Quercus novis, a tweaked oak tree species growing on Garrow, a partially terraformed colony in the Outer Volumes. Such plants help to stabilise the soil and maintain the oxygen balance.
In the strictest sense plants are any of a major group of related Old Earth organisms that are multicellular, eukaryotic, exhibit embryonic development and, except in a few parasitic forms, capable of photosynthesis via chloroplasts that bear chlorophylls a and b that give them their characteristic green colour. They are the primary producers in all of the terrestrial and many of the shallow aquatic ecosystems of their native planet.
More broadly, a plant is any biological organism, Terragen or otherwise, and natural or otherwise, that is sessile and photosynthetic. Naturally evolved Terragen algae and their gengineered descendants may be called plants. Plant-like xenobiota, neogen, synano or cyborg organisms, particularly sessile and/or photosynthetic examples are often called plants as well. Inorganic beings like plantbots are called plants only by analogy.
Some xenologists and biologists prefer to reserve the term 'plant' exclusively for Terragen species which are members of the Kingdom Plantae, and invent alternative terms for other life forms, such as 'plant-like organism', 'plant analog', or 'plantoid'; others extend the classification 'plant' to cover similar xenobiont equivalents. There are similar disagreements regarding the nomenclature for sentient but subsophont neogen, synano, and cyborg organisms that resemble natural Terragen plants.
Terragen plants are distinguished from the green algae that gave rise to them by embryological development and complex tissues, including reproductive organs that they evolved in adapting themselves for life out of the water. Though they lack the morphological and behavioural complexity of animals, plants are biochemically diverse; able to produce a wide variety of organic compounds. Plants comparable to mosses and liverworts first appeared in the late Ordovician, and colonized wet areas during the Silurian; by the late Devonian they had evolved the full suite of features necessary for life on land, and formed the first forests. Initially, lycopods, sphenophytes, and various ferns were predominant, but seed-bearing plants such as the cycads, gingkoes, conifers, gnetophytes, and angiosperms eventually came to dominate the flora. The angiosperms, or flowering plants, became common over the course of the Cretaceous, and accounted for the vast majority of species thereafter.
Lazurogenic projects have created reasonable facsimiles of most major extinct Terragen plants, though because of the fragmentary nature of plant fossils there is a large component of extrapolation and imagination in their re-creation. Still, groves or entire forests of cordaites, lepidodendrons, bennettites, glossopterids, calamites, and various extinct cycads, conifers, and gingkoes are quite common today. Plants both baseline and gengineered play a very large role in agriculture, hab maintenance, and terraforming. In the case of dyson trees and orwoods, the plants are themselves the habitat. Plant provolves are relatively rare, due to the constraints of powering a sapient-level thought process exclusively from the energy that can be gathered from photosynthesis at a single site (see bradychronic plant provolves), but there have been a number of work-arounds for this problem as seen in such groups as the Alseids, Clade Keruing, or Dendrosequoia Sapiens.
Angiosperm - Text by M. Alan Kazlev In Terragen biology, a flowering plant in which the seeds are enclosed within an ovary which ripens into a fruit. Angiosperms are still the dominant type of terragen plant, with an estimated 250,000 baseline species, and literally hundreds of millions of neogen species. Their flowers are used in reproduction. Angiosperms evolved 125 million years ago, during the early Cretaceous period.
Autotroph - Text by M. Alan Kazlev An organism that produces its own food from light or chemical energy and/or inorganic matter. Also called a Producer (or Primary Producer). Among terragen life forms, most green plants, many protists, and many prokaryotes are autotrophs. There are also alife and informational autotrophs/producers. Every food chain rests on autotrophs. Autotrophs in turn provide food for heterotrophs.
Dendrosequoia sapiens - Text by Steve Bowers 150 meter high sophont trees with biocomputronium cores; developed in the Biopolity and have spread to many worlds. Revered as spiritual leaders in some parts of the Sophic League.
Epiphyte - Text by M. Alan Kazlev A plant (or sometimes other organism) that lives attached to a larger plant or a structure like a tower or a building. Epiphytes acquire water and nutrients from the air.
Ethnobotany - Text by M. Alan Kazlev Study of how plants are used in various (mostly prim, neo-prim, or bioborg) hu, tweak, splice, provolve, and xenosophont cultures.
Forest - Text by M. Alan Kazlev Any biome type involving a dense concentration of trees or analogous neogens or xenophyta, distributed over a large area of land. In some biomes, such as rainforest, there are a number of distinct levels, such as canopy and forest floor, each with their distinct micro-ecologies.
Forest Floor - Text by M. Alan Kazlev The lowest layer of a rainforest, extending from the ground to about a meter in height. This layer is teeming with animal life, including insects, mammals, and ground birds.
Gymnosperm - Text by M. Alan Kazlev and Stephen Inniss Terragen seed-bearing plants in which the seeds develop without a protective covering derived from the ovaries. In short, any seed-bearing plant that is not an angiosperm. They release pollen into the air to the female ovule, causing fertilization. Gymnosperms include seed ferns, conifers, ginkgoes, and cycads. Conifers were the only common gymnosperms by the time humanity arose on Old Earth, but many other kinds of gymnosperm have since been lazurogened.
Plastid - Text by M. Alan Kazlev A cell-body (organelle) found in Terragen plants and algae. In plants, any type of plastid can transform into another, making them popular among some gengineers. Their shape and function differs. For example, proplastids develop into leukoplasts which develop to chloroplasts and/or chromoplasts for photosynthesis. They have their own DNA (ctDNA) and ribosomes due to their origin as symbiotic cyanobacteria.