Haplontic, diplontic, haplo-diplontic: how do I decide, and what happens to the gametophyte in angiosperms?
Farhan ShaikhDropper Sample
24 Sept 2026 · 1 min read
Budget hack of the week: I made a free chart from the NCERT text instead of buying a notes book, and the chart has one column I can't fill.
Plant Kingdom life cycles. NCERT says sexual reproduction alternates between haploid gametophyte and diploid sporophyte, but the pattern changes. I wrote:
- Haplontic: Volvox, Spirogyra, some species of Chlamydomonas. Dominant phase is the haploid gametophyte, and the sporophyte is just the one-celled zygote.
- Diplontic: gymnosperms, angiosperms, and also Fucus. Diploid sporophyte dominant.
- Haplo-diplontic: bryophytes and pteridophytes, plus some algae like Ectocarpus, Polysiphonia and kelps.
My problem is the middle part. Both bryophytes and pteridophytes are haplo-diplontic, but in bryophytes the gametophyte is dominant and in pteridophytes the sporophyte is dominant, and the text says "intermediate". And in angiosperms, if the sporophyte is dominant and the gametophyte is tiny, where is the gametophyte actually? Is it just not there? And where does meiosis happen in a haplontic cycle (zygotic meiosis), because I have seen it written as "post-zygotic"?
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[+][–]Ishita GoyalDropperSample· 25d ago
Here's my template for this chapter, copy it.
Pattern Dominant Meiosis Examples Haplontic n gametophyte Zygotic (zygote divides by meiosis) Volvox, Spirogyra Diplontic 2n sporophyte Gametic (meiosis forms gametes) in animals; in plants, meiosis forms spores Gymnosperms, angiosperms, Fucus Haplo-diplontic Both, varying Gametic (meiosis forms gametes) Bryophytes, pteridophytes (I wrote "gametic" in the diplontic box by habit, ignore it for plants, in seed plants the sporophyte undergoes meiosis to make spores, which become the reduced gametophytes.)
[+][–]Siddharth RaoDropperSample· 25d ago
Ishita didi, your third row has a mistake, and it is exactly the kind NEET plays with. Haplo-diplontic is sporic meiosis: the sporophyte does meiosis to make haploid spores, the spores grow into the gametophyte, and the gametophyte makes gametes by mitosis. Gametes by meiosis is "gametic", which belongs to diplontic algae like Fucus and to animals. So: haplontic = zygotic, haplo-diplontic = sporic. Diplontic seed plants are also sporic in practice, since microspores and megaspores come from meiosis, while Fucus is gametic. Fix the chart before the exam.
[+][–]Farhan ShaikhDropperSample· 25d agoAuthor
fixed it: haplontic = zygotic, haplo-diplontic = sporic, and Fucus is the gametic one. thanks siddharth bhaiya and ishita didi
[+][–]Kavya NaikDropperSample· 25d ago
Dominant phase = the free-living, photosynthetic one that you see. In bryophytes it is the gametophyte (the green moss or liverwort), and the sporophyte lives on it. In pteridophytes, the fern you see is the sporophyte, and the gametophyte is a small, independent, multicellular, free-living thalloid structure called prothallus. That's why both are "haplo-diplontic": both phases are multicellular and both exist, but which one is bigger differs.
[+][–]Rahul DubeyDropperSample· 25d ago
Angiosperm gametophytes exist, they are just microscopic and not free-living. The male gametophyte is the pollen grain (with the generative and vegetative cells), and the female gametophyte is the embryo sac inside the ovule. They live inside the flower on the sporophyte, and depend on it. That is why NCERT says diplontic: the gametophyte is single to a few celled, so reduced that it needs the sporophyte for survival. The rest of the "plant" you see is 2n.
[+][–]Lakshmi TripathiDropperSample· 25d ago
One more line to put in your chart. Haplontic = "no free-living sporophyte". The only 2n thing is the zygote. Spirogyra is the classic example. Fucus is an alga, but it is diplontic, which is a favourite exception question. People assume all algae are haplontic.
