The term “house keltza” designates all species of big plants that are used as live structures for buildings and general infractructures.
Blue keltza are the most commonly used variety of house keltza. A young mature blue keltza will be about 5m high with a cap of 3m diameter, while the oldest caps can reach 20m high, with several caps up to 6m diameter.
Blue keltza can be found in nature, but most are found in somatei cities. Wild varieties are notably smaller and typically have up to two caps only. Domestic blue keltza grow much bigger and live longer, to the point they are sometimes considered their own variety, with a truly symbiotic relationship with somatei society.
As a matter of fact, while wild keltza caps drip with orange, bioluminescent soma aimed to be eaten and transported by animals (which used to include primal somatei!), domestic keltza’s soma remains stuck to the cap and only falls when dry.
To plant a new keltza, somatei actively scrape soma from different caps into a bag that then gets planted in an open area. The new shoot is regularly watered and taken care of until it reaches a height sufficient to build a house underneath.
In the meanwhile, young keltza are often used as temporary gathering places. If placed along a path, a bench can be installed underneath.
Red keltza are incredibly tall, tick and robust. They naturally grow alongside cliffs, from the top part.
Young red keltza manifest as a bulb that grows many tentacle-like vines looking for a drop. Once one is found, growth is focused in its direction and one tentacle grows down it until it reached the bottom. Then, it takes root and starts thickening until becoming a thick trunk up to 5m of diameter.
Red keltza have always been used to help climbing cliffs and are now used as the main pillar for stairs and elevators.
Building on red keltza takes very specific expertise, as contact with its sap causes skin irritation and can cause permanent damage to a Somatei’s eyes. As a consequence, structures are never bolted or really affixed to the keltza but always built so that leaning on it provides sufficient stability.
Red keltza produce soma through holes evenly distributed on its trunk. Each hole stands above a huge, stubby thorn that curves upward. The thorns are sometimes used to help stabilise structures, but they are not especially sturdy.
Milecoteltza, or lover keltza, are a very particular species that is sometimes used as roof instead of a blue keltza. Its advantage (and disadvantage both) is that the size of the resulting structure is set when the keltza is planted. The resulting roof is lower and larger than a blue keltza’s.
Milecoteltza’s particularity is that they need two (or more) specimens to be planted nearby to be viable. While sprouting, milecoteltza will grow probing vines looking for a partner. Once one is found, the touching vines fuse while the others are resorbed into the bulb. The sprouts then start growing towards another all while dividing into branches that then intertwine with the other keltza’s, forming a flat net. This net stands at about 4m at maturity. This net will then support soma pockets that grow intertwined bulbs. When bulbs are scattered, they separate into 2 so that the two resulting keltza can form a new net while growing.