Warning: contains major spoilers for Shang-Chi Infinity Comic #3!
For years, DC has had Poison Ivy as a major villain and now, Marvel has just introduced their own toxic botanist. Shang-Chi Infinity Comic #3 fully introduces and reveals the origin story of Jessa Chen, also known as Doctor Gelsemium. While she appeared in the first two issues, the third issue provides the basis for her villainous behavior and identity.
Marvel and DC often have parallel heroes and villains, with numerous characters sharing similar powers. Poison Ivy debuted in 1966, but Marvel hasn't really had a directly parallel character to her - until now. The closest Marvel character would have likely been Plantman, though he debuted three years before Ivy and reformed from villainy. However, he never garnered the same level of popularity.
Shang-Chi Infinity Comic #3 has the creative team of Alyssa Wong, Nathan Stockman, Tríona Farrell, and VC's Joe Sabino. Within this series, Shang-Chi, White Fox, and Leiko Wu are facing a botanical threat. A bioweapon has been released in the world that is turning people into plants. The source of this threat is Doctor Gelsemium - the codename of Jessa Chen: a scientist who initially tried to do good things, but has significantly lost her way. Shang-Chi has his hands full.
Doctor Gelsemium is a researcher who was trying to use toxic plants to manage chronic pain. While a specific condition is not revealed, it is shown that Chen herself suffers from chronic pain in her hand. Her experiments ultimately affect cell growth and she used herself as a test subject. This experimentation resulted in her growing a botanical arm in place of her own. She can manipulate her arm and turn other people into plants by using the toxic gas she developed. Like Ivy, Gelsemium is revealed to like the company of plants better than people.
Much like Poison Ivy is named after a toxic plant, so is Doctor Gelsemium. Gelsemium is her "favorite genus of toxic plant," though it isn't as well-known as some other toxic plants. This villain is very similar to not just Poison Ivy, but also Dr. Curt Connors - aka the Lizard. Like Connors, Gelsemium was trying to facilitate cell growth to heal her own appendage. Unfortunately self-testing never seems to work out well in comics. This character's longevity in comics is unknown at present, but she has a direct connection to Shang-Chi since she worked for his father. Doctor Gelsemium could have a chance to become a regular villain for Shang-Chi and his associates now that Shang-Chi has debuted in the MCU. Marvel is certainly lacking villains that have control over botanical elements, despite having heroes like the Guardians of the Galaxy's Groot and the Runaways' Klara Prast. There is definitely room for Marvel to develop their own iteration of Poison Ivy.