Microphotography: Portulaca grandiflora

I'm unclear on the specifics of where and how, but the husband, knowing that I've been looking for a microscope for some time, somehow obtained a used one for me. Which is one example of how he's the best husband ever.

The catches -- and of course there are catches -- are:

1) Okay, I don't know the proper names for anything here, but I'm going to call that thing in the middle, with the four things sticking out from it, the microscope's "udder," because that's what it looks like. Each of those barrels on the udder has a different level of magnification (I don't know what levels of magnification, because I cannot decipher what the barrels say), only two of which appear to function.
2) It's a regular, old-school, 1960s-ish microscope, so it wasn't designed with digital photography in mind. If the camera lens is not exactly centered over the eyepiece, the camera doesn't register anything being there at all. Likewise if it isn't precisely the right height above the eyepiece. My hands shake way too much to get pictures by holding the camera in the right spot myself, and although we do have a tripod, the base of the microscope is just large enough to get in the way of the tripod's legs, so I can get within about a centimeter (0.4 in.) of the eyepiece, but then no further. Except! When I took the below pictures, I actually could get the tripod directly over the eyepiece. I just couldn't do it again a few days later when I moved the whole thing outside to try to get a better set of pictures in stronger light, and I don't know why, and the whole thing was very frustrating. Which leads us to the third problem, which is:
3) Even when I do manage to line the camera up, using the tripod, the amount of light coming through the eyepiece is small, so my camera uses long exposure times, which results in blurry pictures, even at its best.
4) And at its worst, the camera autofocus chooses to focus on the eyepiece itself, instead of the image in the eyepiece. Or it focuses on some part of the microscope outside the eyepiece, so I get a perfect shot of the top of the udder but the actual image I'm trying to capture is too fuzzy to make out.

So the point is that there are some problems with this, and you should, consequently, not expect to see a lot of these pictures until such time as I can figure out how to get better ones. And I would love some suggestions from other people, because I know there's got to be someone out there who's taken photographs through a microscope's eyepiece successfully.

Having said all of that, there have been some pretty cool moments with the microscope already, which I will hopefully be able to share with you someday. Portulaca grandiflora seeds, my only successful photos to date, turn out to be much more interesting than the gray, metallic dust they appear to be with the naked eye. For example, I had always imagined them as more or less spherical, since a lot of seeds are, but they turn out to have a specific, weird shape, somewhere between a comma and a nautilus:

At the higher magnification, they also have an unexpected texture, which is probably the coolest and most surprising thing I've seen in weeks. It didn't photograph well, of course:

The pattern is sort of approximately that of a bunch of tiny interlocked cogwheels, covering the whole surface of the seed. Which is even stranger in combination with the overall iridescent metallic gray color. (I now suspect that Portulaca grandiflora are robotic plants.)

I also tried for photos of the pollen, but that went even less well, and wasn't very interesting:

And those are the only actual pictures I'm able to provide to you at this point. Possible coming attractions, if I can figure out how to take the pictures:

A lot of leaves are hairier than I would have guessed. (Pedilanthus being the most surprising.) Though most leaves are disappointingly boring.

The serrated edges on Yucca guatemalensis are a lot less regular in shape and spacing than I expected.

Cryptanthus pollen is even more dull than Portulaca pollen: basically just irregular little white rounded things. At least Portulaca pollen has a color to it.

Ceropegia woodii flowers look exactly the way you would expect them to look, and brought to mind both "eyelashes" and "houseflies." Aeschynanthus speciosus flowers are boring and look just like they do with the naked eye, except bigger. Neofinetia roots didn't do much for me. (Think "styrofoam.") The Euphorbia fungus (yes, I still have Euphorbia fungus) looked exactly like I expected (sort of a creeping white net), and was dull.

Broadleaf plantain (Plantago major) really does have flowers (when you let it bloom), and the flowers are actually sort of pretty. I mean, if they were twenty times bigger, you'd grow the plant as an ornamental: there's a white, fluffy bottlebrush sort of stamen, with lots of white spherical pollen grains, and then the stigmas, or something I take to be the stigmas, are sort of shaped like white tulips with purple stripes down the center of each petal. (Plantago major is high on the list of stuff to get pictures of, whenever I figure out how to do that, but you can get some idea from the picture here at Wikimedia Commons. There must be some natural variation, though, because that's a darker, solid purple than what I was seeing.)

