Pourthiaea sp. indet (Rosaceae) - A common tree in New Jersey without an ID.
Dear iNaturalist community -
We need help to ID a common non-native tree naturalized throughout Princeton, NJ. The tree grows in the Herrontown Woods Arboretum and has been featured in several posts in iNaturalist. This unidentified Pourthiaea was also featured in a blog post by Stephen Hiltner (Princeton Nature Notes). Several posts are listed below.
Please note that we (Stephen Hiltner & John Clark) are confident this is NOT Pourthiaea villosa. P. villosa and the mystery Pourthiaea grow in the same forests, but they are vegetatively different (cf., notes and links below).
iNaturalist observations of Pourthiaea sp. indet. HERE:
https://www.inaturalist.org/observations/117251042
https://www.inaturalist.org/observations/117500236
Stephen Hiltner's Princeton Nature Notes blog post HERE:
https://www.princetonnaturenotes.org/2022/01/a-mystery-tree-in-princeton.html
iNaturalist observations of Pourthiaea villosa HERE:
https://www.inaturalist.org/observations/117251045
https://www.inaturalist.org/observations/117795010
Liu and Hong (2016 – cf., citation below) concluded that Pourthiaea villosa should be broadly circumscribed. They wrote, “variations are continuous or with no statistical support, and there is no correlation between the different characters. Therefore, the characters used in this complex are of little value for species delimitation. As a result of our study, only one species, P. villosa, is recognized, without subdivision. Fourteen names are reduced as new synonyms of P. villosa.. . “
It’s likely that Liu and Hong (2016) are referring to 14 heterotypic synonyms. If you consider homotypic synonyms (cf. POWO), then the list includes 40+ synonyms.
Interestingly, Liu & Hong (2016) did not consider P. lucida as conspecific with P. villosa (cf., note below).
“Pourthiaea lucida was reduced to a synonym of Photonia variabilis. Pourthiaea lucida have compound corymbose inflorescences and conspicuously impressed leaf veins.”
Are there any active taxonomists with expertise in Pourthiaea? Stephen Spongberg (author of Rosaceae for Flora of China) died in 2021. The other author of Pourthiaea for the Flora of China is Ling-ti Lu, who was born in 1930. I could not locate a current institutional address or email for Ling-ti Lu. I reached out to Dr. Hong (citation below), and he responded to my email, but said that he had retired and could not help with the ID (he is 85 years old). I have specimens, but I don't know where to send them. Who else can we ask?
Liu, B. and D. Hong. 2016. A taxonomic revision of the Pourthiaea villosa complex (Rosaceae). Phytotaxa 244(3) 201-247.
http://dx.doi.org/10.11646/phytotaxa.244.3.1
