I've started collecting a whole bunch of these, but some I just can't tell for the life of me what they are. Some are just too ambiguous for me right now to tell exactly what they are. The blue columnar cactus: 2.5 inches tall and 1.75 inches wide currently. There are 11 ribs, fairly well divided. New growth of the spines is orange. older spines are pale yellow. They are fairly flexible. Roughly 11 spines on each areole, give or take. Areoles of the newer growth seem a bit wooly. Could it be a Pilosocereus or a Micranthocereus? The green columnar cactus: three inches tall. 15 going on 16 ribs. close together. The spines are yellow and though they are thin, they are fairly stiff. The central spines are thicker than the radials, though they still have some flexibility and are all sharp. Looks like 12 short radial spines. One or two longer central spines. The round, short, green cactus with long spines: This came off a four or five year old cactus I’d had. It was extremely sensitive to light and if not in intense light, would become stretched out. This year had good growth, so I lopped off the top to try anew. It had been growing as if it may be columnar with time. It is an inch tall, and this was the last year’s growth. two inches wide Twelve ribs deeply divided. Areoles getting hairy at top. New to this year. Areoles are variable with the spines. Roughly 13 around outside, sometimes four central spines. Sometimes one defined central spine. Spines light brown with a tinge of tan-pink New growth near-white yellow. Outermost spines very thin, then some thicker spines, and innermost are most thick. All very straight, very stiff. Am I getting my hopes up to think this is Carnegia gigantean? Round, green, tiny spined cactus: 1.75 inches wide 1.5 inches tall Looks like there may be two rows of spines. Roughly 8 on outside, 4 on inside (on a more mature rib) less spines on newer growth. White new growth. Mature spines yellow with tinges of orange. Ribs are small bumps growing in spirals from bottom to top going left to right. Is this a rebutia? The wavey ribbed tiny cactus. (stenocactus?) I could not find a stenocactus online with features similar to this, but I wonder if the cactus merely changes with age. (or if I just have the most severely shriveled, underwatered cactus (I hope not)) 1.5 inches wide 1.25 inches tall 13 ribs currently Roughly 10~11 radial spines, some white some red. one fishhook central spine, and though it is tiny, it does appear somewhat flattened and wide and not simply round. Older spines become white. On lower waved ribs, the areoles are not simply round, but protrude a bit up and down the ribs. What looks to be buds, or spent flowers, (more likely the latter) are in the shapes of the top of a pineapple and are tan. Great thanks in advance. :}
Maybe. They usually flower early, were there no dried-up flowers on the lower half of the body? How about Hamatocactus/Thelocactus setispinus? (Or possibly Hamatocactus/Ferocactus hamatacanthus, I have heard that they can look similar, even if mine have been very easy to tell apart.) The rest are columnars, which I am not familiar with. :-(
There were no flowers on the perhaps-rebutia, it's still a fairly small plant though, so maybe it'll only flower for the first time this upcoming year or later. The Hamatocactus is right on! I've never even heard of that genus before. I think it may be Hamatocactus longihamatus because of the longer fishhook spines and especially the areoles that stretch vertically onto the ribs. But this plant is tiiiiny, so it'll need some growing before one could tell what it really is, I would think. Thank you so much though. That was really helpful. :)
I just found this horrible picture of the same species that I believe may be a Carnegia gigantea. Though I am sceptical because the spines are yellow where the Carnegias that I have seen have grey spines. The picture is ridiculously blurry, it was just in the background of a picture of a different plant, but I cropped this out of it so that the general shape of how the plant should be growing is seen. I had two of these plants. This blurry one died because of overwatering. A long time ago when I knew less about the plant. But I hope the shape of the plant could be of some help. All of the descriptive features would be the same though of the plant that I still have that I have a much more clear picture of above. Thank you for any help you can provide.