Flora
The planets in Astroneer contain a large variety of flora, from dangerous flora to flora that aids in progression. They vary in shape, size, and color, and are found on all planets.
Hostile Flora
Hostile Flora are types of hazardous flora that harms, and in some cases, kills the player. Flora grow on each planet, with some flora only showing up on certain planets, such as the varieties of Attactus only found on Calidor or Atrox. Players will need to be more careful the deeper they go into a planet, with more dangerous flora being around the corner. To destroy Hostile Flora, use the Terrain Tool to uproot them. After destroying the flora, they may drop 1 to 3 Research Samples, some Seeds, or reveal a Research Item buried underneath.
Defensive Flora
Defensive flora only harms the players when approaching or jumping onto the plant, typically knocking back the player and causing initial damage. If the player gets knocked too high, the player may take fall damage and die. Defensive flora has a chance when dug up to drop a seed, allowing it to be replanted to gain even more Seeds, Research Samples or Research Items at the roots.
Popcoral
Popcoral are a generally amorphous purple plant with red polyps and can be found in abundance in caves. They are generally harmless; however, once uprooted with the Terrain Tool, they will explode, revealing their true nature. This explosion can be fatal if a player is standing too close, but they can be safely dug up from a distance.
The old appearance of Popcoral
A colony of Popcoral, along with a seed
A solitary Popcoral with no background
Daggeroot
Daggeroot are a light lavender plant with red spots, found mostly on Desolo, on the surface of Atrox, and in the mantle layer of Sylva, and pose an extreme danger to the player. Getting too close to the Daggeroot will cause them to release dangerous spikes around them to stab the player, which can very easily kill the player in only two hits. This is the only hazardous plant to be in its original form since before the 1.0 update and was also the only plant that could be planted before then.
A Daggeroot colony
A solitary Daggeroot with no background
Wheezeweed
Wheezeweeds are big, round, yellow plants with holes revealing a red membrane found on Atrox and Calidor. When the player approaches them, they produce a wheezing sound, and the membrane begins to puff out through the holes. If the player gets too close, they rapidly puff up, knocking the player back a good distance.
A planted Wheezeweed
A solitary Wheezeweed with no background
Spinelily
Spinelilies are spiky lilypads that can form in small clusters, found on Calidor and Atrox. When a player steps on them, it will launch them in the air and may cause damage if launched too high.
A planted Spinelily
A solitary Spinelily with no background
Lashleaf
Lashleaves are flora with two leaves with a pink tongue-like leaf in the middle, found on Vesania and Novus. When the player steps on one, it will launch them into the air extremely high, potentially causing lethal fall damage. Domestic Lashleaves will rotate 90 degrees counter-clockwise when they are finished growing.
A solitary Lashleaf with no background
Bouncevine
Bouncevines are green plants with red vines, found on the surface of Sylva. When stepped on, the player is launched up in the air, albeit not very high. Since they are most prominent in the mountains, the player could be launched high enough to be killed by fall damage, though unlikely.
A solitary Bouncevine with no background
Thistlewhip
Thistlewhips are plants that have a purple base with a long orange vine with a bulbous end, found on Vesania and Novus. When approached, the vine will shake and produce pollen as a warning. Should the player move closer, it will whip at the player with the vine, knocking them away and dealing moderate damage.
A solitary Thistlewhip with no background
Lashvine
Lashvines are flora that spawn on the surface of Sylva, Calidor, and Atrox, exclusively in rings surrounding a Cauldrangea. These were added to the game in the BOO Update, and are seasonal to the EXO F.A.R.M. event. They attack the player in a similar manner to Thistlewhip, however, they deal more damage and knock the player back considerably further. Paired with the volatile Attacti that also spawn, they can be very deadly if the player is not careful. Lashvine are the only plants that do not produce a seed or research samples when dug up, making them impossible to grow by the player.
A Lashvine on Atrox
Offensive Flora
Offensive flora typically have a larger range of attacks and are more deadly than defensive flora, such as shooting projectiles or spraying clouds of acid.
Volatile Cataplants and Volatile Attacti produce explosions, which can be used to break open EXO Caches without Dynamite.
Hissbine
Hissbines are green, coiled flora with a row of "holes" lining them, which occasionally emit harmless puffs of green gas. They generate underground on all planets. When approached, a Hissbine will emit a sluggish, homing cloud of acid at the player. There are three varieties: Normal, Vibrant, and Dull. The acid clouds from these varieties deal different amounts of damage, with Normal Hissbines being the least deadly, and Dull being the most dangerous. More difficult planets have more dangerous Hissbines. They function similarly to the "acid pot" flora that existed before Patch 1.0.
A Normal Hissbine
Boomalloon
Boomalloons are flora that generates on the surface and caves of Glacio. If the player gets too close, they explode with a cloud of acid. They are relatively similar to Popcoral, but these only require the player to be nearby to explode. They have a hitbox that is used to detect if the player is close enough for it to explode, but this hitbox has some rather strange properties. The hitbox will prevent players from interacting with things in it such as scanning Research Samples, or dropping items in it. Boomalloons can be detonated safely simply by approaching them slowly, as their trigger radius is bigger than their blast radius. Boomalloon seeds take roughly a minute and 20 seconds to grow.