Another high-priority item: Anthurium spadices. It's a little easier for me to believe that those are flowers, now that I've seen them close-up. (I'd link to a photo, but I couldn't find one easily on Google image search.) It should probably be noted that they're still not pretty. At best, interesting.

Spider mites are every bit as horrifying as you'd think they would be, and they will continue to suck sap out of a leaf even after it's been removed from the plant. They also do this weird thing where they either shake their back legs like a dog getting a belly rub, or they rub their rearmost pair of legs together like a person trying to warm their hands. I only saw it do that once, and it was fast. I was so surprised and freaked out by there being, suddenly, movement, that I can't tell you exactly what it was. It also convinced me to throw the leaf in the trash more or less immediately afterward.

I think I've seen spider mite eggs now, though they weren't all the same color, so I'm not 100% on that. (They were all somewhere in the yellow or yellow-orange color range, but the darkness varied a lot, from pale yellow down to almost black.)

Some unknown white thing that was on our lettuce was one of the scariest things I've ever seen. It somehow managed to evoke deep-sea crabs, skeletons, spiders, and ghosts simultaneously, and I'm pretty sure seeing them come into focus in the microscope took a year off my life. The best match I found on-line for them was here, on a forum where they were identified as the shed exoskeletons of a molted aphid here. (The pictures at the link aren't magnified enough to be upsetting, FWIW.) So "skeleton" and "ghost" were actually pretty close. That also explains why they weren't moving.

So the point is, there's a lot of potential for interesting new posts, if only I can figure out how to get the pictures. It's going to take some experimentation, and I only have so much time, so if anybody has any relevant expertise, I'd sure appreciate hearing from you.

Random plant events: white flowers

Nothing gigantic and incredible going on exactly, but I've got three plants blooming recently that are all notable in some way or another, and as it happens, all three have white flowers, so it seemed reasonable to group them together into one post.

First up is the Coffea arabica, which struggled a bit this winter (dropping the lowest leaves, mostly, which for all I know is normal) but just got super excited and put out a huge flush of flowers.¹

I counted flowers at 38 separate nodes. If each node produces 2.5 berries (previously, either 2 or 3 seemed to be standard), and each berry produces 1.9 seeds (also based on previous experience), that's roughly 150-200 seeds.


The husband pointed out that 150-200 seeds might actually be sufficient to make a cup or two of coffee. I'm a little bit tempted, but I'd be more inclined to plant the seeds and get more plants. Assuming that there are seeds. Also assuming that the seeds will germinate.² (Obviously there's a great deal of premature chicken-counting going on in this paragraph.)


I tried, but was unable to get any smell from the flowers at all. (The husband could, so I'm not sure what my problem is.)

Next up, I've got flowers on my Haworthia limifolia var. limifolia. This isn't the first time that one of the Haworthias has attempted to bloom, but usually the flower spike shoots up into the fluorescent lights and then burns before I notice it, or it starts to grow deep within the leaves and then stalls and dies for some reason. I don't know for sure that this is the first time I've ever had one reach full bloom, but it's the first in a very long time, at least.


There is a chance that H. limifolia var. limifolia may be self-fertile: some Haworthias are and some aren't, from what I hear. I won't be attempting to get seeds from this one, though, because the flowers are so tiny and easily damaged that I doubt I have the necessary visual acuity and fine motor control. (If you've got a flowering Haworthia of your own that you want to try with, you'll want to check this out.)

Finally, I think most of us have seen Cryptanthus flowers before, and I've never found them all that interesting or attractive, but these made me do a double-take:


I think Cryptanthus flowers are always white,³ so the color's not a big deal, but I was struck by the size and shape: ordinarily they're small, flat, triangular things that are easily overlooked. This particular plant (a NOID), though, produces flowers that are a bit larger, and more trumpet-shaped. It's not a huge difference, but it was enough to make me think, oh, those are really pretty, for a Cryptanthus.

I won't be collecting seeds from this either, first because there are no other Cryptanthuses blooming at the moment so I have nothing to cross them with, second because the recent failure with the Cryptbergias has made me doubt I could pull it off, and third because there are much easier ways to get more Cryptanthuses, if more Cryptanthuses is what you want, and I've already got so many baby plants from offsets that I have no idea what to do with them all. But let the record show that I totally thought about it.

