Rubus floridus Tratt.

Van de Beek, Abraham & Widrlechner, Mark P., 2021, North American species of Rubus L. (Rosaceae) described from European botanical gardens (1789 - 1823), Adansonia (3) 43 (8), pp. 1789-1823 : 88

Rubus floridus Tratt.

( Fig. 11 )

In Rosacearum monographia 3: 73 ( Trattinnick 1823).

R. argutus var. floridus (Tratt.) L.H. Bailey, Sketch of the Evolution of our Native Fruits: 370, 385 ( Bailey 1898).

HOLOTYPE. — Enslen, ‘ 1822 I, R. floribundus [sic!] Tratt., Amer. bor. Enslen’, W ( W0079959 ).

FINDINGS

Bailey obtained both a photo and a drawing of the type (both printed in Bailey 1923: 194 f, the drawing also in Bailey 1898: 382). Initially (1898), he considered it as a variety of R. argutus . Later he dealt with it as a separate species. Though he noted that the specimen has some glands, he inserted it in a group of mainly glandless brambles under the name Floridi ( Bailey 1923: 193), later identified with the Frondosi ( Bailey 1923: 265, 268). Finally ( Bailey 1943: 603), he postponed his efforts to identify it. So did Davis et al. (1969b), who wrote they considered it as a nomen nudum (obviously meaning ‘ incertum ’ or ‘ ambiguum ’, since the species was validly published).

Though Davis et al. (1969b) discussed R. floridus under the Arguti, they suggested that it might fit better within the Alleghenienses because Trattinnick (1823) explicitly mentioned its glands. We examined a high-resolution image of the type ( Fig. 11 ), and it does bear long stipitate glands. If R. floridus is truly a highbush blackberry, this would support Davis et al. ’s (1969b) suggested transfer to Alleghenienses.

Before accepting this option, the possibility that it belongs to another section, especially the Procumbentes, must be excluded. Though Trattinnick (1823) wrote that the stems are ‘recti’; Bailey (1945: 604) might have been correct when he stated that this only means straight, not erect. However, the way the inflorescences are positioned on the floricane makes clear that the stem was more-orless erect. On procumbent canes, the angles relative to the subtending cane would not have been so acute. The inflorescences were growing in the same direction as the stem. Consequently, the type was most likely collected from a highbush blackberry, and, because of its stipitate glands, in section Alleghenienses.

Davis et al. (1969b) suggested that it would belong to the R. alumnus L.H. Bailey complex if it is situated in the Alleghenienses. Among the currently recognized taxa in that section, it is true that the flaring inflorescences displayed by the type are typically found only in R. alumnus . But the size of its calyx lobes is smaller than those of R. alumnus , and its inflorescence length and hooked prickles also would be atypical for that species ( Widrlechner 2013). After an extensive search, we could find no other known member of the Alleghenienses that is a good match – only a few specimens resembling most of the characters presented in the R. floridus type.

Returning to the other option, some large, mounding species of Procumbentes produce side branches that get caught in vegetation and display determinate development and hooked prickles resembling those of the R. floridus type. Thus, we also conducted a search of the mounding, glandular Procumbentes. Of this group, the closest match is R. grimesii L.H. Bailey , a connection noted in passing by Bailey (1945) but never critically examined.

Figures

FIG. 11. — Rubus floridus Tratt. holotype, W(W0079959).