Of interest this week at Beal...

Stern’s Medlar canescens Family: the Rose family, No other names W. J. Beal Botanical Garden The very idea that one might discover an undescribed species of large woody na- tive to North America near the end of the twentieth century seems fanciful on its face. But Stern’s medlar is just such an improbable species. With the type material discov- ered by Jane Stern, this extremely showy flowering bush or small only the second species to be assigned to the genus Mespilus. The other species, , is the European medlar. It has been a known food plant for millennia and in some regions a known .

This species assignment to the genus Mespilus, even as recognized by its author James B. Phipps, is somewhat controversial. The first collected materials were identified as hawthorns, engelmannii Sarg., and Crataegus collina Chapman; one speci- men even was called an Aronia arbutifolia (L.) Ell. Phipps included it within Mespilus in accordance with its multi-stemmed habit, its open fruiting hypanthium, and its camp- todromous venation (having its secondary veins not going directly to the leaf edge). In his description in Systematic Botany (1990), 15(1), pp.26-32, Phipps notes, “... the plant

has the juvenile foliage of some hawthorns, the mature foliage and fruit of a medlar, and is very distinct vegetatively.”

The late recognition of the Stern’s medlar as a distinct species comes nonetheless in the nick of time, perhaps. The plant is so critically endangered in its native habitat that not only is it found in only one location, a 22-acre grove (the Konecny Grove Natural Area, Arkansas), but in this sole native location, it is represented by only 24 . Some observers claim that this population has not produced any fertile seed in some years.

This grove is an ancient remnant of a series of slightly depressed islands of woody flora in a sea of prairie (in Prairie County, Arkansas) that in historical times has mostly been converted to rice agriculture. Although located in horticultural zone 7, our single speci- men is very vigorous in our zone 5/6 setting in East Lansing, Michigan. The genera Mespilus and Crataegus are so closely related that some Crataegus species can hybridize with common medlar, Mespilus germanica. The notched habit of the petals is one indi- cator of Stern’s medlar’s association with the genus Mespilus.

One characteristic that helps solidify the case to assign the Stern’s medlar to Mespilus, is the fact that it can be reproduced from cuttings; a characteristic that is infrequent in the genus Crataegus. This feature allows its multiplication, even before all the salient facts of its reproductive biology have been discovered. It can be obtained commercially, and the species author, J. Phipps, recommends it as the most “exquisite ornamental” out of all the hawthorn/medlar species that he reviews in his book, Hawthorns and Medlars (2003). Our specimen has produced immature fruit, subsequently damaged by , on at least one occasion.