Gemmae are present in :

The correct answer is Some Liverworts.

Step-by-Step Explanation:

1. What are Gemmae?
Gemmae (singular: gemma) are specialized, multicellular, asexual reproductive structures. They are green, haploid, and bud-like structures that develop in small receptacles called gemma cups.

2. Occurrence in the Plant Kingdom:
Gemmae are characteristic features of certain bryophytes, specifically liverworts. A well-known example of a liverwort that produces gemmae is Marchantia.

3. Mechanism of Reproduction:
When the gemmae mature, they detach from the parent body and germinate to form new individual thalli (gametophytes). Since this process does not involve the fusion of gametes, it is a form of vegetative or asexual reproduction.

4. Evaluating the Options:
- Mosses: Mosses typically reproduce vegetatively by fragmentation and budding in the secondary protonema, not via gemmae.
- Pteridophytes: They reproduce mainly via spores and do not possess gemma cups or gemmae.
- Gymnosperms: These are seed-producing plants and do not form gemmae.
- Some Liverworts: As established, gemmae are key asexual reproductive bodies found on the thallus of liverworts like Marchantia.