Alnus dolichocarpa Zare, Amini & Assadi

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Credits

Tim Baxter & Hugh A. McAllister (2024)

Recommended citation
Baxter, T. & McAllister, H.A. (2024), 'Alnus dolichocarpa ' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/alnus/alnus-dolichocarpa/). Accessed 2024-04-11.

Genus

Glossary

acuminate
Narrowing gradually to a point.
caudate
With a long tail-like appendage.
hybrid
Plant originating from the cross-fertilisation of genetically distinct individuals (e.g. two species or two subspecies).
reticulate
Arranged in a net-like manner.
taxonomy
Classification usually in a biological sense.

Credits

Tim Baxter & Hugh A. McAllister (2024)

Recommended citation
Baxter, T. & McAllister, H.A. (2024), 'Alnus dolichocarpa ' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/alnus/alnus-dolichocarpa/). Accessed 2024-04-11.

Tree to 25 m. Bark dark grey, grooved. Twigs angled, triangular, greyish with short hairs. Buds with short stalk, pubescent. Leaves ovate, elliptic to suborbicular, slightly oblique, 9–16 × 5–10 cm, base cordate, apex abruptly acuminate (long acuminate) or caudate, upper half with large triangular teeth, basal half serrate to undulate, blade glabrous, veins occasionally sparsely pubescent, hairy domatia, craspidodromous venation, 7–8 veins either side of midrib, straight, prominent, reddish brown. Petioles 2–3 cm, puberulent, reddish at first. Staminode catkins catkins 1–4, 25–40 mm long, thin. Pistillate catkins red with relatively long peduncle. Fruit woody, cone-like, ovate-elliptic, 30–40 × 10–20 mm, bracts 4–6 large teeth, with spiral shape spread toward the apex. Seeds elliptic-obovate, asymmetric and often prominent in one side, wings leathery and narrow, complete around the seed. Flowering March to April; fruit ripening November. (Zare & Amini 2012).

Distribution  Iran

Habitat Wet soils in Hyrcanian Forests with good drainage often alongside Alnus subcordata and Fagus orientalis.

Conservation status Critically endangered (CR)

Alnus dolichocarpa is a recently described (2012) species from northern Iran (Zare & Amini 2012). It is clearly closely related to A. glutinosa and A. subcordata; it is most easily distinguished by the leaves coarsely toothed in the apical half only, acuminate to caudate leaf apices, large cones with prominent ligule on the scale, and asymmetrical seed. A. dolichocarpa is a relatively rare species, restricted to the Hyrcanian Forests of northern Iran in upland regions.

There is evidence for gene flow between several species in the Turco-Iranian region, and as is the case with the putative species A. djavanshirii it is uncertain if A. dolichocarpa is worthy of separation to species level; it may just be a distinct local form or hybrid. It clearly belongs to a species complex in the Hyrcanian forests alongside A. subcordata, A. djavanshirii, 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 taxonomy of A. dolichocarpa remains uncertain.

It is not known in cultivation outside of Iran althouth it may have some potential as a drought tolerant tree of large stature. It is unclear if plants introduced as Alnus subcordata ‘Oberon’ actually represent A. dolichocarpa; certainly they appear to match the description of the species (T. Baxter pers. obs.).