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¹ Google says that the bloom season is "mid spring" or March, both of which apply. So I guess everything's normal.
² This might be a good moment to update you on the progress of the Coffea seeds I started on 18 February. It's an easy update: absolutely nothing has happened yet, as far as I can see. This is not surprising; Coffea seeds are slow germinators, and right now, at one month, is the very soonest I could have expected anything to happen. Two months seems to be typical, according to Google; some sources say as long as four. (Nobody claims anything faster than 1 month.)
I'm also wondering if I maybe got some bad information; a lot of the sources I found while googling for germination times also say that seeds that have dried out too much are generally non-viable. The plan I was working from initially said that viability was best with seeds that had been dried for eight weeks, so somebody has to be wrong here. I'm starting to get a little anxious.
³ (I've never seen them in any other color, anyway.)

Ten(-ish) Things I Have Mistaken for Scale

So we're in the fifth week of checking all the plants in the basement weekly (on the east and south sides) or every second week (on the west). I'm not finding many actual pests anymore, for two reasons:

The first reason is that there's just not that much to find anymore, since any plants with obvious, easy to see infestations were already thrown in the trash.¹ The second is that I'm not looking as hard, because it's extremely time-consuming and tedious to do, and I'm tired of it.

As a result, almost every scale insect I've seen lately has been a false positive of one kind or another. And there are many kinds. So here is a list of ten things I have managed to mistake for scale in the last five weeks:

1. Scars -- on everything. Oh my god. You've never imagined how many little tan corky spots there are on the leaves, petioles, and stems of your plants until you've had to check each one individually to see whether it rubs off. And of course there's no way to actually remove them, because they're part of the plant, so I wind up checking the same scars over and over, week after week. This is far and away the largest and most irritating category of false positives.

Multiple scars on Epipremnum aureum 'Neon.'
Leaf scar on Manfreda undulata 'Chocolate Chips.'
Not actually sure what this thing on a NOID Cryptanthus is, but I think it's either edema, a scar, or edema that became a scar.
Multiple irregular scars on the back of a Begonia x 'Erythrophylla' leaf.
Scars from thrips (?) on one of the Anthurium seedlings.

2. Dots of dried sap -- they're generally the wrong color to be scale, but the size and shape are close, so they have to get checked out anyway. Arguably a subcategory of scars, though distinct because dried sap rubs off. (Usually.)

Dried sap on Euphorbia trigona.
And on Hoya something. (Sold as H. kentiana, probably actually H. wayetii.)

3. Marginal burn, tip burn -- It doesn't happen a lot, but sometimes when a leaf is burnt in just the right way, the dead spot looks like a scale insect hanging right on the edge or tip of the leaf. Since the actual insects tend to congregate around the spot where the petiole attaches to the leaf, on and along the midrib and other major veins, this isn't terribly confusing, but it happens.

The margin spots on this variegated Yucca guatemalensis didn't make it through the recoloring / cropping process in very good shape, but they're there, along with a more obvious scar in the center of the leaf.

4. Aerial roots -- the shape is often not quite right, but when they're first developing, some aerial roots are small, oval, and tan. Best distinguished from scale by the facts that they don't wipe off and that they're pointy.

Aerial roots on a somewhat unhappy Selenicereus anthonyanus.²
Roots forming on a Stapelia gigantea stem.

5. Dirt -- dirt gets splashed all over when I water, so some of it ends up on the leaves and stems. Because there's no wind in the basement to blow it off, it stays attached. The irregular shape usually gives it away, but some pieces of bark are rounded enough to be momentarily alarming, and vermiculite is about the right color, so this is occasionally a problem.

A tiny fleck of potting mix on an Aglaonema 'Peacock' leaf.
A couple bits of dirt on an Anthurium seedling.

6. The natural coloration of the plant -- some plants just naturally have lots of little bumps or brown spots or whatever. In most of these cases, I've either given up on checking altogether because it's impossible, or the plant got scale a long time ago and has been thrown out. Aerial roots is technically a subdivision of natural coloration, now that I think about it, but it's so common and specific it probably deserves a separate entry anyway.

Close-up of a Ficus microcarpus stem, showing peeling bark, aerial roots, and a bunch of other random stuff.
Some of this Schefflera actinophylla's brown spots, if not all of them, are capable of becoming aerial roots if the air is sufficiently humid, but usually they just expand to form bark.

7. Edema -- again, bumps due to edema are usually irregularly shaped, so I don't have to resort to the squish test, but this has still happened plenty of times.

Surprisingly bad edema on a Billbergia nutans leaf, probably because I moved it into a bigger pot and then set it in front of a cold window.

