Cactus Blindness: Its Causes and Treatment

It's time to admit my shameful secret: I have cactus blindness.

Cactus blindness is one of a number of widespread horticultural learning deficiencies (HLD), resembling (and often overlapping with) other HLDs like fern blindness, shrub blindness (I am also considerably shrub-blind, by the way), and palm blindness. Afflicted individuals are easily able to learn and recall names of different cactus species, but are unable to visually distinguish cacti well enough to apply the names accurately to plant specimens.

Ferocactus latispinus? Not particularly confident, but I didn't see much that was particularly close. Flat, yellow, curved spines don't happen a lot. UPDATE: There appears to be consensus that this is in fact Ferocactus latispinus.
Many causes have been proposed for HLDs, ranging from the socioeconomic (lack of exposure to, or accurate identification of, enough plant species in childhood) to the organic (HLDs sometimes occur following stroke or brain injury in previously unaffected individuals). Though below-average intelligence and sensory impairment may also lead to the inability to distinguish cactus species from one another, persons with these conditions are specifically excluded from the DSM-IV definition of cactus blindness, as they lead to much broader difficulties.

Cactus blindness is also distinct from the condition called cactus alexia: in the latter, species are easily distinguished, but the patient experiences great difficulty in learning the names that go with the plants.

I originally suspected this of being a Pachycereus pringlei, and then for some reason decided that it couldn't be, so I switched to Carnegiea gigantea. Carnegiea is fairly common in cultivation (easy to grow from seed), but it's also incredibly slow-growing, which means that it should cost more than these did. So now I'm leaning back toward Pachycereus pringlei. UPDATE: Could go either way, but the smart money appears to be on Carnegiea gigantea.
I bring this up first of all because of Karen715's brave admission a couple weeks ago that she, too, suffers from cactus blindness. Her courage has given me the strength to admit that I, too, find it extremely difficult to identify many of the specimens I encounter. (It is my hope that we can start a support group or something.)

Stenocereus thurberi. Not particularly certain about this, but it does match: newest spines are dark and become lighter, plus the dark areoles -- if it isn't Stenocactus thurberi, it's something that's fairly indistinguishable from it. Also I kind of want this now. UPDATE: Does in fact appear to be Stenocereus thurberi. Yay me.
Secondly, I recently went back to my former workplace and photographed a few cacti there (bought a couple, too, alas), thinking I could identify them easily and then use the photos for yearbook pictures, and I think I even actually did, with great difficulty and the assistance of the photos at cactiguide.com, identify a couple of them. However, some of them continued to stump me, either because none of the 1257 species represented at cactiguide.com looked like the plant in question, or because far too many of them did for me to be able to pick one. (Some of the more questionable photos I took are decorating this post; I welcome any ID verifications or suggestions anybody wants to throw at me.)

Pachycereus marginatus. I'm just, you know, damn positive that I've got a P. marginatus this time. I had previously reported buying a P. marginatus, which for some reason I really really wanted, but I now think that that plant is probably an Isolatocereus dumortieri instead. So now I have this, which I really think probably is a Pachycereus marginatus. UPDATE: Experts agree.
Treatment of cactus blindness typically falls into one of three types. In conventional cactus blindness therapy (CCBT), CB sufferers are encouraged, with the aid of worksheets, photographs, and (when possible) actual cactus specimens, to describe plants in minute detail, with the aim of training the individual to notice the small distinctions between species. This is essentially the training of afflicted individuals to become cactus taxonomists, and while it has a high success rate (about 80% of subjects will become able to identify at least 100 cactus species with at least 70% accuracy), it also takes a considerable amount of time, and requires the assistance of a qualified trainer at all times. Consequently, it is very expensive, and CCBT-certified trainers may not be found in all areas, though cases are known of people who have taught themselves to overcome cactus blindness through informal CCBT-like methods.

