Philadelphus microphyllus |
Philadelphus coronarius |
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little leaf mock orange, small-leaf mock orange |
seringa commun, sweet mock-orange |
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Habit | Shrubs, 5–12(–20) dm. | Shrubs, 10–40 dm. | ||||||||||||||||||||
Stems | copper to reddish brown, stiffly to loosely branched, appressed villous-sericeous, ± strigose, hairs often red-gland based, or glabrous; epidermis soon or tardily deciduous exposing cortex and striate bundle caps; bark grayish; internodes (0.1–)1–2.5(–6) cm; short-shoot spurs not present; axillary buds hidden in pouches. |
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. |
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Leaves | petiole 1–2(–4) mm; blade greenish or whitish abaxially, green adaxially, linear-lanceolate, narrowly ovate to ovate, (0.5–)0.8–3(–5.5) × (0.2–)0.3–1.3(–3.3) cm, herbaceous to coriaceous, margins usually entire, rarely sparsely serrulate, plane or revolute upon drying, abaxial surface short sericeous-strigose, or sericeous-villous with longer hairs, or with ascending to erect hairs, sometimes with dense to moderate understory of slender curled hairs, adaxial surface glabrous, glabrate, ± sericeous-strigose, villous, or with erect hairs. |
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. |
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Inflorescences | usually solitary flowers, sometimes 3–5-flowered cymes. |
cymose racemes, 5–7(–9)-flowered, proximal 2 flowers often in axils of nearly normal to much reduced (bracteal) leaves. |
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Pedicels | 0.5–3 mm. |
3–20 mm, glabrous or sparsely strigose. |
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Flowers | hypanthium glabrous, sericeous-strigose basally or throughout, or weakly to densely villous to densely lanate with mixed strigose and villous vestiture, with understory of slender curled hairs; sepals ovate to lanceolate, (2.5–)4–8.5(–10) × (2.5–)3–4.3(–5) mm, apex acute to acuminate-caudate, abaxial surface glabrous, sericeous-strigose, or weakly to densely villous to densely lanate with mixed strigose and villous vestiture, with understory of slender curled hairs, adaxial surface glabrous except villous along distal margins; petals white [marked purple near base], oblong-obovate to broadly ovate, (5.8–)7–16(–21) × (5.3–)6–11(–15) mm, margins entire or erose-undulate, apex ± acute, rounded, or notched; stamens 26–64; filaments often connivent-connate in irregular clusters in proximal 0.5–4 mm, 1.8–8 mm, of unequal length, glabrous; anthers yellowish, 0.7–1.2 mm; styles 4, connate proximally, cylindric, 2.5–5.5(–7) mm, lobes sometimes connate proximally in pairs, 0.5–2.5 mm; stigmatic surfaces extending from adaxial lobes onto abaxial lobes and down to cylindric style. |
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. |
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Capsules | oblong-globose or globose-turbinate, (3.6–)5–8(–9.5) × (3.5–)4–7(–9.5) mm, sepals persisting at equator or more distally, capsule distal surface often impressed in 4(–8) radiating lines. |
obconic to obovoid, 7–11 × 4–7 mm. |
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Seeds | short caudate distally, 1.5–2.5 mm. |
caudate, 3 mm. |
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2n | = 26. |
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Philadelphus microphyllus |
Philadelphus coronarius |
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Phenology | Flowering May–Jul; fruiting Jul–Sep. | |||||||||||||||||||||
Habitat | Old home sites, suburban woodlands, stream banks. | |||||||||||||||||||||
Elevation | 0–1000 m. (0–3300 ft.) | |||||||||||||||||||||
Distribution |
AZ; CA; CO; NM; NV; TX; UT; WY; Mexico
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CT; GA; IL; IN; KS; MA; MD; ME; MI; MN; MO; NC; NH; NJ; NY; OH; PA; RI; SC; VA; VT; WI; NB; ON; QC; Eurasia [Introduced in North America]
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Discussion | Varieties 5 (4 in the flora). Within Philadelphus microphyllus as treated here, P. A. Rydberg (1905) recognized nine species, C. L. Hitchcock (1943) one species with eight subspecies, and Hu S. Y. (1954–1956) 11 species and four varieties, based on vestiture, leaf size and shape, and floral differences. Four varieties are recognized here within the flora area, with a fifth restricted to Mexico and without the needed varietal combination. Two characters are particularly important in distinguishing the varieties of Philadelphus microphyllus: adaxial leaf blade cuticle thickness and vestiture. Adaxial leaf blade cuticles can be thin and papillate, closely reflecting the adaxial epidermis cells (as seen at 30–40\x) or can be thick and smooth. Leaves with thin cuticles dry brown due to brownish granules developing in the epidermis; those with thick cuticles dry gray-green, olive green, or yellowish green without granules in the epidermis cells. Sometimes both types occur in a leaf in either a tight or bold mosaic pattern or the leaf blade may be papillate and brown only along its margins. Vestiture is mostly sericeous-strigose on leaves, stems, hypanthia, and sepals. The appressed hairs can be slender, short or long (0.2–1.5 mm), appressed, loosely appressed, ascending, or erect. The larger hairs have slender bases that allow them to be strictly appressed, but in some taxa, the base (upon drying) lifts and twists the hair upward, leaving the hairs oriented in many different directions; we refer to this condition as chaotic vestiture. In more densely vestitured plants, very slender, elongate, wavy-curved hairs form an understory beneath the more or less dense sericeous-strigose vestiture. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
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Key |
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Source | FNA vol. 12, p. 479. | FNA vol. 12, p. 484. | ||||||||||||||||||||
Parent taxa | Hydrangeaceae > Philadelphus | Hydrangeaceae > Philadelphus | ||||||||||||||||||||
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Synonyms | P. caucasicus | |||||||||||||||||||||
Name authority | A. Gray: Mem. Amer. Acad. Arts, n. s. 4: 54. (1849) | Linnaeus: Sp. Pl. 1: 470. (1753) | ||||||||||||||||||||
Web links |