Alnus djavanshirii Zare

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.