Mammillaria plumosa, fall flowers usually white or cream, here with pale pink stripe

Part of the magnetism of cacti and succulents is their strangeness—how they differ from mundane plants. Even more fascinating are the strangest-of-the-strange: cacti and succulents which have evolved bizarre features or eccentric adaptations.

Enter Mammillaria plumosa. It’s a cactus and it has spines, but these “spines” have evolved differently. They do not pierce or prickle. Instead, they sprout from each areole like tiny fountains of feathers. They certainly protect the body of the plant—but it’s the soft protection of plumage rather than the hard protection of armor… or the outright weaponry of your typical cactus.

Mammillaria plumosa forms clusters in calcareous rock clefts of Coahuila and Nuevo Leon in Northeast Mexico, home to many gorgeous and desirable cacti and succulents… such as Ariocarpus scaphirostris, subject of a previous Succulent Sunday. Like many cacti, it is protected on List II of CITES international wildlife treaty.

Mammillaria plumosa, photo WindsurfGirl at Flickr

Mammillaria plumosa is popular with home growers. (Yes, home growers. I hate the C word, collectors.) It is not terribly difficult to grow if you don’t keep its roots too wet during cold weather. Or at least that’s what they tell me. So far, so good! Pictured is my plant blooming happily in a mix of 95% pumice, a naturally airy volcanic rock. This should help avoid the dreaded root rot. Time will tell; our first winter together is knocking at the door—this week with freakish 90 MPH winds in Los Angeles! Ah but the winds aren’t as dangerous to cactus as wet combined with cold.

Mammillaria plumosa rewards proper care by regular flowering (usually white but sometimes with a light pink midstripe), especially in autumn. And it spreads outward to form a clump. These clumps can be divided. Separated heads are reported to grow new roots with some ease. This makes it the best kind of long-term project for the home grower—your growing success is rewarded with more plants which you can give away to your friends.

And they look good.

See also

Mammillaria plumosa article at Cactus Art

Mammillaria for sale at Miles’ To Go cactus nursery

From The Cactus Family by Edward F. Anderson (2001):

Mammillaria plumosa F. A. C. Weber 1898

Feather Cactus

Chilita plumosa (F. A. C. Weber) Orcutt 1926, Ebnerella plumosa (F. A. C. Weber) Buxbaum 1951

Plants forming low, dense mounds to 40 cm (16 in) wide. Stems globose, light green 6–7 cm (2.4–2.8 in) high and in diameter. Tubercles very soft, cylindrical, without latex, axils woolly. Central spines absent. Radial spines about 40, plumose, white, 3–7 mm (to 0.3 in) long. Flowers white, to 15 mm (0.6 in) long. Fruits club shaped, deep purplish rose, to 15 mm (0.6 in) long. Seeds blackish brown to black. Distribution: Coahuila and Nuevo Leon, Mexico.

Ariocarpus scaphirostris, extremely rare, occurring only on the Valley of Rayones, Nuevo Leon, Mexico. It is endangered by unscrupulous collectors… and reportedly by goats, which damage their habitat. This 2-inch plant is probably at least 8 years old — minimum flowering age.

I was in the full throes of enthusiasm when I obtained this rather costly little plant. By enthusiasm I mean the old sense of  divine inspiration or frenzy. This frenzy — probably a dopamine buzz — always grips me in the sales area at cactus and succulent plant shows. To my friends, I apologize if I seem dizzy or distracted. It’s because my mind is bathed in an unseen, golden haze.

It’s both embarrassing and enthralling to be an enthusiast — almost any kind of enthusiast, but particularly a plant enthusiast. Embarrassing because it’s so personal, so particular, so quaint, so… geeky. Enthralling because the object of our enthusiasm brings such immediate fascination, such transfixing attention, such passion.

As soon as you reveal a passion, you make yourself vulnerable — this is true with any declaration of love. How much moreso with plants? For one thing, the love is always unrequited. And it’s such an obscure, unusual love. It’s a little like loving, say, mathematics. (Guilty!) And yet it’s much more humble, more homely, almost banal… literally down in the dirt. Face it, you are out on a limb — a plant limb — and it feels awkward.

Same plant in full bloom 3 days later. In habitat, only the tips of the leaves (and flower) would be visible above the gypsum shale scree. (And yes, I just enjoy writing gypsum shale scree.)

Like most passions in life, if you have to explain it, no words will suffice; yet to another enthusiast, no words are necessary. The beauty of the forms, the plants’ names and stories, the technical details of habitat and how to care for the plants — these crossbeams interlock to build first a frame and then a fully furnished room in the house of one’s life (or at least to take over the backyard… sorry honey!).

Today’s plant, Ariocarpus scaphirostris (also spelled scapharostrus for historical reasons) is an obscure beauty — literally obscure. In nature it spends its entire life hidden underground with only the tips of its tubercles exposed (those thick protuberances). And even its tubercles when dusty blend perfectly into the landscape, looking exactly like the shards of gypsum shale which litter its habitat.

This complete camouflage is demonstrated almost miraculously in — of all things — a YouTube video.

Ariocarpus scaphirostris is also obscure because it lives in such a limited area, only Valle de Rayones, Nuevo Leon, Mexico. This rare plant is endangered by collectors and, it turns out, by goats which range the slopes where it lives and damage the landscape. Luckily more and more folks in Mexico (and internationally) are coming to recognize the irreplaceable resource of Nuevo Leon‘s native plant life, including this almost invisible geophyte (plant living mostly underground).

Ariocarpus scaphirostris is vulnerable, but its outlook is improving modestly as passionate individuals raise its conservation profile in Mexico and the rest of the world. This plant is small, it’s slow, it’s difficult, and it’s hard to come by. Most of the year it looks like twisted green rocks. But I think it’s beautiful, and this was its first flower under my care.
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Ariocarpus scaphirostris at CactusArt.biz
Ariocarpus scaphirostris at CactiGuide.com
Ariocarpus scaphirostris at Living Rocks of Mexico