Fallopia scandens
Fallopia dumetorum
climbing bindweed, climbing false-buckwheat
climbing false buckwheat, copse-bindweed, renouée des haies, thicket bindweed
ocrea usually deciduous, tan or brown, cylindric to funnelform, 1–6 mm, margins oblique, face not fringed with reflexed hairs and slender bristles at base, otherwise glabrous or scabrid;
petiole 0.5–10 cm, glabrous or scabrid in lines;
blade cordate, truncate-deltate, or hastate, 2–14 × 2–7 cm, base cordate, margins wavy, scabrid, apex acuminate, abaxially and adaxially faces glabrous or papillose to scabrid, not glaucous, the abaxial rarely minutely dotted.
ocrea usually deciduous, tan or brown, cylindric to funnelform, 1.5–3.5 mm, margins oblique, face not fringed with reflexed hairs and slender bristles at base, otherwise glabrous or scabrid;
petiole 0.3–2.5 cm, glabrous or scabrid in lines;
blade triangular to hastate, 2–8 × 1–5 cm, base cordate to truncate, margins wavy, scabrid, apex acute to acuminate, abaxially and adaxially faces glabrous or papillose to scabrid, not glaucous, the abaxial rarely minutely dotted.
axillary, erect or spreading, racemelike, 1–28 cm, axes scabrid;
peduncle 0.1–7 cm or absent, scabrid.
axillary, erect or spreading, racemelike, 2–20 cm, axes glabrous or scabrid;
peduncle 0.1–6 cm or absent, glabrous or scabrid.
ascending or spreading to reflexed, articulated distally, 4–8 mm, glabrous.
ascending or spreading to deflexed, articulated distally, 4–8 mm, glabrous.
bisexual, 3–6 per ocreate fascicle;
perianth accrescent in fruit, green to white or pinkish, 3.8–8 mm including stipelike base, glabrous;
tepals elliptic to obovate, apex obtuse to acute, outer 3 winged;
stamens 8;
filaments flattened proximally, pubescent proximally;
styles connate;
stigmas capitate.
bisexual, 2–6 per ocreate fascicle;
perianth accrescent in fruit, greenish white or pinkish, 3.5–7 mm including stipelike base, glabrous;
tepals elliptic to obovate, apex obtuse to acute, outer 3 winged;
stamens 8;
filaments flattened proximally, pubescent proximally;
styles connate;
stigmas capitate.
included, dark brown to black, 2–6 × 1.4–3.5 mm, shiny, smooth; fruiting perianth glabrous, wings undulate or crinkled, rarely flat, (0.7–)1.5–2.1 mm wide, decurrent on stipelike base nearly to articulation, margins wavy-crenate to incised or lacerate, rarely entire.
included, black, 2–4 × 1.8–2.4 mm, shiny, smooth; fruiting perianth glabrous, wings flat or, less often, undulate or crinkled, 1.5–2 mm wide, usually truncate or attenuate-decurrent on stipelike base nearly to articulation, margins entire or rarely undulate-crenate.
= 20.
= 20.
Fallopia scandens
Fallopia dumetorum
Fallopia scandens has a complex nomenclatural history, which in North America usually involves three taxonomic elements: F. scandens and F. cristata, both native in North America, and F. dumetorum, which is native in Europe. Achene and perianth characters have been used to distinguish these elements, but variable and intergrading morphologies have caused taxonomists to combine them variously. Morphometric (S. T. Kim et al. 2000) and flavonoid (M. H. Kim et al. 2000) studies suggest that F. scandens and F. dumetorum are distinct species. Where F. scandens is absent, European specimens of F. dumetorum are distinctive. This distinction is far less clear in North America, where both species occur. Experience suggests that many North American herbarium specimens attributed to F. dumetorum are misidentified.
Fallopia cristata has been distinguished from F. scandens and F. dumetorum by its smaller fruiting perianths (5–7[–9] mm) bearing narrower (1.2–1.7 mm wide), undulate-crenate or lacerate wings, and smaller achenes (2.1–2.7 mm). Extreme forms are easily identified; some specimens grade gradually into F. scandens, making recognition of F. cristata of questionable utility. S. T. Kim et al. (2000) used morphometric studies as a basis for recommending that F. cristata is best treated as a variety of F. scandens.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Because of similarity to Fallopia scandens, specimens of F. dumetorum often are misidentified. Consequently, the range of F. dumetorum in North America is unclear; it is probably exaggerated in most floras.
Mature fruiting perianths provide the most reliable characters distinguishing Fallopia dumetorum from F. scandens. European specimens of F. dumetorum, have fruiting perianths that are consistently orbiculate in outline, with wings usually flat and abruptly contracted on the stipelike perianth bases. Fallopia scandens has fruiting perianths that are obovate in outline, with wings undulate and gradually decurrent on the stipelike perianth bases. Additional characteristics reported to distinguish F. dumetorum from F. scandens are its annual habit (F. scandens also is reported to be annual in some of the literature) and more triangular leaf blades with cordate or sagittate bases. In recognizing F. dumetorum, we follow S. T. Kim et al. (2000) and M. H. Kim et al. (2000), who concluded from limited morphological and flavonoid data that the taxa are best treated as distinct species. More detailed studies may prove the two to be conspecific.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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