8. Spiders -- only once, but still.


9. Mineral deposits -- parts of the plants that are in contact with the soil will sometimes get a tan, crusty mineral buildup which can resemble a big infestation of closely-spaced scale. Hatiora salicornioides seems to be especially prone to this, but I also see it on Anthurium quite a lot.

Mineral crust on Hatiora salicornioides.

10. Hallucinations -- and occasionally I just straight-up see things that aren't there. Which is usually a sign that I should take a break.

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¹ The last few scale insects I've found also appeared to be dead already. Or at least they were really, really tired, being flat and dried out and crunchy. One hopes that this has something to do with the imidacloprid.
Although thrips aren't really the focus of the post, for readers who are curious: the thrips are still around, here and there, and when I see them they're generally alive. I'm only finding them in a particular fairly narrow section of the basement shelves, though, and I didn't find any last week, so this is maybe progress. I also got my first thrips photos -- none are very good, but they're an improvement over no photos at all:
The thrips in question was photographed on notebook paper (hence the blue line in the top image), through a tiny magnifying glass lens, if this gives you any sense of the size.
² I have two Selenicereus anthonyanus plants, one in the basement and one in the plant room, and neither one has ever seemed very happy to be here. Mostly they just don't grow very fast, and the new growth is thin. Likely a light issue, but I don't have any better spots available.
It's weird, because Selenicereus chrysocardium is fine in very similar spots. I don't know what's wrong.

Rumble Among the Jungle, Matches 3.1 and 3.2

Rules and Stuff
1) It's probably possible to vote more than once per poll, but please don't. If I believe that someone is voting repeatedly, I will throw out those results, repost the poll, and seriously question that person's priorities.
2) If you want to link to a poll on Twitter / Facebook / your blog / whatever and encourage your friends to come and pump up the support for your favorite plants, you are encouraged to do so.
3) You are also encouraged to leave comments on Rumble posts, if so moved.
4) All photos will enlarge if opened in a separate window/tab.
5) You can choose which plant is "best" according to whatever criteria you decide for yourself. My personal process is a bit convoluted.¹
6) All polls will be open for three days.

Results for matches 2.17 to 2.20:

In match 2.17, Dionaea muscipula made a good effort against Aeschynanthus cvv., but faded early, letting Aeschynanthus accumulate a slight lead. Which then turned into a bigger lead. Dionaea loses, 48 to 64.
Match 2.18 was a bit more complicated -- this was another one where the contestants swapped the lead back and forth a number of times before settling on a winner. In the end, Aechmea fasciata just didn't quite have what it took, falling to Spathiphyllum cvv. by 54 to 61.

Aeschynanthus cvv. goes up against Spathiphyllum cvv. in match 3.9. Voting begins on 19 October.

Pilea involucrata 'Norfolk' didn't really stand a chance against Chlorophytum comosum, in match 2.19: it lost 36 to 78.
In match 2.20, Echeveria cvv. (and relatives) absolutely beat the tar out of Kalanchoe luciae / thyrsiflora, winning 91 to 23. This is the second time that Echeveria et al. have gotten more than 75% of the vote; the only other competitor to do so thus far has been Saintpaulia cvv. This may mean that Echeveria is a serious contender for the championship, but it could also mean that it got some exceptionally wimpy opponents. Time will tell.

Chlorophytum comosum will try to break Echeveria's winning streak on 19 October, in match 3.9.

We are now ready to begin the third-round voting. I'm slowing things down a little and only posting two matches per day during round 3. I'll slow down even further (to one match per day) once we start round 4, about a week from now.

Match 3.1
Clivia miniata cvv. vs. Cryptanthus cvv. (earth star)

Top: Clivia miniata. (Picture by Guérin Nicolas at Wikimedia Commons.) Bottom: NOID cv.

Clockwise from top left: C. 'Elaine,' C. 'Black Mystic,' NOID, NOID, NOID.





Match 3.2
Saintpaulia cvv. (African violet) vs. Epipremnum aureum cvv. (pothos)

Saintpaulia cvv.
Top row, L-R: NOID, assorted NOIDs, NOID.
Middle row, L-R: NOID, NOID, NOID.
Bottom row, L-R: 'Harmony's Red Star,' 'Mellow Magic' close-up, NOID.

Clockwise from top left: Epipremnum aureum 'Neon,' 'Marble Queen,' 'N'Joy,' trained on a totem.





