North American species of Rubus L. (Rosaceae) described from European botanical gardens (1789-1823)

Native Rubus were brought from North America to European botanical gardens in the 18th and early 19th centuries, and some were described as new species. Limited knowledge of Rubus in that era, typically combined with brief descriptions, led to many incorrect interpretations, causing much confusion (especially in North America). We established a project to clarify the identity of these confusing species by reviewing types and descriptions along with comparative work involving modern collections. We identified seven putative North American Rubus species named from early European garden collections: R. villosus Aiton, R. vulpinus Poir., R. pensilvanicus Poir., R. flagellaris Willd., R. inermis Willd., R. heterophyllus Willd., and R. argutus Link, and four other names in the early European botanical literature of possible North American origin: R. decumbens Thunb., R. inermis Thunb., R. enslenii Tratt., and R. floridus Tratt. We affirmed the current applications of R. flagellaris, R. argutus, and R. enslenii. Rubus villosus is identical with R. leviculus L.H. Bailey, while the taxon to which R. villosus was generally applied in the 19th century, R. allegheniensis Porter, appears to be identical with R. vulpinus. Rubus heterophyllus Willd. was identified as an earlier name for R. plicatifolius Blanch. Rubus inermis Willd. is identical with R. ulmifolius Schott and must have originated in the Old World. Thunberg’s other American Rubus, R. decumbens, can be identified as R. arundelanus Blanch. Rubus floridus remains a puzzle. If its type represents a sample of a determinate flowering branch from a large, mounding dewberry, it is closest to R. grimesii L.H. Bailey, but it could also have been taken from a side-branch from an unknown upright blackberry. Another name for which identity could not be definitively established is R. pensilvanicus. It is allied with R. allegheniensis, but its type is insufficient to determine if it is an extreme form of that species, a related taxon, or a hybrid of it with a species of section Arguti (Rydb.) L.H. Bailey. We propose the name, R. revealii sp. nov. for the corymbose to weakly racemose Arguti previously considered as R. pensilvanicus sensu L.H. Bailey. Herein, we lectotypify R. abactus L.H. Bailey, R. arundelanus, R. decumbens, R. grimesii, R. inermis Thunb., R. invisus (L.H. Bailey) Britton, and R. vulpinus, and designate neotypes for R. argutus and R. heterophyllus.This peer reviewed article is published as Van de Beek A. & Widrlechner M. P. 2021. North American species of Rubus L. (Rosaceae) described from European botanical gardens (1789-1823). Adansonia, sér. 3, 43 (8): 67-98. https://doi.org/10.5252/adansonia2021v43a8

