The elm cultivar Ulmus Densa was described from specimens growing near Ashkabad as U. densa Litv. in Schedae ad Herbarium Florae Rossicae (1908).^[1] Litvinov, reporting it growing wild in the mountains of Turkestan, Ferghana, and Aksu, as well as in cultivation, considered it a species, a view upheld by the Soviet publications Trees and Shrubs in the USSR (1951)^[2] and Flora of Armenia (1962),^[3] and by some current plant lists.^{[4][5][note 1]} Other authorities take it to be a form of U minor, distinctive only in its dense crown and upright branching.^[6][7][8] The Moscow State University herbarium gives (2020) Ulmus minor as the "accepted name" of U. densa Litv..^[9][10]

Litvinov considered U. minor 'Umbraculifera', with its "denser crown and more rounded form", a cultivar of U. densa,^[6] calling it U. densa var. bubyriana. Rehder (1949) and Green (1964), ignoring reports of the wild form, considered U. densa a synonym of 'Umbraculifera'.^[11][12] The U. densa photographed by Meyer in Aksu, Chinese Turkestan on his 1911-12 expedition does not appear to be the tidy grafted cultivar 'Umbraculifera' and was said to be named 'Seda'.^[13][14] Zielińksi in Flora Iranica (1979) considered 'Umbraculifera' an U. minor cultivar.^[15]

In its natural range U. densa overlaps with U. pumila. The extent of hybridization between the two is not known.

Litvinov noted that the tree "differed little from U. glabra Mill." [:U. minor]^[16] except in its erect branches and dense oblong crown.^[17] The leaves were "generally smaller" ^[18] and the branches "smooth and lighter in colour". As with the hybrid U. × androssowii, its compact branch structure helps the tree conserve moisture.^[19]

Not known.

Litvinov said that U. densa was "widely cultivated" in gardens in Turkestan. It is one of a number of elms known locally as 'karagach' or 'karagatch' [:'black tree' = elm].^[20][21][22] In western Europe U. densa Litv. was distributed by Hesse's Nurseries, Weener, Germany, in the 1930s.^[23]

• Dense-branched elm, upright form, Turkestan, c.1900
• Dense-branched elm, spreading form, Turkestan, c.1900
• Dense-branched elm (left), Turkestan, c.1912
• Ulmus densa in Urumqi Botanical Garden, Xinjiang, China (2021)

A large, well-grown specimen stands in Dushanbe Botanic Gardens, Tajikistan (2019).^[24][25]

These include one of the oldest of elm cultivars, 'Umbraculifera', and a number of elms introduced to the West by the Späth nursery of Berlin.

• U. minor 'Umbraculifera', (?) U. minor 'Rueppellii', (?) U. 'Globosa', (?) U.' 'Koopmannii'

Meyer (1912) identified three cultivars of U. densa: 'Stamboul', 'Kitaisky' and 'Seda'.^[26][14]

The tree, or its cultivar form 'Umbraculifera', has hybridised with U. pumila to produce U. × androssowii.

None known.