Flower:

Flowers are displayed in an open array on slender stalks that diverge near the end of a long smooth stem. Flowers are 1/3 to ½ inch across, star-shaped with 5 pink petals and up to 25 erect pink stamens with bright yellow tips. The ovary is a small green globe at center, the style white and slender split into 3 parts at the tip. Two papery thin oval sepals embrace the base of the flower. Flowers are only open for a few hours in late afternoon in full sunshine, rapidly closing up before the sun goes down.

Leaves and stem:

Leaves are round in cross-section, linear and succulent with a smooth, transluscent sheen, 1 to 3 inches long attached to a compressed stem on a taproot. The flowering stem is naked and very slender, and sometimes branched.

Fruit:

Fruit is a green globe-shaped capsule around 1/6 inch in diameter, containing seeds with a very wrinkly texture, hence the common name Rough-seeded Fameflower.

Notes:

Rough-seeded Fameflower was first discovered in 1864 near Taylors Falls by a surgeon and Mississippi headwaters explorer but not identified to its own specific epithet until 1899 - Talinum rugospermum. Recent taxonomic studies have changed its classification to Phemeranthus rugospermus. According to the DNR, it is relatively rare throughout it range due to its narrow habitat preferences. While classified as State Endangered in 1984 and downgraded to Threatened in 2013, its seed is available from native seed peddlers and I have found it to germinate easily and persist quite well in a sunny, sandy garden spot, though it will not tolerate much competition so must be carefully cultivated.

Fameflowers are well adapted to their hot, dry sunny habitats by their small cylindrical and succulent leaves, short fleshy stem and even a flower period set to late afternoons and early evening. The flowers open quickly for just one day and then quickly shed sepals and petals before the next sun-up. Minnesota's two species, Rough-seeded and Small-flowered Fameflower (Phemeranthus parviflorus) are very nearly identical in general appearance though easy to discriminate on several key characteristics. Perhaps the easiest might be that historical collections do not overlap in a single county (see maps). While that may suffice as a quick general guide it could easily provide the wrong answer - i.e. just because no one has found it somewhere before doesn't mean its not there now. The best way is to count the stamens. Rough-seeded Fameflower has anywhere between 12 and 25, typically +20, small-flowered only has 5 to 10 stamens, typically 6 to 8. It should be noted here that all major references (Gleason & Cronquist, Britton & Brown and FNA) are consistent with P. parviflorus having typically 5 stamens, 6 at most. But all of our observations and in photographs of specimens taken from Renville, Rock and Stearns counties, all of them have had 6 or more with 7 or 8 common.