Alnus djavanshirii Zare

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Credits

Tim Baxter & Hugh A. McAllister (2024)

Recommended citation
Baxter, T. & McAllister, H.A. (2024), 'Alnus djavanshirii' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/alnus/alnus-djavanshirii/). Accessed 2024-05-21.

Genus

  • Alnus
  • Subgen. Alnus, Sect. Japonicae

Glossary

asl
Above sea-level.
glabrous
Lacking hairs smooth. glabrescent Becoming hairless.
globose
globularSpherical or globe-shaped.
hybrid
Plant originating from the cross-fertilisation of genetically distinct individuals (e.g. two species or two subspecies).
ovate
Egg-shaped; broadest towards the stem.
reticulate
Arranged in a net-like manner.

Credits

Tim Baxter & Hugh A. McAllister (2024)

Recommended citation
Baxter, T. & McAllister, H.A. (2024), 'Alnus djavanshirii' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/alnus/alnus-djavanshirii/). Accessed 2024-05-21.

Tree to 20–30 m tall. Trunk light to dark grey, fissured. Branchlets olive-green to light grey, white pubescent, angular, with light brown, prominent, often transversal lenticels. Winter buds stipitate, pubescent, ovate, glutinous. Leaves elliptic (rarely ovate), twice as long as broad, 6–13 × 3–6 cm, apex broadly acute, rarely acuminate, base cuneate or attenuate, margin with minute serrulate toothing, mucronate, adaxially glabrous and olive-green to grayish, abaxially green-yellowish, glabrous except sparsely pubescent on veins and axillary tufts, veins yellow, often straight, 8(–10) either side of midrib, petiole pubescent, 2.5–4 cm. Staminode inflorescences in clusters of 1–6, peduncle short, pubescent, 30–45 × 5 mm. Fruit globose or broadly ovate, 1.2–2 × 1–1.8 mm, peduncle 6–8 mm. Seed narrowly oblong, glabrescent, 3–4 mm long, without wing, glossy and light brown. Flowering February to March, fruit ripening in October. (Zare & Amini 2012).

Distribution  Iran Dodangeh region, south of Sari

Habitat Mixed, open Carpinus betulus woodland on wet soils with rich humus layer, with Acer cappadocicum, A. velutinum, Zelkova carpinifolia, Crataegus spp. and Parrotia persica, at around 1000 m asl.

Conservation status Not evaluated (NE)

Alnus djavanshirii is a recently described (2012) species from northern Iran, described as very rare and restricted to the Dodangeh region, south of Sari, where it grows at an elevation of c. 1000 m asl in the mid-altitude zone of Iran’s Hyrcanian forests (Zare & Amini 2012). It is not known in cultivation but is likely to be a drought tolerant tree of moderate ornamental merit, similar perhaps to A. orientalis. It is distinguished from A. orientalis in having globose, not ovate fruit, and leaf margins minutely serrulate, not lobulate; from A. subcordata it differs in having more or less glabrous petioles and leaves.

There is evidence for gene flow between several species in the Turco-Iranian region, and it is uncertain if A. djavanshirii is worthy of distinction at species level; it may just be a distinct local form or even a hybrid. It clearly belongs to a species complex in the Hyrcanian forests alongside A. subcordata, A. dolichocarpa, A. orientalis and A. glutinosa s.l. (e.g. Colagar et al. 2016). The cytology of these species is rather confused, with A. subcordata, A. glutinosa and A. orientalis all polyploid species (Rice et al. 2015). The situation is likely, therefore, to be similar to that of A. glutinosa in southern Europe, having a reticulate evolutionary history, with species mixing and forming polyploids. Until material is compared to other taxa in a broader context there can be no resolution, and the validity of A. djavanshirii remains uncertain.