The World Flora Online

Shrubs. Stems erect, ascending, arching, or spreading, decussately branched. Bark tight or exfoliating in grayish, brown, or reddish brown sheets. Branches erect, ascending, or spreading, often arching; twigs glabrous or with simple trichomes. Leaves winter- or drought-deciduous, opposite; petiole present; blade ovate, elliptic-ovate, elliptic, suborbiculate, lanceolate, or linear-lanceolate, herbaceous, subcoriaceous, or coriaceous, margins entire or serrulate to serrate, often irregularly and variably so, plane or revolute; venation acrodromous, secondarily and distally pinnate. Inflorescences terminal, sometimes appearing axillary when 1-flowered, cymes, cymose racemes, or cymose panicles, or flowers solitary, 1–49-flowered; peduncle present. Pedicels present. Flowers bisexual; perianth and androecium perigynous to epigynous; hypanthium completely adnate to ovary, turbinate, obconic, or hemispheric, weakly or strongly 4- or 8-ribbed in fruit; sepals usually persistent, 4, spreading or reflexed, deltate to triangular-acuminate, villous, strigose, or glabrous; petals 4 (or 8+ in some horticultural forms), imbricate, spreading to ascending, white to cream colored, rarely purple-maculate, drying yellowish, oblong-obovate, obovate, or orbiculate, base sessile and tapered, or minutely clawed, surfaces glabrous [rarely hairy]; stamens (11–)13–90; filaments distinct or irregularly connate into groups proximally, dorsiventrally flattened proximally, gradually or abruptly tapered from base to apex, apex not 2-lobed, although sometimes slightly notched; anthers depressed-ovate or transversely oblong; pistil 4-carpellate, ovary inferior to 1/2 inferior, 4-locular; placentation axile proximally, parietal distally; styles persistent, 1 or 4, connate proximally to completely; stigmas 4. Capsules turbinate, obconic to obovoid, hemispheric, subglobose, or oblong-ovoid, coriaceous, persistent and gradually deteriorating, dehiscence loculicidal. Seeds 10+ per locule, rusty brown, fusiform, sometimes caudate. x = 13.

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Shrubs erect, rarely climbing, rarely spinescent. Branchlets opposite. Leaves opposite, exstipulate, veins 3-5, basifugal, margin entire or serrate. Inflorescences racemose, paniculate, or cymose, rarely 1-flowered. Flowers fragrant. Calyx tube campanulate or turbinate, adnate to ovary; lobes 4(or 5). Petals 4(or 5), white, contorted. Stamens 13-90; filaments flat, free or basally connate; anthers ovoid or oblong, rarely globose. Ovary inferior or subinferior, 4(or 5)-loculed; placentation axile; ovules numerous, pendulous. Style (3 or)4(or 5)-lobed; stigmas clavate or spatulate. Fruit a capsule, 4(or 5)-valved, dehiscing by valves; epicarp papery; endocarp corky. Seeds numerous.

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Deciduous shrubs with slender, arching and occasionally scandent stems with close or sometimes flaking bark. Leaves opposite, entire or dentate, sessile or shortly petiolate, lower surface often pubescent with simple hairs, upper surface green and glabrous or with few scattered pili, usually with 3-5 prominent veins from base. Flowers white, showy, often fragrant, solitary or in few-flowered terminal cymes; hypanthium turbinate, united with the ovary, calyx-lobes 4, rarely 5-6; petals 4, rarely 5-6, obovate, rounded or retuse at apex, convolute in bud; stamens 20 or more, filaments flat, subulate, anthers small, oblong; ovary inferior to half superior, 4 or rarely 3 or 5 chambers, placentae axial, bearing numerous ovules; styles 3-5, filiform, more or less united, each bearing an elongate stigma; capsule turbinate, ligneous or coriaceous, 3-5 chambers, dehiscing loculicidally from the top; seeds numerous, oblong.

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shrubs

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About 40 species in North and Central America, eastern Asia and southern Europe.

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SELECTED REFERENCES Beadle, C. D. 1902. Studies in Philadelphus. Biltmore Bot. Stud. 1: 159–161. Frazier, C. K. 1999. A taxonomic study of Philadelphus (Hydrangeaceae) as it occurs in New Mexico. New Mexico Bot. Newslett. 13: 1–6. Hitchcock, C. L. 1943. The xerophyllous species of Philadelphus in southwestern North America. Madroño 7: 36–56. Hoffman, M. H. A. 1996. Cultivar classification of Philadelphus L. (Hydrangeaceae). Acta Bot. Neerl. 45: 199–209. Hu, S. Y. 1954–1956. A monograph of the genus Philadelphus. J. Arnold Arbor. 35: 275–333; 36: 52–109, 325–368; 37: 15–90. Rydberg, P. A. 1905. Philadelphus. In: N. L. Britton et al., eds. 1905+. North American Flora.... 47+ vols. New York. Vol. 22, pp. 162–175. Turner, B. L. 2006. Species of Philadelphus (Hydrangeaceae) from trans-Pecos Texas. Lundellia 9: 34–40. Weakley, A. E. 2002. Evolutionary Relationships within the Genus Philadelphus (Hydrangeaceae): A Molecular Phylogenetic and Biogeographic Analysis. M.A. thesis. University of North Carolina. Wright, D. 1980. Philadelphus. Plantsman 2: 104–116.

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