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¹ I'm deciding according to a hypothetical situation in which all of my houseplants are gone, as are all the other houseplants of the world, except for one producer/supplier/retailer. Said person is offering to restock me with one or the other of the plants in question but refuses to give me both. Which one would I choose?

Rumble Among the Jungle, Matches 2.1-2.4

Rules and Stuff
1) It's probably possible to vote more than once per poll, but please don't. If I believe that someone is voting repeatedly, I will throw out those results, repost the poll, and seriously question that person's priorities.
2) If you want to link to a poll on Twitter / Facebook / your blog / whatever and encourage your friends to come and pump up the support for your favorite plants, you are encouraged to do so.
3) You are also encouraged to leave comments on Rumble posts, if so moved.
4) All photos will enlarge if opened in a separate window/tab.
5) You can choose which plant is "best" according to whatever criteria you decide for yourself. My personal process is a bit convoluted.¹
6) All polls will be open for three days.

Results for matches 1.49-1.52:

In match 1.49, you bastards chose Adenium obesum over Episcia cvv., by a margin of 73 to 44, in what I am forced to conclude was a horribly misguided attempt to upset me. WELL IT DIDN'T WORK! I'M FINE! NOT UPSET AT ALL!²
Match 1.50 was quite close, a lot closer than I expected it would be, but in the end, Zamioculcas zamiifolia scraped together a victory over Alocasia amazonica 'Polly.' The score was 63 to 49.

Adenium and Zamioculcas will throw down in match 2.25, on 13 October.

Ficus benjamina cvv. defeated Begonia rex-cultorum in match 1.51, by a score of 70 to 44.
Finally, match 1.52 looked for a while like it was going to be a blowout -- Haworthia cvv. was at one point getting nearly 81% of the vote against Asplenium nidus / A. antiquum -- but some Asplenium supporters showed up at the last minute and reduced Haworthia's lead. Haworthia still wins, though, 80 to 39.
Ficus benjamina cvv. and Haworthia cvv. go up against one another on 13 October as well, in match 2.26.

And now, we begin round two.

Match 2.1
Clivia miniata cvv. vs. small hybrid Vriesea cvv.

Top: Clivia miniata. (Picture by Guérin Nicolas at Wikimedia Commons.) Bottom: NOID cv.

(All unidentified Vriesea hybrids.)





Match 2.2
Cryptanthus cvv. (earth star) vs. Tradescantia pallida (purple heart)

Clockwise from top left: C. 'Elaine,' C. 'Black Mystic,' NOID, NOID, NOID.

(Both T. pallida.)





Match 2.3
Saintpaulia cvv. (African violet) vs. Echinopsis spp.

Saintpaulia cvv.
Top row, L-R: NOID, assorted NOIDs, NOID.
Middle row, L-R: NOID, NOID, NOID.
Bottom row, L-R: 'Harmony's Red Star,' 'Mellow Magic' close-up, NOID.

Unidentified Echinopsis sp. Probably.





Match 2.4
Epipremnum aureum cvv. (pothos) vs. Crassula ovata/argentea/arborescens (jade plants)

Clockwise from top left: Epipremnum aureum 'Neon,' 'Marble Queen,' 'N'Joy,' trained on a totem.

Clockwise from top left: variegated Crassula ovata, C. ovata 'Gollum,' C. arborescens var. undulatifolia, C. ovata.





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¹ I'm deciding according to a hypothetical situation in which all of my houseplants are gone, as are all the other houseplants of the world, except for one producer/supplier/retailer. Said person is offering to restock me with one or the other of the plants in question but refuses to give me both. Which one would I choose?
² (*sob*)

Rumble Among the Jungle, Matches 1.1-1.4

Rules and Stuff
1) It's probably possible to vote more than once per poll, but please don't. If I believe that someone is voting repeatedly, I will throw out those results, repost the poll, and seriously question that person's priorities.
2) If you want to link to a poll on Twitter / Facebook / your blog / whatever and encourage your friends to come and pump up the support for your favorite plants, you are encouraged to do so.
3) You are also encouraged to leave comments on Rumble posts, if so moved.
4) All photos will enlarge if opened in a separate window/tab.
5) You can choose which plant is "best" according to whatever criteria you decide for yourself. My personal process is a bit convoluted.¹
6) All polls will be open for three days.

Match 1.1
Kalanchoe tomentosa (panda plant) vs. Clivia miniata cvv.