Rubus pensilvanicus Poir. (Poiret 1804

<i>Rubus pensilvanicus</i> Poir. <p> In <i>Encyclopédie méthodique, Botanique</i> 6: 246 (Poiret 1804).</p> <p> <i>R. abactus</i> L.H. Bailey, <i>Gentes Herbarum</i> 2: 452 (Bailey 1932).</p> <p> — Lectotype (here designated), selected by James L. Reveal, 2013 (presumably based on a statement in Bailey [1945: 718]): Connecticut Hill, Ithaca, Tompkins County, New York, 1.VIII.1925, <i>L.H. Bailey 2000</i> (lecto-, BH [BH 000 078 925, BH 000 078 928]) (Fig. 6A, B).</p> <p>HOLOTYPE. — P00320321 (P-JU 14 335).</p> <p>FINDINGS</p> <p>The description by Poiret is based on a specimen in the collection of Jussieu. Consequently, since it is extant, this must be considered the holotype (P00320321). As was typical in that era, it only consists of a floricane.</p> <p> This name was not used for any American bramble until Bailey received a photo of it from M.L. Fernald (Bailey 1945: 704) and identified it with plants that he found at many locations in the eastern United States (Bailey 1945: 702-704). Consequently, <i>R. pensilvanicus</i> suddenly became a rather common species. Bailey (1945: 699) treated <i>R. pensilvanicus</i> as a member of the <i>Arguti</i>. Fernald (1950: 861) and Davis <i>et al.</i> (1969b: 262) followed him in that regard. Notably, Alice <i>et al.</i> (2014) treated essentially all members of section <i>Arguti</i> under this name, believing it to be the oldest name for the pubescent, highbush blackberries lacking stipitate glands, which comprise this section.</p> <p> However, Bailey based his identification only on a photo, one of insufficient resolution to notice the finest details. Thierry Deroin (P) checked Poiret’s type carefully and noted that it bears very short stipitate glands on its pedicels and also some on the inflorescence axis, along with a few longer stipitate glands. This observation was confirmed by high-resolution photos that he sent to us. Consequently, the type does not belong to the <i>Arguti</i> but instead to the <i>Alleghenienses</i>. In sharp contrast, Bailey (1945) made no mention of any glandular trichomes in his detailed description of <i>R. pensilvanicus</i>, consistent with his placement of it within the <i>Arguti.</i></p> <p> So, in a single publication, Poiret (1804) named two species that fall within the <i>Alleghenienses</i>: <i>R. vulpinus</i>, which clearly displays the stipitate glands that are a key character of that section and otherwise conforms to the plant widely known as <i>R. allegheniensis</i>, and <i>R. pensilvanicus</i>, with its sparse glandularity less typical of <i>R. allegheniensis</i>. Such a plant might even represent an intersectional hybrid or be an earlier name for <i>R. abactus</i> L.H. Bailey. <i>Rubus abactus</i> has been treated as a close ally of <i>R. pensilvanicus</i> within the <i>Arguti</i> (keying out in the same couplet in Davis <i>et al.</i> 1969b), but a careful examination of the type of <i>R. abactus</i> revealed that it also bears short stipitate glands on its pedicels, along with a few longer stipitate glands on its inflorescence axis, as well as having coarser, jagged leaf serrations.</p> <p> If the type of <i>R. pensilvanicus</i> were more complete, we might be able to place <i>R. abactus</i> in synonymy under it, but there are at least two other options that cannot be fully evaluated without access to both well-developed primocane and floricane samples of <i>R. pensilvanicus</i>. First, it is possible that the <i>R. pensilvanicus</i> type represents a weak specimen of <i>R. allegheniensis</i>. Under suboptimal growing conditions, <i>R. allegheniensis</i> can produce smaller, weaker racemes that are atypical and may display few stipitate glands. Alternatively, in contrast to many apomictic North American blackberries, <i>R. allegheniensis</i> is typically sexual (Aalders & Hall 1966; Thompson 1997) with the ability to hybridize with other sympatric taxa. If such hybrids involve <i>Arguti</i>, the progeny could present intermediate characteristics.</p> <p> If one takes a very broad view of <i>R. allegheniensis</i>, with its considerable variation generated by being primarily a sexual diploid (Aalders & Hall 1966; Thompson 1997), potentially either of Poiret’s names from the 1804 publication could be selected for designating the correct name. However, there are two strong arguments to select <i>R. vulpinus</i>. First, it is a typical representative of the species, while <i>R. pensilvanicus</i> is marginal by virtue of its ambiguous trait expression. Second, the name <i>R. pensilvanicus</i> has been in wide use in eastern North America since 1945 for non-glandular highbush blackberries, and its selection would cause considerable confusion if it would be applied to a common species in the same region, while <i>R. vulpinus</i> has never been so used. So <i>R. vulpinus</i> could be indicated as the correct name for the taxon which has long been called <i>R. allegheniensis</i> Porter. However, because the name <i>R. allegheniensis</i> has been in use for a long time for a very common species, one which is also widely cultivated, a change of name is not desirable. Thus, we plan to submit a proposal for its conservation.</p> <p> Because of its glandular character, <i>R. pensilvanicus</i> does not belong to the <i>Arguti</i>. Consequently, if the <i>Arguti</i> are considered as one species, asAlice <i>et al.</i> (2014) did, the correct name of that species would be <i>R. argutus</i> Link, because this is the oldest of the legitimate names in that section.</p> <p> A subsequent question is what must be the correct name of the taxon which was called <i>R. pensilvanicus</i> by Bailey and later authors who followed him. Neither Bailey (1945) nor Davis <i>et al.</i> (1969b) mentioned any synonym and we, too, could not find one. Consequently, a new name must be given to it. In order to avoid any further confusion, we describe this taxon as a new species of section <i>Arguti</i> and not as a new name for <i>R. pensilvanicus</i> sensu L.H. Bailey. We chose the name <i>Rubus revealii</i> sp. nov. to honor the late James Reveal (Miller 2015), who contributed much to the knowledge of <i>Rubus</i>, not only of its American species but also its infrageneric taxa.</p>Published as part of <i>Van de Beek, Abraham & Widrlechner, Mark P., 2021, North American species of Rubus L. (Rosaceae) described from European botanical gardens (1789 - 1823), pp. 1789-1823 in Adansonia (3) (3) 43 (8)</i> on pages 77-79, DOI: 10.5252/adansonia2021v43a8, <a href="http://zenodo.org/record/4680762">http://zenodo.org/record/4680762</a&gt

Contributions from the Gray Herbarium of Harvard University

no. 165-173 1947-5