Collection Statistics

Permanent Collections

As of September 2024, the permanent collections (which exclude nursery holdings) comprise 16,195 individual plants that belong to 10,471 accessions. These accessions represent 2,147 different species and 1,458 cultivars, which respectively illustrate the Arboretum’s broad biological and horticultural diversity, exceptional for a temperate woody plant collection.

The collections are considered one of the best documented in the world, especially with regard to wild provenance. Many of these lineages are of historical and botanical importance, representing the original North American introductions of eastern Asian plants collected by Arboretum staff such as Charles Sprague Sargent, Ernest H. Wilson, John G. Jack, Joseph Rock, and William Purdom.

Contemporary explorers continue a legacy of plant discovery now guided by the Campaign for the Living Collections.

Read more about the over 150 years’ of plant exploration at the Arnold Arboretum.

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Table 1. Taxonomic profile of the Living Collections (Includes Nursery Holdings) of the Arnold Arboretum.^a

RANK	NUMBER
Families	124
Genera	446
Species	2,240
Subspecies	111
Varieties	319
Formae	60
Cultivars	1,479
Interspecific Hybrids	432
Intergeneric Hybrids	14

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Table 2. Provenance of Accessions in the Living Collections (Includes Nursery Holdings) of the Arnold Arboretum.

PROVENANCE	TOTAL NUMBER	PERCENT OF TOTAL
Wild
Direct	3,277	30
Indirecta	979	9
Garden	3,079	27
Uncertainb	3,637	34

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Dead Collections

Only a minority of the accessions ever attempted to be grown in the collections of the Arnold Arboretum are currently alive—some perished on the grounds, while others representing propagules (e.g., seed, graft, cutting) may have never grown to maturity. The records associated with these legacy collections hold immense value in documenting the history of plant introductions, since the Arboretum facilitated the initial point of entry in North America for many species.

As of June 2024, the legacy collections comprised 105,607 accessions representing 23,254 taxa (kinds). Of these, 69,994 individual plants belonging to 46,312 accessions representing 13,574 taxa (kinds) were inventoried within the living collections (which include nursery holdings) before perishing.

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Table 3. Taxonomic profile of the Legacy (Dead) Collections of the Arnold Arboretum.^a

RANK	NUMBER
Families	271
Genera	1,699
Species	12,681
Subspecies	337
Varieties	1,714
Formae	316
Cultivars	9,232
Interspecific Hybrids	1,707
Intergeneric Hybrids	106

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Table 4. Provenance of the Legacy (Dead) Accessions of the Arnold Arboretum.

PROVENANCE	TOTAL NUMBER	PERCENT OF TOTAL
Wild
Direct	18,875	18
Indirecta	5,823	6
Garden	34,673	32
Uncertainb	46,236	44