PHILANTHROPY AND PHILODENDRONS
Cactaceae
The flowers of the cactus family are very distinctive, which makes it much easier to distinguish a cactus from other vegetatively similar plants like the desert adapted species of Euphorbiaceae.
They are also a major identifying trait of the species shown to the left, Pereskia grandifolia. This plant and others in its genus are more often confused for one in the Rosaceae family, or even Magnoliaceae.
This is because the Pereskia genus is a basal lineage of Cactaceae, so it does not have many of the characteristic traits other cacti do.
Something else to note is the 'irregular' fruit shape of Pereskia. Cacti fruit are botanically classified as berries, and I had read online that Pereskia berries are somewhat irregular, but I did not understand what that meant until I saw it.
The fruit is quite literally irregular. I found a number of fruit both on the plant itself and on the ground, and all of them looked roughly like this but with different folds/wrinkles. Looking on iNaturalist, some of the fruits even have leaves on them.
I also included a photo of the bottom of the fruit which shows the remnants of the flower and allows us to tell that the flower has an inferior ovary.
Below the fruit is a photo of the flower of Pereskia weberiana, a related species native only to Bolivia. I do not have any photos of the fruit for this species but iNaturalist posts show it being smaller and turning from green to a dark purple.
Flowers of the cactus family are characterized by a singular, large, long style with multiple tentacle-like lobes. The number of lobes ranges in number depending upon the species, but in my experience they usually range from ~6-14.
They also have numerous stamens and tepals. The tepal colors are generally warm colors, as shown in the photos below.
Image description: Flowers of Gymnocalycium mihanovichii
Image description: Flower of Pereskia grandiflora on UC Davis campus
The images of the blood-red flowers to the right are from Echinocereus coccineus. This species is native mainly to Texas, New Mexico, and even up into Colorado, and extends southward just into northern Mexico.
One source I read, @tom.mathies on Instagram, shared that the flowers of this species remain open throughout the night. This is due to the fact that they are primarily hummingbird pollinated, unlike the majority of cacti which are bee pollinated. Because the hummingbirds remain active earlier and later on in the day than bees do, this species of cactus has uniquely adapted to keep its flowers open to maximize pollination success.
Flower Remnants
Ring of flowers
This Mammillaria haageana has much smaller flowers which often form a ring around the top of each stem. This 'crown' of flowers forms because the flowers grow out of the newest mature nodes, with the immature nodes growing from inside the ring and the nodes that are too old outside the ring, running down the sides of the stem. Unlike the Echinocereus coccineus, this species is pollinated by bees and grows further south, just below Mexico City, Mexico.
These last two cacti are Echinocereus sheeri and Tephrocactus alexanderi (syn. Tephrocactus geometricus). Both of these species are well known among collectors due in part to their large, beautiful flowers. The E. sheeri has twelve stigma lobes, while the T. alexanderi has six.
Floral Formula
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