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Alnus serrulata

(Alder)

Overview

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Interesting Facts

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Common Names

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Common Names in English:

Alder, Brook-Side Alder, Common Alder, Hazel Alder, Smooth Alder, Swamp Alder, Tag Alder

Description

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Family Betulaceae

Trees or shrubs deciduous, monoecious. Stipules present, free , often deciduous, rarely persistent . Leaves alternate, simple , petiolate , usually doubly serrate, rarely simply serrate, lobulate , or entire; veins pinnate. Flowers unisexual . Male inflorescence precocious , elongate , pendulous, with numerous overlapping bracts; each bract usually subtending a small dichasium with 1-3 male flowers; stamens as many as and opposite sepals or, if sepals obsolete , then stamens of inflorescence to 20; filaments very short, connate or nearly so; anthers 2-loculed, thecae connate or separate, opening by longitudinal slits. Female inflorescence pendulous or erect , with numerous overlapping bracts; each bract subtending a small dichasium with 2 or 3 flowers; calyx with 1-6 scalelike lobes , or obsolete; petals absent; ovary inferior, 2-loculed; styles 2, free; ovules 2, or 1 by abortion , pendulous from near apex of each locule. Fruit a nut or nutlet , winged or not. Seed 1, with straight embryo and flat or thickened cotyledons, without endosperm.

Six genera and 150-200 species: mainly in Asia, Europe, and North and South America; six genera (one endemic) and 89 species (56 endemic) in China.

Because of evolutionary divergence within the Betulaceae, the family has often been divided into tribes (i.e. , Betuleae, Carpineae, and Coryleae) or more recently into subfamilies (J. J. Furlow, J. Arnold Arbor . 71: 1-67. 1990) .[1]

Genus Alnus

Trees or shrubs , to 35 m ; trunks usually several, branching excurrent to deliquescent. Bark of trunks and branches light gray to dark brown, thin, smooth , close; lenticels often present, pale , prominent , sometimes horizontally expanded. Wood nearly white, turning reddish upon exposure to air , moderately light and soft, texture fine. Branches, branchlets , and twigs nearly 2-ranked to diffuse ; young twigs uniform or ( Alnus subg. Alnobetula ) differentiated into long and short shoots . Winter buds stipitate (nearly sessile in Alnus subg. Alnobetula ), narrowly to broadly ovoid or ellipsoid , terete , apex acute to rounded ; scales 2--3, valvate , or ( Alnus subg. Alnobetula ) several, imbricate, smooth, or ( Alnus subg. Clethropsis ) sometimes none. Leaves borne on long or short shoots, 3-ranked to nearly 2-ranked. Leaf blade ovate to elliptic or obovate , thin to leathery, base variable, cuneate to rounded, margins doubly serrate, serrate, serrulate , or nearly entire, apex variable, acute to obtuse or acuminate to rounded; surfaces glabrous to tomentose , abaxially sometimes resinous-glandular. Inflorescences: staminate catkins lateral , in racemose clusters or ( Alnus subg. Clethropsis ) solitary, formed ( Alnus subg. Alnus and Clethropsis ) during previous growing season and exposed or enclosed in buds during winter, or ( Alnus subg. Clethropsis ) formed and expanding during same growing season, expanding before or with leaves; pistillate catkins proximal to staminate catkins, solitary or in relatively small racemose clusters, erect to nearly pendulous, ovoid to ellipsoid, firm; scales and flowers crowded, developing and maturing at same time as staminate catkins. Staminate flowers in catkins, 3 per scale; stamens (3--) 4(--6) ; anthers and filaments undivided. Pistillate flowers usually 2 per scale. Infructescences erect or pendulous; scales persistent long after release of fruits, with 5 lobes , greatly thickened, woody. Fruits tiny samaras, lateral wings 2, leathery or membranaceous , reduced or essentially absent in some species. x = 7.

Species ca. 25 (8 sp: forested temperate and boreal Northern Hemisphere; North America; Asia.

Alders resemble birches but are easily distinguished from them by the infructescences, which consist of persistent , 5-lobed, woody scales (versus deciduous, 3-lobed, thin scales). Except in members of Alnus subg. Alnobetula Petermann (which have nearly sessile buds with several imbricate scales), alders are also distinctive in their stipitate buds bearing two stipular scales. The fruits, borne two to a scale, are laterally winged , although the wings are sometimes reduced or absent.