Clockwise from top left: Kalanchoe tomentosa, K. tomentosa flower, K. tomentosa, K. tomentosa 'Chocolate Soldier.'

Top: Clivia miniata. (Picture by Guérin Nicolas at Wikimedia Commons.) Bottom: NOID cv.




Match 1.2
Peperomia obtusifolia cvv. (baby rubber plant) vs. small hybrid Vriesea cvv.

Left: P. obtusifolia 'Golden Gate.' Right top and bottom: P. obtusifolia variegata.

(All unidentified Vriesea hybrids.)




Match 1.3
Ficus elastica (rubber plant) vs. Cryptanthus cvv. (earth star)

Clockwise from top left: F. elastica 'Burgundy,' NOID, 'Tineke' (or some similar cv.), 'Burgundy.'

Clockwise from top left: C. 'Elaine,' C. 'Black Mystic,' NOID, NOID, NOID.




Match 1.4
Yucca guatemalensis (spineless yucca) vs. Tradescantia pallida (purple heart)

Clockwise from top left: Y. guatemalensis, NOID variegated cv., NOID variegated cv., sprouts from cane section cuttings.

(Both T. pallida.)




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¹ I'm deciding according to a hypothetical situation in which all of my houseplants are gone, as are all the other houseplants of the world, except for one producer/supplier/retailer. Said person is offering to restock me with one or the other of the plants in question but refuses to give me both. Which one would I choose?

List: Plants for Terrariums

(Happy Valentine's Day, if applicable.)

This is an odd category to build a list around, because "terrariums," actually, is sort of hard to define. I usually assume, when I hear "terrarium," that we're talking about an enclosed glass container, no bigger than a couple feet in any direction, that's being used to grow moisture-loving plants, but of course there are also extremely large terrariums, terrariums that fit inside an incandescent light bulb, open-topped terrariums, desert terrariums, unplanted terrariums which house animals, etc.

So if you want to get technical about it, there's no plant that couldn't be grown in some kind of terrarium if one is sufficiently flexible about the definition, so the list of "plants for terrariums" equals every plant that exists. Which is an easy answer, but not particularly satisfying.

So what I'm assuming with this list is that we're talking about: an enclosed glass container, no bigger than a couple feet in any direction, that's being used to grow moisture-loving plants. Which means that we're looking for plants that like humidity and moist soil, which grow slowly, and don't need full sun. (Full sun is fine, except that it also comes with quite a bit of heat, and since there's nowhere for heat to escape in an enclosed terrarium, sooner or later an enclosed terrarium in full sun will cook itself to death.)

Which is still a pretty long list, it turns out.

Calathea makoyana. Some Calatheas can get to be large (to at least two feet / 61 cm in diameter) quickly, especially in a terrarium, and large Calathea leaves can block most of the light from reaching plants underneath them, but it's a lot easier to grow a Calathea under glass than it is to grow one on a windowsill.

Cryptanthus NOID. Some varieties can get to be pretty large, but most of the ones I've seen top out at about six inches across (15 cm), and they don't spread like some of the choices on this list will.

Episcia 'Coco.' Happy Episcias will produce plantlets on runners, which should root when they contact the soil (you may need to pin them down gently first, so they're firmly in contact), so they do spread a little, but they stay short.

Fittonia albibenis cvv. are fast-growing, spreading plants. The small-leaved varieties stay very short, while the varieties with larger leaves reach about six inches (15 cm) tall and then bend over under their own weight. The stems root when they touch soil, so over time they'll expand.

Hemigraphis exotica. Can get to be twelve inches (30 cm) tall in good conditions, though usually they're shorter than that.

Hemionitis arifolia. Also to about 12 in / 30 cm tall and about as wide. Mature plants will produce plantlets where the petiole joins the leaf; I'm not sure if they'll bend over and root on their own, or if they have to be helped, but either way, allow a lot of space.

Pellionia pulchra. Fast-growing, aggressive trailing plant in a terrarium. Stays short, but the stems need to be cut back periodically.

Peperomia argyreia. Another somewhat mounding plant that needs about 12 in / 30 cm in height and diameter.

Saintpaulia 'Harmony's Red Star.' I don't know about this variety specifically, but there are many, many Saintpaulia varieties, including miniatures (under 6 in / 15 cm in diameter). (Most get to be larger.) All grow well in terrarium culture, and stay relatively short. Spent flowers do need to be removed regularly, so this may not be the plant for you if you want to plant your terrarium in a narrow-necked bottle.

