Collection Statistics

Permanent Collections

As of March 2023, the permanent collections (which exclude nursery holdings) comprise 16,006 individual plants that belong to 10,446 accessions. These accessions represent 2,111 different species and 1,396 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 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	115
Genera	417
Species	2,191
Subspecies	105
Varieties	334
Formae	61
Cultivars	1,406
Interspecific Hybrids	433
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	3,270	30
Indirecta	952	9
Garden	2,950	27
Uncertainb	3,742	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 January 2023, the legacy collections comprised 98,235 accessions representing 22,046 taxa (kinds). Of these, 69,224 individual plants belonging to 45,941 accessions representing 13,523 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	260
Genera	1,603
Species	12,117
Subspecies	331
Varieties	1,713
Formae	314
Cultivars	8,647
Interspecific Hybrids	1,689
Intergeneric Hybrids	102

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

PROVENANCE	TOTAL NUMBER	PERCENT OF TOTAL
Wild
Direct	18,190	18
Indirecta	5,519	6
Garden	31,574	32
Uncertainb	42,952	44