The genus is diverse , including several very distinct lines of specialization. The shrubby or arborescent Alnus subg. Alnus is characterized by winter buds with long stalks and two valvate scales, inflorescences borne in racemose clusters, and development of both pistillate and staminate inflorescences during the growing season prior to anthesis , with these fully exposed during winter. It includes the common A. rubra, A. incana, A. oblongifolia, and A. serrulata. Alnus subg. Alnobetula (represented in North America by three subspecies of A. viridis ) consists of shrubby species of cold-climate regions. In this group, the buds are nearly sessile and covered by several imbricate scales. Both staminate and pistillate catkins are formed the season before anthesis, but only the staminate ones are exposed during winter. The predominantly Asian Alnus subg. Clethropsis (Spach) Regel is represented in America by a single species, A. maritima, a small tree or large shrub of stream banks, marshes, and the shores of shallow lakes . Members of this group are unique in that they bloom in autumn rather than spring . They also differ from other native species in Alnus in having essentially naked buds, leaves with semicraspedodromous venation (i.e. , with the secondary veins branching and anastomosing with each other near the margin before reaching the teeth), and solitary pistillate inflorescences borne in the axils of foliage leaves. All of the alders associate symbiotically with species of the actinomycete Frankia, leading to the formation of nodules on the roots of the plants and the fixation of atmospheric nitrogen.[2]

Physical Description

Species Alnus serrulata

Shrubs , open to rather densely ascending , to 10 m. Bark light gray, smooth ; lenticels small, inconspicuous. Winter buds stipitate , ellipsoid to obovoid , 3--6 mm, apex mostly rounded ; stalks 2--4 mm; scales 2, equal, valvate , moderately to heavily resin-coated. Leaf blade broadly elliptic to obovate , 5--14 × 3.5--8 cm, leathery, base broadly to narrowly cuneate, margins flat, serrulate , without noticeably larger secondary teeth, apex obtuse to rounded; surfaces abaxially glabrous to moderately villous , slightly to moderately resin-coated. Inflorescences formed season before flowering and exposed during winter; staminate catkins in 1 or more clusters of 2--5, 3--8.5 cm, stamens 4; pistillate catkins in 1 or more clusters of 3--5. Flowering before new growth in spring . Infructescences ovoid-ellipsoid, 1--2.2 × 0.6--1.2 cm; peduncles 1--3(--5) mm. Samaras obovate, wings narrower than body, irregularly elliptic or obovate, leathery. 2 n = 28. Flowering early spring. [source]

Primarily an Atlantic coastal species, Alnus serrulata also grows along the St . Lawrence river system and the lower Great Lakes westward to the dunes of southern Lake Michigan, and across the southern states to the Gulf Coast and east Texas. Alnus serrulata was erroneously called A. rugosa in a number of earlier floristic works (J. K . Small 1903, 1933; N. L. Britton and A. Brown 1896, 1913; and B . L. Robinson and M. L. Fernald 1908), and the mistake was perpetuated in both editions of Flora Europaea (T. G. Tutin et al. 1964--1980, vol. 1; 1993+, vol. 1). [source]

Alnus incana subsp. rugosa hybridizes with A. serrulata (= Alnus serrulata var. subelliptica Fernald). Extensive hybrid swarms occur where the ranges of these species overlap, including the area along the St. Lawrence River and the southern edge of the Great Lakes (F. L. Steele 1961). R. H. Woodworth's conclusion (1929, 1930) that apomixis occurs in A. serrulata resulted from his use of material selected from a hybrid swarm. The remainder of the species appears to reproduce normally. The two species and their hybrids are usually easily distinguished by leaf shape and margin characters. [source]

Habit: Tree , ShrubGrowth Form: Multiple StemShape and Orientation: Erect

Flowers: Bloom Period: SpringFlower Color: inconspicuous, none • Flower Conspicuous: No

Seeds: Seed per Pound: 400000 • Seed Spread Rate: Moderate • Seedling Vigor: Low • Fruit/Seed Abundance: Low • Fruit/Seed Color: Brown • Fruit/Seed Conspicuous: No • Cold Stratification Required: Yes

Foliage: Foliage Color: Green • Foliage Porosity Summer: Dense • Foliage Porosity Winter: Porous • Foliage Texture: CoarseFall Conspicuous: No • Leaf Retention: No

Size/Age/Growth

Active Growth Period: Spring and Summer • Growth Rate: Rapid • Mature Height (feet): 30.0 • Maximum Height at 20 Years (feet): 12 • Size: 6-8' tall. • Vegetative Spread Rate: Slow • Lifespan: Lifespan

Habitat

Stream banks, ditches, edges of sloughs , swampy fields and bogs , and lakeshores; 0--800 m [3].

Typically found at an altitude of 0 to 1,092 meters (0 to 3,583 feet).[4]

Biology

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Reproduction

Duration: PerennialCoppice Potential: No • Progagated by Bulbs: No • Propagated by Bare Root: Yes • Propagated by Container: Yes • Propagated by Corms: No • Propagated by Cuttings: No • Propagated by Seed: Yes • Propagated by Sod: No • Propagated by Sprigs: No • Propagated by Tubers: No • Fruit/Seed Period Begin: Summer • Fruit/Seed Period End: Summer • Fruit/Seed Persistence: No

Growth

Culture: Space 12-15' apart.