Soleirolia soleirolii, chartreuse cv. This is another low, mat-forming ground cover. Plants stay short but will spread fairly quickly if not cut back.
Recommends and anti-recommends are more or less pointless here, because what's going to work for you depends on the size of terrarium in question and what you want it to do. If you're interested in planting a terrarium, find out how big the plants you're thinking about including will get before you plant them. You should also try to find out how fast they'll grow: some people like having to get in and prune back the plants every so often, and some people don't.

A few of these plants will also need a more specialized growing medium than ordinary bagged potting mix. Most orchids would like the conditions in a terrarium just fine, but need to be planted in bark instead of potting mix, so I left them off the list.

Not pictured:

• Adiantum capillus-veneris (maidenhair fern)
  
• Aeschynanthus spp. (lipstick plants, goldfish plants)
  
• Asplenium antiquum (birds-nest fern)
  
• Asplenium 'Austral Gem'
• Asplenium nidus (birds-nest fern)
  
• Begonia rex-cultorum cvv. and small rhizomatous Begonias. I personally wouldn't try to grow a rex begonia outside of a terrarium.
  
• Blechnum brasiliense (tree fern) and other tree ferns
  
• Most Calathea spp. are suitable, at least when younger
  
• Chamaedorea elegans (parlor palm)
  
• Codiaeum variegatum cvv.
• Columnea cvv.
• Cryptbergia cvv.
• Cyanotis kewensis (teddy bear vine)
• Cyrtomium falcatum (holly fern)
• Davallia spp. (rabbit's-foot fern)
  
• Didymochlaena truncatula (mahogany fern)
• Dionaea muscipula (venus flytrap), though they have fairly specific temperature and water-quality needs which won't necessarily mesh with other plant species
• Epipremnum aureum (pothos)
• Ficus pumila (creeping fig)
  
• Some of the smaller Guzmania cvv.
• Hypoestes phyllostachya (polka-dot plant)
• Ludisia discolor (jewel orchid) and the other jewel orchids like Macodes and Goodyera spp.
  
• Maranta leuconeura cvv. (prayer plant)
• Nematanthus cvv. (guppy plant)
• Some of the smaller Neoregelia cvv.
• Nephrolepis exaltata cvv. (Boston fern)
• Pellaea rotundifolia (button fern)
• Peperomia caperata
• Peperomia clusiifolia
• Peperomia glabella
  
• Peperomia griseo-argentea
• Peperomia obtusifolia cvv. (baby rubber plant)
  
• Peperomia orba
• Peperomia verschaffeltii
• Some self-heading Philodendron hybrids, especially 'Autumn,' 'Moonlight,' and 'Prince of Orange'
• Philodendron brandtianum
• Philodendron hederaceum cvv. (heart-leaf philodendron)
  
• Pilea cadierei (aluminum plant)
  
• Pilea depressa (baby toes)
  
• Pilea involucrata cvv. (friendship plant)
  
• Pilea microphylla
  
• Pilea mollis 'Moon Valley'
• Pilea nummularifolia
• Pilea peperomioides? (Chinese money plant, missionary plant)
  
• Plectranthus oertendahlii?
• Podocarpus macrophyllus (Buddhist pine)
  
• Polypodium formosanum
• Polypodium grandiceps (elkhorn fern)
• Polyscias fruticosa cvv. (ming aralia, parsley aralia)
• Pteris cretica cvv. (table fern, Cretan brake)
• Saxifraga stolonifera (strawberry begonia)
• It seems to me like Schlumbergera cvv. (Christmas cactus, holiday cactus) ought to work, though I can't say I've seen it attempted much.
• Scindapsus pictus (silver pothos)
• Scyphularia pycnocarpa (possum tail fern)
• Selaginella spp. (spikemoss)
• Miniature Sinningia cvv. (gloxinia)
• Smaller Spathiphyllum cvv. (peace lily)
• Streptocapus saxorum (streptocarpella)
• Streptocarpus cvv. (cape primrose)
• Stromanthe spp.
• Syngonium podophyllum (arrowhead vine)
  
• Syngonium wendlandii
  
• Tillandsia cyanea and other Tillandsia spp. (pink quill, air plants)
  
• Tolmiea menziesii (piggyback plant)
  
• Tradescantia spathacea? (moses in the cradle, oyster plant)
  
• Vanilla planifolia? (vanilla orchid)
• Small Vriesea cvv.