In an half-time semi-arid, half-time watery forest region, lives the Crown chalice plant. It generally stands from the middle to the top of tall and wide trees, a mix between Deane's gum eucalyptus and Corylus colurna hazelnut trees. In other words trees ranging from around 25 to 40m in height, with some good amount of branches.

What's interesting about this plant is that in order to sustain itself, it not only takes the sunlight and water that fall on it, it also lives in symbiosis with its tree and the animals resting or drinking in it. Yes, because the Crown chalice acts as a natural anti-bacteria water container, nurishing its host and fellow companions with healthy, fungus free water. In exchange, it gets a nice complement to its diet with some minerals from the tree and bits of lost animal parts.


My question's relatively simple in concept : How much water at most could the crown chalice plant be able to hold, before it crumbles on itself and the tree? In other terms, what would be the highest expected Chalice scale I could go with, on average?

My goal here is to know how far we can stretch things out roughly before it becomes too much unbelievable and unrealistic. Indeed, while my world is not 100% accurate on digits, I still use some concepts to draw the tips of the universe, and I don't want to be too scientifically incoherent There are many factors to take into account, so I'll try to sort the most I could think off to win some time.

Crown chalice characteristics

We will presume the tree is already big and old enough and reached an "adult" or old age, and that there is no issue keeping the chalice full (it is not the question). Also, we can consider the chalice global resistance, hardness, mass and density to be up to the host tree branches and leaves themselves. Since I'm not fully aware of tree physics and don't have an answer to the capacity liming factors, I let you choose whether getting inspiration from old big branches or younger and smaller ones.

Since the plant does not pop up instantly like some mine 'n crafty games, I'll talk about how it grows and its final rough shape and location. It's particularly important because I have some doubts on whichever grants the best capacity. When "attaching" to its host, there are actually two possibles situations :

  • The seed sits on one branch only, which we'll call the "single-branch" setup : A single vine wraps around the branch, then another spurts and start hanging, creating an evergrowing hanging basket below the branch.
  • More rarely the seed gets at the junction between two branches, which, you guessed it, will be called "dual-branch" setup : Starting from the junction, the plants grow wines around the two branches, and as it goes a "hammock" to contain the water is made in-between.

The Crown chalice gets a hang on the tree during the arid season, so it's unlikely to break apart while it is empty, since, well, it doesn't bear such an high mass of water. Also, while there is some tolerance, chalices don't grow effectively on branches which bend too much, indeed, dual-branch setups spill the water out of the holding bowl (it's hardly horizontal), and single branch configurations get dropped off the tree as the wines tend to lose a good grip around the base.

Prior researches and hypothesis

Most probably, the single-branch setup will hold less liquid as its two-branch counterpart, as there are one less point to hold water in place and it might be more constrained horizontally.. Though... We'd also need to consider the fact that two-branch setups causes some sort of horizontal force to the tree, since the ropes are not directly above the container. Alas, I don't know how much that'll influence the results, and I don't have a tree I can tear its branches off to check (that'll make my neighbour angry, and the tree very sad).

All in all, while I think I have some basic understanding of the constraints such structure would have, I'm stucky-stuck because I lack key data regarding wood resistance and equations to make any kind of wild guess. For instance, I know that 10kg condors can stand relatively easily on tree tops, but it doesn't tell me how far this weight can be pushed up, nor if standing on top is similar or totally different to hanging at the bottom or sideways.

So how far can I reasonably ramp up the water holding capacity of the Crown Chalice plant?


1 Answer 1


You have invented the tank bromeliad.

tank bromeliad


Tank bromeliads have leaves that form a reservoir to hold water at their bases, with the largest bromeliads holding up to two gallons of water.

So two gallons is the upper limit for extant epiphytic plants that have a water tank. These tanks are super cool and things do live in them an use them. My favorite is the arboreal frog which has a single tank living tadpole, fed by its mother on eggs laid for the purpose.

  • $\begingroup$ Bromeliads are epiphytes, though: they just use the trees for support. An interesting variant in a semi-arid area would have it become a "water parasite" on the host tree, which has a deep root system able to obtain groundwater in the dry season. $\endgroup$
    – jamesqf
    May 21, 2021 at 4:25
  • 1
    $\begingroup$ I'm surprised that this plant is not in my exotic vegetation book, glad you found it! I thought it would be able to hold a little more than - let me check - 7,5 liters (I'm not used to imperial units x_x). Maybe it's because there is much more weight than the water itself : leaves, the base, etc. Or maybe it's because if it grows on average much bigger, a lot of bromeliads would fall out and apart. A selective evolution, sort of. $\endgroup$ May 22, 2021 at 13:08

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