Soil: Adapted to Medium Textured: Adapted to Medium Textured Soils • Adapted to Coarse Textured Soils: Yes • Anaerobic Tolerance: High • Salinity Tolerance: None • CaCO3 Tolerance: Low • Minimum pH: 5.0 • Maximum pH: 7.0 • Fertility Requirement: Medium

Sunlight: Sun Exposure: Full Sun . • Shade Tolerance: Intolerant

Moisture: Drought Tolerance: Low • Minimum Precipitation: 32 • Maximum Precipitation: 60 • Moisture Use: High

Temperature: Minimum Temperature (F): -23 • Minimum Frost Free Days: 120 • Cold Hardiness: 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b. (map)

Taxonomy

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Synonyms

A. rubra Desfontaines Ex Spach • A. rugosa (Du Roi) Sprengel Var. serrulata (Aiton) Winkler • Alnus americana K. Koch • Alnus autumnalis Hartig Ex Garcke • Alnus glutinosa obtusifolia Regel • Alnus glutinosa var. autumnalis Kuntze • Alnus glutinosa var. serrulata (Aiton) Regel • Alnus incana var. serrulata (Aiton) Boivin • Alnus latifolia Desf. • Alnus macrophylla Desf. Ex Steud. • Alnus noveboracensis Britton • Alnus oblongata (Aiton) Willd. • Alnus obtusifolia Mert. Ex Regel • Alnus rubra Desf. Ex Steud. • Alnus rugosa (Du Roi) Spreng. Var. serrulata (Aiton) H. Winkl. • Alnus rugosa Regel • Alnus rugosa var. obtusifolia (Regel) H. Winkl. • Alnus rugosa var. serrulata (Aiton) H. Winkl. • Alnus serrulata f. emarginata Fernald • Alnus serrulata f. mollescens Fernald • Alnus serrulata f. nanella Fernald • Alnus serrulata f. noveboracensis (Britton) Fernald • Alnus serrulata var. macrophylla Spach • Alnus serrulata var. obtusifolia (Regel) Regel • Alnus serrulata var. subelliptica Fernald • Alnus serrulata var. vulgaris Fernald • Betula Alnus Serrulata • Betula alnus var. serrulata (Aiton) Michx. • Betula oblongata Aiton • Betula serrulata Aiton • Hort. Kew. 1: 338. 1789

Notes

Publishing author : Willd. Publication : Sp. Pl., ed. 4 [Willdenow] 4(1): 336 1805

Name Status: Accepted Name .

Last scrutiny: 11-Nov-2003

Similar Species

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Members of the genus Alnus

ZipcodeZoo has pages for 28 species, subspecies, varieties, forms, and cultivars in this genus:

A. acuminata (Alder) · A. acuminata glabrata (Mexican Alder) · A. cordata (Italian Alder) · A. fallacina (Alder) · A. glutinosa (Black Alder) · A. glutinosa glutinosa (European Black Alder) · A. glutinosa 'Imperialis' (Black Alder) · A. glutinosa 'Pyramidalis' (Black Alder) · A. hirsuta (Manchurian Alder) · A. incana (Gray Alder) · A. incana incana (Speckled Alder) · A. incana rugosa (Gray Alder) · A. incana tenuifolia (Gray Alder) · A. japonica (Japanese Alder) · A. maritima (Seaside Alder) · A. nepalensis (Indian Alder) · A. nitida (West Himalayan Alder) · A. oblongifolia (Arizona Alder) · A. rhombifolia (Alder) · A. rubra (Oregon Alder) · A. rubra f. pinnatisecta (Oregon Alder) · A. serrulata (Alder) · A. viridis (Green Alder) · A. viridis crispa (Green Alder) · A. viridis fruticosa (Green Alder) · A. viridis sinuata (Green Alder) · A. viridis viridis (European Green Alder) · A. x fallacina (Alder)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal November 15, 2007:

Identifiers

Footnotes

  1. Pei-chun Li & Alexei K. Skvortsov "Betulaceae". in Flora of China Vol. 4 Page 286. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org. [back]
  2. "Alnus". in Flora of North America Vol. 3. Oxford University Press. Online at EFloras.org. [back]
  3. "Alnus serrulata". in Flora of North America Vol. 3. Oxford University Press. Online at EFloras.org. [back]
  4. Mean = 211.840 meters (695.013 feet), Standard Deviation = 197.850 based on 1,101 observations. Altitude information for each observation from British Oceanographic Data Centre. [back]
Last Revised: 7/15/2012