Externally Tvekna appear to be trees much like any other, although recognisably of no natural tree species. Internally they are very different from unmodified trees. The rudimentary nervous system of a normal plant has been expanded and modified to provide a level of mental processing power equivalent to that of a baseline human, spread over a large number of ganglia throughout the tree. In addition to this, the normal senses of touch and the chemical senses of the unmodified plant have been retained and indeed enhanced in the Tvekna; their sense of smell is their primary sense. Certain of the sensory hairs that cover the leaves of the Tvekna have been modified to detect sound. Also, vegetable forms of a single element of an insect's compound eye have been engineered into the Tvekna, and dot the veins of its leaves, providing all-round vision, although with rather low resolution.
They also have a highly developed system of chemical defence, adapted from all of the chemical defences used in unmodified plants. Chemical defences and poisons allow them to prevent unwanted plants and animals from intruding on their space, and kill any existing plants in areas they wish to grow into, while also nourishing plants and animals they wish to encourage. This provides a means by which each Tvekna can manipulate the environment in their vicinity.
Unlike the Alseid the Tvekna cannot move other than as unmodified plants move, and they do not live socially. Instead individual Tvekna are scattered across their worlds in a variety of environments.
Despite this, they do have a society of sorts, and are not solipsists. Each individual Tvekna speaks by releasing vast numbers of 'data spores', light wind-carried packages of stored data, which then drift far and wide across the world, subject to the vagaries of the weather. Other Tvekna automatically trap and read these data spores, thus learning what the other Tvekna chooses to say. Thus there is a society of constant speaking and hearing, but with no conversations, as such, and usually quite a slow rate of sending and response. Everyone is listening all the time, and can choose to talk, but not who they talk to or when they will be heard.
Tvekna reproduce is a much more indiscriminate manner than the Alseid. Hermaphroditic and using wind pollination, they scatter huge numbers of tiny wind-carried seeds into the air. These scatter into the world. Most of the seeds are lost, but a few will take root and grow. Those that eventually grow large enough will begin to pick up data spores from the adult Tvekna, and begin to learn. This is helped by the fact that all Tvekna constantly produce 'education spores' (and cannot not produce them), which are ignored by adults but provide young Tvekna with the knowledge they require to mentally develop and mature into adults. There are cases where Tvekna are found only half-educated, or even utterly uneducated, due to having grown in a position which limits their access to the data spores of other Tvekna, but this is very rare.
The Tvekna are by and large talkative but unsympathetic. They cannot do anything to help others, so they do not worry about it. They do like to know things and are, in their way, terrible gossips. They do not feel loneliness as humans might experience it, but will worry if they lose contact with other Alseid. There is not a Tvekna economy as such; in most cases the bartering of news and so on for more news and other information is as far as their economy extends.
Most Prim and Ludd Tvekna simply talk about things affecting them directly, such as the weather, problems, changes around them, what they have heard from others, in a form essentially rather like a weblog. The more artistically-inclined Tvekna also produce song, stories and poetry that they send out into the world. Higher technology Tvekna often user higher technology linkages to talk amongst themselves, and talk about more abstract topics, such as the theoretical sciences, mathematics, philosophy and the like. Scientific types may well have remote drones allowing them to manipulate objects around them, and perhaps also access to remote sensors, such as the telescopes and so on that they need for their work.