhausen makes an indirect reference to a published name on the same rank without excluding parts of it, rendering his C. rubra superfluous.

C. tubulosa var. oblonga Risso, Histoire Naturelle des Principales Productions de l’Europe Méridionale et particulièrement de Celles des Environs de Nice et des Alpes Maritimes 2: 332 ( Risso 1826). – Type: not localized.

C. intermedia Fingerh. , Linnaea 4: 384, tab. III fig. 4 (Fingerhuth 1829). – Original citation: “Wächst an schattigen Stellen bei Esch im Köllner Regierungs-Bezirk.” – Type: not localized.

C. sativa Poit. & Turpin, Pomologie Française Recueil des Plus Beaux Fruits Cultivés en France 4: tab.11 ( Poiteau 1846) nom. illegit. superfl. – Note: this name was published with C. tubulosa Willd. as a synonym. The plate also depicts the kind of hazel that is here considered to represent C. maxima . Poiteau and Turpin even show the dark red testa that was mentioned in literature cited by Bauhin on which C. maxima relies upon.

C. avellana var. viminalis Henriksson, Botaniska Notiser 1918 (6): 297 ( Henriksson 1918). – Type: Sweden, Dalia, paroecia Gunnarsnäs, in silva Hällan ad Mörtviken, J. Henriksson s.n. (holo-: not localized).

12a. Corylus maxima ‘ Purpurea ’

C. avellana var. purpurea hort. ex Loudon, Arboretum et Fruticetum Britannicum 3: 2017 ( Loudon 1838). – C. tubulosa [unranked] purpurea Audib. ex Mouill., Traité des Arbres & Arbrisseaux 2: 1142 ( Mouillefert 1891 –1898) nom. illegit. superfl. – C. maxima var. purpurea (hort. ex Loudon) Rehder, Manual of Cultivated Trees and Shrubs Hardy in North America: 154 ( Rehder 1927). – C. maxima ( var. rubra ) f. purpurea (hort. ex Loudon) C.K.Schneid., Illustriertes Handbuch der Laubholzkunde 1: 149 ( Schneider 1904). – C. maxima f. purpurea (hort. ex Loudon) Rehder , Bibliography of Cultivated Trees and Shrubs Hardy in the Cooler Temperate Regions of the Northern Hemisphere: 111 ( Rehder 1949). – C. purpurea A.DC., Prodromus Systematis Naturalis Regni Vegetabilis 16(2): 132 ( Candolle 1864) nom. inval. pro syn. – C. atropurpurea hort. ex Loudon, Arboretum et Fruticetum Britannicum 3: 2017 ( Loudon 1838) nom. inval. pro syn. – C. atropurpurea Booth et al. , James Booth & Söhne, Eigenthümer der Flottbecker Baumschulen bei Hamburg 1845: 45 ( Booth et al. 1845).– C. avellana var. atropurpurea (Booth et al.) G.Kirchn., Arboretum Muscaviense : 670 ( Petzold & Kirchner 1864). – C. tubulosa var. atropurpurea (Booth et al.) A.DC., Prodromus Systematis Naturalis Regni Vegetabilis 16(2): 132 ( Candolle 1864). – C. maxima f. atropurpurea (Booth et al.) Dippel, Handbuch der Laubholzkunde 2: 130 ( Dippel 1891) [“1892”]. – Type: not localized. – Note: this is a cultivar with dark red to purple leaves, but Loudon did not give any information on the involucre or the shape of the nut necessary for the differentiation between C. avellana and C. maxima . More complicating, Loudon did not differentiate between C. avellana and C. maxima at a species level. Loudon cited Loddiges’ Catalogue of Plants ed. 16 ( Loddiges 1836) as only source. Original material therefore came from commercial cultivation, and there is no physical material to our knowledge. Goeschke (1887: 79) reported that his “Rotblättrige Lambertsnuss” (“red-leaved Lambert’s hazel or Filbert”) was introduced as “ Corylus atropurpurea ” by the Pépinières Baumann in Bollwiller, Alsace, France in the 1820s. Loudon cited just this name (in synonymy to purpurea ), and it is therefore likely that Goeschke had the original cultivar in mind in his book. According to Goeschke’s description, this cultivar has purple leaves, a smooth tubular involucre, and the nut has a pale pink testa. This cultivar still exists under the name ‘Purple Aveline’. Red/purple foliage is apparently of a single origin in Corylus . Thompson (1985) reported that the locus for leaf coloration (A for anthocyanin) and the self-incompatibility “gene” were linked in Corylus , which is confirmed by Ives et al. (2014). The cultivars ‘Fuscorubra’ and ‘Rode Zeller’ have the S6 allele, while ‘Purple Aveline’ (Rotblättrige Lambertsnuss/ C. atropurpurea hort./ C. maxima ‘Purpurea’) has the alleles S5S10. The cultivar ‘Fuscorubra’ has a short bract husk, while ‘Rode Zeller’ has a long husk. In ‘Rode Zeller’, however, the husk is not long tubular, but the bract lamina is striate and presents the nut openly in contrast to C. maxima ‘Purpurea’. Both cultivars inherit the red leaf coloration ( Thompson et al. 1996), while C. maxima ‘Purpurea’/’Purple Aveline’ does not and is thus interpreted as graft hybrid on ‘White Aveline’, which is C. maxima / C. avellana var. alba . As Loudon cited the horticultural epithet atropurpurea in synonymy, it is a pro synonym of purpurea . As a horticultural variety (cultivar) it is best called C. maxima ‘Purpurea’, since this epithet is the oldest, unambiguously referable name to the cultivated plant (Art. 29.1, Brickell et al. 2009). However, it must be noted that the name “ C. maxima ” has been widely misapplied to a large- and round-fruited cultivar of C. avellana , and it was even validly published as C. avellana var. maxima for just that round-fruited cultivar. Bean’s C. maxima var. atropurpurea ( Bean 1898: 350) is such a case, and the described plant likely refers to a cultivar similar to ‘Rode Zeller’.