An undisturbed Boomalloon
Cataplant
Cataplants are flora that have an appendage holding a red orb, with the base being colored depending on the variety. If the player gets in range, it will begin quickly forcing a bubble of air through its base to the end, lobbing the red orb at the player. After a couple of seconds, the orb will then explode, making a cloud of gas if it is a Noxious Cataplant, and causing a dangerous explosion if it is a Volatile Cataplant. The Cataplant will continue throwing orbs until the player moves away or is dead. Such orbs sometimes will clip through the terrain or deflect off slopes, rendering the player safe from the attack. Noxious Cataplants can be found on the surfaces and caves of Vesania and Novus, while Volatile Cataplants can be found on Glacio in groups of up to three. If the Volatile Cataplants kill you, some of your items may be destroyed.
Volatile Cataplants can be tricked into destroying themselves, and can also be exploited to break EXO Caches.
An inactive Noxious Cataplant
Attactus
Attacti, plural of Attactus, are flora that generate on the surface and underground, with Spiny Attacti generating on Calidor and Volatile Attacti on Atrox. If the player gets in range, it will activate and start spitting deadly projectiles at the player. When the projectile collides with terrain, it will harmlessly "piff" if it is a Spiny Attactus, or give a small explosion and destroy a small portion of soil if it is a Volatile Attactus. The explosion from a Volatile Attactus can also destroy players' vehicles, making Volatile Attacti quite dangerous for rovers or shuttles.
An inactive Volatile Attactus
Spewflower
Elegant and Noxious Spewflowers are flora that respectively generate on the surface and underground of Atrox. When approached by the player, they will immediately retract their umbrella-shaped leaf and begin to spew a cloud of poison in a radius until the player dies or moves away from the plant. The player may stand on the edge of the poison cloud to observe the Spewflower in action. The poison clouds from Noxious Spewflowers do considerably more damage than those from Elegant Spewflowers.
An undisturbed Elegant Spewflower
An Elegant Spewflower spewing poison
A Noxious Spewflower blooms deep underground
Tappable Flora
Tappable flora is flora that is used to obtain 
Organic with the use of the 
Tapper. They can be found on various planets and can be harvested for seeds to be grown anywhere. All Flora can be tapped, but unlike Offensive and Defensive flora, the Tappable sort are harmless and easily harvested without having to dig up a hostile plant first. Tappable flora resemble common vegetation, but are distinguished by large flowers of Organic.
From left to right: Honeypot, Stretchpetal, Pricklepod, Cactile and Plumefir
Plumefir
Tall, elegant tree found in Sylva's forests.
A solitary Plumefir with no background
Cactile
Branched cactus found rarely in Calidor's deserts.
A solitary Cactile with no background
Pricklepod
Spiky barrel cactus found in Glacio's thermal valleys.
A solitary Pricklepod with no background
Stretchpetal
Slim, quaking tree found in Vesania's forests. Novus has trees which look similar, but no genuine Stretchpetal.
A solitary Stretchpetal with no background
Honeypot
Low-growing pitcher plant found on Atrox's plains. This is the most productive Tappable plant.
A solitary Honeypot with no background
Spookysquash / Sturdysquash
Gnarled Spookysquash were pumpkin-like flora that could be found on Vesania and Atrox during the EXO Biofuel Obtainment Operation LTE, and dropped seeds for the other five varieties when dug up. When planted they can grow into a Round, Mutated, Smiling, Stunted, or Astro Spookysquash. The type of seed determines the variety grown. However, for the EXO F.A.R.M. event, wild Sturdysquash could be found instead, whose seeds could produce Round, Knobbly, Plump, or Curious Studysquash.
Mutant Flora
All offensive flora will drop mutated Seeds that allow the player to grow versions of the flora that will not attack the player. The red markings typically found on hazardous flora are replaced with light blue. Some mutant seeds are also the favorite foods of galastropods, increasing their buff from 10 to 30 minutes.
A solitary Mutant Hissbine with no background
A solitary Mutant Boomalloon with no background
A solitary Mutant Noxious Cataplant with no background
A solitary Mutant Volatile Cataplant with no background
A solitary Mutant Spiny Attactus with no background
A solitary Mutant Volatile Attactus with no background
A solitary Mutant Elegant Spewflower with no background
A solitary Mutant Noxious Spewflower with no background
Other Flora
Aside from hazardous flora, there are types of flora that can be found almost anywhere, such as the grass on Sylva. Most of these plants will provide the player with Organic when dug up, although others generate Research Samples. In this case, they do not provide organic but can reveal a research item if dug up. If the player is careful, they can dig up enough ground around the research item to pick it up without destroying the plant.
Trivia
The names of most flora consist of a portmanteau of their defense/attack mechanism and a plant term.