The native plant of the week (and endangered species of the month) that I chose for July is the Sacramento Mountain prickly poppy, Argemone pinnatisecta (G.B. Ownbey) S.D. Cervantes & C.D. Bailey. The plant is similar to the much more common A. pleiacantha, which has already been described in the FB group as a plant of the week. There is some discussion in the literature as to whether or not A. pinnatisecta is merely a subspecies of A. pleiacantha. Cervantes and Bailey seem to be winning that war based on phytochemistry and DNA research, but G.B. Ownbey still gets parenthetical credit because his subspecific epithet gets promoted when subspecies are elevated to species rank.
Whatever its taxonomic status, it's interesting to reflect on what kind of speciation event would have occurred to result in the distribution of the species across its habitat. As its name suggests, it is found in the Sacramento Mountains (Otero Co.). There it exists in a handful of canyons on the western side of the range. This prickly poppy prefers loose, gravelly soils of open disturbed sites; canyon bottoms and slopes, and sometimes along roadsides; 1,300-2,200 m (4,200-7,100 ft).
From the NM Rare Plants website, A. pinnatisecta is described as a robust, herbaceous perennial, with 3-12 branching stems, 0.5-1.5 m tall; leaves blue-green, 10-15 cm long, divided, the sinuses broad and square, margins, midribs, and veins armored with stout yellow spines; stem and leaf latex white (vs yellow-orange in A. pleiacantha); flowers large and showy; sepals 2-3, caducous [falling off after opening, ed.], prickly, each with a subterminal horn; petals 6, white, 3-4 cm long, 8-9 cm wide; stamens numerous, anthers yellow; capsule with many fine spines, none branched; seeds round, black, 2.5 mm in diameter. Flowers May to August.
The number of plants was about 1,300 in the late 1980s, but appears to have declined in recent years. The reasons are unknown; it is speculated plant establishment is very episodic. This rare species appears to be secondary successional, which means it comes into a newly disturbed area after the initial weedy species have had their fling.
You don't have to drive to Alamogordo and hike up one of the 10 rugged canyons where it lives to see this rare plant. It's being grown at the Albuquerque BioPark Botanic Garden for display, public education, research, and conservation of the wild populations. The photos shown here were taken there just a few weeks ago. They are still be blooming as we go to press. They can be found in a large bed on the southeast side of the Heritage Farm between the cider barn and the farm house behind an iris planting and a split rail fence.
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