Was tagged as "Lemaireocerous." They probably meant Lemaireocereus, though that still doesn't help, since the genus is now obsolete, and the species in it were distributed across five or six other genera. None of the pictures within those genera at cactiguide.com resemble this as far as I'm concerned, and of course we have no real guarantee that Lemaireocereus was the right ID to begin with. UPDATE: I lean toward the suggestion of Browningia hertlingiana (see comments).
The other treatment approach is known as wholistic cactus blindness therapy, or WCBT. WCBT de-emphasizes verbalization of the distinctions between species and instead focuses its efforts on the subconscious: subjects are presented, repeatedly, with randomized pairs of photos or specimens of cacti, and asked to identify whether they are the same species or different species. This, it is said, trains the mind to identify the relevant details which distinguish one species from another, without the tedious completion of worksheets as in CCBT. WCBT is also easily adapted to computer software, making it considerably more affordable and accessible than other therapies. Critics of WCBT point out that it does little to link the image of a particular cactus species to a species name, and is therefore not particularly useful in fostering cactus-related communication. Many WCBT trainers have responded to this charge by adding an additional four-week program to the end of a course of WCBT specifically for the purpose of linking names to the now-mentally-distinct species in the subject's mind.

NOID cactus #2. Lots of stuff looks sort of like this, but the arrangement of the spines (short ones pointing up, left, and right, plus a long one pointing down) seems like it's trying very hard to mean something. I couldn't find a match, and wasted a really ridiculous amount of time trying. UPDATE: I kind of lean toward Mammillaria winterae, though to be safe I think I'll just go with "Mammillaria sp."
Incremental cactus blindness therapy (ICBT), the newest of the CB therapies to gain acceptance, focuses on learning the distinguishing characteristics of only the most commonly-sold or -observed cacti, and those with the most distinctive appearances (e.g. Astrophytum myriostigma, which is fairly hard to confuse with anything else), slowly expanding the pool of one's knowledge only once the initial easy group have been mastered. Its largest advantage over the other methods is that it is more immediately useful than either CCBT or WCBT, enabling the subject to identify several commonly-encountered cactus species after the very first therapeutic session. ICBT is also somewhat adaptable to computer software and requires considerably less of a therapist than CCBT, making it less expensive and easily available. The main disadvantage of ICBT is that accidental exposure to unknown cactus species can result in the mental assignment of mistaken identities, which are frequently difficult to unlearn later on. ICBT also has a rather steep learning curve, which subjects often find discouraging, leading to a dropout rate more than double that of CCBT or WCBT.

To the best of my knowledge, the above therapies have not been attempted with other varieties of HLDs.

NOID cactus #1. This one makes me kind of crazy: I see it for sale all the time, so you'd think it would be easy to find out what it is, but no. I found plenty of approximate visual matches at cactiguide.com, but nothing I could be positive about. UPDATE: Appears to be Parodia leninghausii.
Personally, I'm working a combination of CCBT and ICBT, on my own, with only the internet to guide me, and if I manage to learn anything I'll let you know. Meanwhile, perhaps we should be looking for some available church basements, or setting up a dedicated CB blog, or something. Who's in?

Mammillaria spinosissima. I'm actually pretty confident about this ID; the coloration is pretty distinctive, and I know it's a fairly popular species ("red-headed Irishman cactus"). (UPDATE: Experts agree.) This is one of the two I went ahead and purchased.

UPDATE: Enormous thanks to Daiv Freeman, Peter Breslin, erin, and CelticRose, for their help and suggestions on the NOIDs in this post, and confirmations on the ones I thought I had right.
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Totally skippable political correctness disclaimer and commentary:

I'm not trying to imply that actual learning disabilities aren't real or shouldn't be taken seriously. They of course are, and should. The targets of ridicule here are more the non-disabled people who patronizingly claim every little obstacle's defeat as being inspiring and courageous than for the people who actually have the disabilities, people who try to make unchosen conditions into something shameful, and my own very real difficulty in distinguishing cacti from one another.

