Philadelphus coronarius
Philadelphus mearnsii
seringa commun, sweet mock-orange
Mearns' mock orange
erect to ascending, green, older stems brown, branched, glabrous or sparsely strigose (especially at nodes);
bark deciduous, exfoliating or flaking, reddish;
branches erect to arching;
axillary buds hidden in pouches, sometimes apex exposed, especially on vigorous sprout-shoots.
tan-brown, weathering gray, striate, stiffly divaricately branched, strigose-sericeous;
internodes 0.1–3.5 cm; short shoots often present;
axillary buds exposed.
petiole 1–6 mm;
blade usually broadly lanceolate to broadly ovate, or narrowly to broadly elliptic, rarely narrowly lanceolate in horticultural forms, 3–10 × 2–6 cm, larger blades usually greater than 6 × 2.5 cm, base narrowly cuneate to rounded, margins entire to irregularly or regularly serrate, crenate, or dentate, plane, abaxial surface glabrous or sparsely strigose, hairs usually appressed-ascending, not twisted, main vein axils often moderately to densely strigose-tomentose, main veins sometimes sparsely strigose, secondary and tertiary veins rarely sparsely strigose, adaxial surface glabrous or sparsely strigose, especially near base and margins.
petiole 0.5–4 mm;
blade green or gray-green abaxially and adaxially, oblong-lanceolate, linear-lanceolate, or elliptic to ovate, 0.5–1.7(–3) × 0.1–0.6(–1.1) cm, coriaceous, margins entire, ± revolute, surfaces ± equally moderately strigose, hairs appressed, coarse, 0.2–0.6(–0.9) mm, without understory of coiled-crisped hairs;
veins inconspicuous.
cymose racemes, 5–7(–9)-flowered, proximal 2 flowers often in axils of nearly normal to much reduced (bracteal) leaves.
flowers solitary, produced from previous year's long shoots, often appearing axillary.
3–20 mm, glabrous or sparsely strigose.
0.5–2 mm.
hypanthium glabrous or sparsely strigose to villous;
sepals ovate, ovate-lanceolate, or triangular, 4–8 × 2.5–5 mm, apex acute to acuminate, abaxial surface glabrous or sparsely strigose, adaxial surface glabrous except densely villosulous distally;
petals white to cream, oblong, obovate, or orbiculate, 5–25 × 5–22 mm;
stamens 20–50;
filaments distinct, 4–9 mm;
anthers 1–1.5 × 0.7–1 mm;
styles 4, connate proximally, cylindric, 7–10 mm, lobes 3–8 × 0.3–0.9 mm;
stigmatic surfaces 1–4 mm.
hypanthium sparsely to moderately strigose-sericeous or glabrous;
sepals ovate-lanceolate, 2–3.5(–4.2) × 1.3–2.3 mm, apex acute to acuminate-caudate, abaxial surface sparsely to moderately strigose-sericeous or glabrous, adaxial surface glabrous except villous along distal margins;
petals white, oblong-lanceolate to broadly oblong-ovate, (5–)7–8.5(–10) × 2.5–4.5(–5.8) mm;
stamens 13–18(–24);
filaments distinct, 1.3–4 mm;
style 1, clavate, 2–3.2 mm, narrow base 0.5–1.5 mm;
stigmatic portion 1.3–2 mm, distally lobed to 0.5 mm.
obconic to obovoid, 7–11 × 4–7 mm.
ovoid-turbinate, 3–5.5 × 3.2–5.5 mm, sepals ± persistent at distal 1/3 or more distally, capsule distal surface impressed in 4(–8) radial lines.
caudate, 3 mm.
not caudate, 1–1.2 mm.
= 26.
Philadelphus coronarius
Philadelphus mearnsii
Philadelphus coronarius is likely to occur in states and provinces other than those listed because it is widely cultivated and may escape.
Philadelphus caucasicus is here provisionally considered to be a synonym of P. coronarius, though further study in their native area is needed. Both are native in the Caucasus region, according to Hu S. Y. (1954–1956), and the only character by which she separated them (vestiture on the disc and style) is variable in other taxa in the genus and seems of doubtful taxonomic meaning in the case of these two sympatric, putative taxa. The native distribution of P. coronarius is unclear. Hu considered it native in southern Europe and the Caucasus Mountains of southern Russia, Armenia, Georgia, and Azerbaijan. D. A. Webb (1993) emphasized the uncertainty of its native range, mentioning that stations in Europe where it is undoubtedly native are very few; it may be that this species is native only in the Caucasus and was brought early to Europe for ornament.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Philadelphus hitchcockianus, with its hypanthium and abaxial sepal surfaces glabrous, is here synonymized with P. mearnsii, which has its hypanthium and abaxial sepal surfaces moderately sericeous-strigose; substantial variation in this character is found in several populations. Hu S. Y. (1954–1956) alleged that P. hitchcockianus and P. mearnsii also differ in fruit size; however, that character is variable and overlapping.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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