Thursday, March 14, 2024

South Dakota Tree-Following—Prairie Crabapple

Pyrus ioensis. 1913, Curtis's Botanical Magazine. Source.
This month's tree-following report features another tree from South Dakota, part of my effort to learn more about the state's trees. There's a practical reason for this—I'm writing species descriptions and selecting photos for an online Guide to Trees, Shrubs, and Woody Vines of South Dakota.

Having recently worked my way through the challenging Rose Family (see post about the diverse and complicated fruits), a Rosaceaous tree was the obvious choice. I picked one new to me—Prairie Crabapple, Malus ioensis (formerly Pyrus ioensis).

I also wanted to showcase photos from Minnesota Wildflowers (now includes all plants not just wildflowers). It will be a major source of photos for our guide as our states share many species. Almost all their photos are free for non-commercial use (that would be us!), there are tens of thousands to choose from, and the photographers are botanists who know what's needed for identification. The Prairie Crabapple is a fine example (photos below are from the website).

Prairie Crabapples grow as shrubs or trees to 6 m tall, and can form dense thickets from root suckers.

Malus ioensis in bloom, hence the pinkish tinted crowns.
Prairie Crabapple leaves by Katy Chayka, creator and driving force of Minnesota Wildflowers.

With maturity, bark develops irregular ridges or plates that peel away to reveal reddish inner bark.
Prairie Crabapple flowers are typical of the Rose Family, with five showy-but-simple petals surrounded by five sepals. Inside the petals are numerous pollen-producing stamens surrounding a pistil containing ovules awaiting fertilization to become seeds.

Flower bud showing fuzzy sepals. These help with id.
Botanically speaking this crabapple is "armed", in this case with short branches that become sharp-tipped. Technically these are thorns, which are derived from branches or shoots (vs. spines which develop from leaves, and prickles which develop from the outer layer of a stem or branch; there's a Wikipedia article devoted to this topic).
Thorn developed from short flowering shoot.
Fruits of crabapples are pomes, from Old French "pome" meaning apple. Those of Prairie Crabapple are only about 2.5 cm across. They are "edible but barely so" according to Katy.
I'm looking forward to seeing Prairie Crabapple in the wild, of course! But there's a problem. Though multiple sources report it for South Dakota, I found NO specimens in a search of SEINet, the online portal to digital herbaria across the country. And the South Dakota Natural Heritage Program, which tracks rare plants, lists it as "Reported for woodlands of e SD, no vouchers yet found." I may be off on a treasure hunt once spring comes.
USDA Plants shows Malus ioensis in Lincoln, Clay, and Codington counties in South Dakota. Unfortunately no evidence or sources are provided (arrows added).

This is my contribution to this month's gathering of Tree Followers, kindly hosted by The Squirrelbasket. Once again—if you're looking for a good time, I invite you to join us!


Minnesota Wildflowers. Malus ioensis (Prairie Crabapple).

Flora of North America, Malus ioensis.