Sometimes overcoming disability / adversity / tragedy actually is courageous, of course, but sometimes one never really gets a choice about whether or not to overcome, and in any case it's kind of a weird thing to take someone who has an unusual life situation and single them out as being even more unusual by waxing poetic about their courage and whatever.

As far as it goes, I also don't mean to suggest that the blind are more disabled than others, by using the word "blindness" as part of the term for my made-up condition. It seemed like a better metaphor than, say, deafness, because people generally look at cacti a lot more than they listen to them.

As I have alluded to before, I don't want PATSP to be accidentally offensive to anybody, of whatever age, gender identity, sexual orientation, degree of disability, country of origin or residence, race, mental illness, etc. I want as much of the offensiveness as possible to be on purpose. At the same time, pretty much any reference to certain of these topics is going to be offensive to somebody, however it's phrased, because minority communities don't ever necessarily agree unanimously on PC language, reclaiming slurs, etc. (There's not even total agreement on whether "the disabled" exist as a group, or, if they do, exactly who belongs in it.) So I figure my choices are to never mention these people at all, effectively "disappearing" minority groups into nonexistence, or mention and try to make clear that I'm doing the best I can not to piss people off through my own privilege as a white, able-bodied, cisgendered, American male. (I've been noticing lately that I tend to assume my readers are U.S. or Canadian residents, in a way which probably marginalizes readers from other countries, and have been trying to think of ways to make that happen less often.) I do actually try to think about these things. Sometimes I don't think hard enough.

If I have expressed myself in a particularly inelegant or ignorant way on the matter, please let me know.

Recent new plants: Agave, Zamia, Pachycereus, Myrtillocactus

It's fairly normal for me to go through periods of buying the same kind of plant, or sometimes even multiple copies of the exact same plant, and then realize that I was doing this only somewhat later. Most of my orchids all arrived at about the same time, for example, as did most of my African violets (which also all left at about the same time, too: African violets are social plants, and travel in swarms).

Lately I seem to be having a cactus period: in addition to the Astrophytum ornatum I mentioned a while ago, I've also gotten a couple other cacti recently, plus an Agave which, though not a cactus, shares enough characteristics with cacti that I think we can include it as an honorary cactus for these purposes.

Myrtillocactus geometrizans ("whortleberry cactus"). Or at least that's how Lowe's had it marked. I blame Cactus Blog for this one: they'd posted about Myrtillocactus a couple times in the days before I bought this (mid-August). I'm not positive, but I think the cost was something like $4 or $5.
UPDATE: I now believe this is probably not a Myrtillocactus after all, but a Stenocereus pruinosus. This is based on their respective photos at cactiguide.com.

Pachycereus marginatus, I think. I'd wanted one for a while, but it took me until mid-October to remember that there were some at the ex-job. Not positive on the ID, but hopeful. It cost about $5.
UPDATE: I now believe this is an Isolatocereus dumortieri. Which I am okay with.

Zamia furfuracea? It's a very young Zamia ("cardboard palm" -- though it is neither), anyway. From a hardware store in Iowa City. We'd had these at work before, as much larger, less full plants, and they stayed around for over a year without selling. Then they suddenly all got scale of some kind and we threw them out. (It was more like seven out of eight got scale, and we couldn't be positive about the eighth.) I would have bought one way earlier, but for size and price. This was very reasonable ($6-7?), and only in a four-inch pot, so it got to come home with me about three weeks ago.

Agave 'Blue Glow.' Speaking of getting things in that then don't sell, I suspect Wallace's, in Bettendorf, is feeling this a little. They have a lot of fairly cool Agaves there in four-inch pots, which I think they got in in the spring for people to use in succulent plantings outside. They still have a lot of them left as of Halloween, when I bought this. 'Blue Glow' is supposed to be a hybrid of A. ocahui and A. attenuata. Leaves are a very cool blue-green, and have yellow and red spines on the leaf edges which are easier to see in the full-size picture. This was also about $6, and the plant had offset, so I got two plants out of it.