Contributed by Katherine Wagner-Reiss

The Morris Arboretum Catalogue of Plants in the Living Collection is an amazing online resource; many thanks to Elinor I. Goff, Plant Recorder. I count 530 Quercus   on the list, Quercus being the Latin name for the oak genus. Letʻs talk about those oaks at Morris Arboretum whose species names mention their color: Quercus alba (white oak), Quercus bicolor (swamp white oak), Quercus coccinea (scarlet oak), Quercus nigra (water oak), and Quercus rubra (northern red oak).

Quercus alba (white oak) with whitish bark. Photo by Katherine Wagner-Reiss.

Alba means white and Quercus alba is named for its whitish bark. It is the state tree of three states: Connecticut, Illinois, and Maryland (second only to the sugar maple, which is the state tree of four states)!


Quercus bicolor (swamp white oak) with two-toned bark. Photo by Katherine Wagner-Reiss.

Bicolor means two-colored and the bark on the branches of Quercus bicolor exfoliates so that the lighter inner bark is exposed, thus the specific epithet “bicolor.” It is the only oak with this feature. The common name “swamp white oak” gives additional useful information that this tree is found in swampy habitats.


Quercus coccinea with scarlet fall leaves. Photo by Famartin on Wikimedia Commons.

Coccinea means scarlet, and, while the leaves are green in the summer, the tree is named for its scarlet autumn leaves. It is the state tree of Washington, D.C.


Quercus nigra with blackish acorns. Photo by Robert H. Mohlenbrock, hosted by the USDA-NRCS PLANTS Database/USDA SCS.1991.

Nigra means black because the acorns of Quercus nigra are blackish or very dark.  The fallen acorns can stain concrete for months in the fall and winter. The common name  “water oak “ reveals that this is a bottomland tree, often found along streams.


Quercus rubra with red heartwood. Photo used with the permission of Dr.Elisabeth Wheeler of NC State University.

Rubra means red and Quercus rubra is named for its red heartwood. It is the state tree of New Jersey.

All of these color features are easily seen in the autumn, so I encourage you to look for them.

And now for a mind-teaser: What is the meaning of the capital of New Mexico?

Yes, Albuquerque means white oak!


Katherine has her Certificate in Botany from the New York Botanical Garden and is a botanical tour guide and free-lance writer.

Birtan Collier of WRDV (a non-commercial, educational, public radio station)  joined Morris Arboretum’s Executive Director, Paul Meyer for a tour of the Arboretum. Listen here to their conversation as they discuss Morris Arboretum’s history and its current priorities in today’s world which include historic preservation, plant exploration and research, sustainability, and youth education.



Tony Aiello, Director of Horticulture at the Morris Arboretum, reports that we can expect peak fall foliage in the greater Philadelphia region “in the third week of October through the end of the month, with some species like Japanese maples into early November”. Thanks to the mild summer temperatures and a relatively wet September, most plants are well hydrated and not losing their leaves due to drought. This year however, because of the very wet summer, some species like crabapples and cherries experienced fungal problems which led to early leaf drop.

 To see the brightest and best reds and oranges on this year’s trees, “hope for nice bright sunny days going from late September into October,” Aiello said. “We still need those sunny days.” 


Liquidambar styraciflua ‘Variegata’ Photo by Katherine Wagner-Reiss

Liquidambar formosana Photo by Katherine Wagner-Reiss


Article and photos contributed by Katherine Wagner-Reiss

Plant names can be just as interesting as the plants themselves, in my opinion! One of my favorite tree names is Liquidambar styraciflua , commonly called the American sweetgum tree.The genus Liquidambar and the species Liquidambar styraciflua were both officially named by Linnaeus , the father of modern taxonomy.

You don’t have to be a Latin scholar to interpret the species name as “liquid-amber storax- flowing.” Storax means gum resin, and is a word derived from the Greek word styrax .

The resin can be collected and used as chewing gum; I have read that it is not truly sweet; it is simply sweeter than the resin of Nyssa sylvatica , the native sour gum tree, which often grows in the same range.

The Plant Catalogue of the Morris Arboretum lists eight Liquidambar styraciflua. Two of these are cultivars: ‘Festival,’ named for the particularly festive fall leaf colors in tones of gold, orange, pinks and reds and ‘Variegata’, featuring green and yellow variegated leaves all summer turning to variegated pink and scarlet in the fall.

In addition to the native American sweetgum, the Arboretum also boasts a Liquidambar formosana (Formosa was the old name for Taiwan), and a Chinese Liquidambar acalycina (acalycina means without a calyx). The native L. styraciflua has star-shaped leaves with 5-7 lobes, while the non- native L. formosana and L. acalycina have only 3 lobes. Sweetgums vie with the maples for best fall color in the Northeastern US; yellow, orange, red, and purple leaves can decorate the same tree. Enjoy them all!


Katherine has her Certificate in Botany from the New York Botanical Garden and is a botanical tour guide and free-lance writer.