Bud vs bloom phenology on "tricky" plants

General
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In annotating flowering phenology for a project I frequently come across some cases where I wonder how they should be annotated. I’m sure some of these may have cropped up in discussions before but I can’t find all of those comments, so trying to collect some more in this thread. What is the best way to handle annotating e.g. the following?

  1. Dormant flower buds on woody perennials: Some plants (e.g. rhododendron) make next years’ flower buds pretty soon after they’re done blooming for the current year. Those buds stay dormant through the winter until the next blooming season. I’ve seen comments in the past that we shouldn’t annotate them as flower buds until “bud break” when they start showing petals emerging. However, I find myself increasingly wanting to annotate all of them, even in their dormant state, because (a) they provide useful clues for species identification and I would like to be able to sort for them in Identify mode, and (b) how are less botanically knowledgeable people even supposed to know the distinction between a “dormant” bud that shouldn’t be annotated and a “close-to-flowering” bud that should be annotated? Not annotating them seems like a recipe for inconsistency as more people discover and use annotations.

  2. Budding/flowering stages for plants that hide their reproductive parts: Examples for this are spadix/spathe inflorescences (e.g. Jack-in-the-pulpits and skunk cabbage), which might even require cutting them open to see if the flowers at the base of the spadix are actually open or not. Very few observers do that and in many locations it would be illegal to mess with the plants in such a way without a permit anyway. I see these being annotated as blooming for another project as soon as the spathe opens to allow access for pollinators. Is that a good way to handle it, at least for iNat purposes, to keep things consistent?

  3. Budding/flowering stages for flowers that never fully open: Some plants keep their flowers seemingly closed throughout the entire existence of that flower. Some of these are cleistogamous (self-pollinating), others like Bottle Gentian do attract pollinators capable of forcing their way into the flowers for nectar and pollen. Because it is so hard to tell budding vs. flowering in these based on pictures, I’ve been annotating them pretty much all as flowering, assuming they are ready for pollination and to get them to show up in the project I’m working on, which aims at identifying the best time/location for wildflower hikes. We can only choose one phenology stage for collection projects, and annotating as “budding” would mean they would be excluded.

  4. Budding/flowering stages for inflorescences with bracts: An example for this that I see frequently is dogwood. I know enough about botany to know what a bract is and that the actual flowers are the little thingies in between them. However, I assume a lot of the general public will not be as knowledgeable and interpret bracts as petals, thus viewing anything with open bracts as flowering regardless of whether the little flowers between the bracts are open yet or not. This is another case where annotating them as budding would result in not having them included in the project I’m working on, so I’m leaning more towards just going with the view of open bracts = flowering in a broader sense.

  5. Budding/flowering stages for head inflorescences: Similar to the above case of the dogwood, Asteraceae have flower heads with ray and disc flowers, where the disc flowers are often the ones with the reproductive parts and the ray flowers are for attracting pollinators. Should flower heads with expanded rays but still closed disc flowers be “budding” or annotated as “flowering”? Similar to the case of the bracts above, I doubt the general public would even know the distinction.

I think in many of these cases it comes down to the question: Do we go with a more general interpretation of what a “flower” is or do we get scientific about it? Since iNat is geared primarily at getting the general public engaged with nature, I’m leaning towards going with a more layperson’s interpretation for edge cases. Researchers downloading observations for scientific studies should be reviewing for accuracy anyway before using the data (especially since there are no notifications for annotations yet and there is no way to correct wrong annotations made by other people).

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Good questions. The tool tips in the user interface may be helpful:

  • Flower buds: At least one closed flower bud
  • Flowers: At least one open flower

Hope this helps

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  1. If it’s showing buds, it’s showing buds.
  2. I tend to mark it as flowering until you see fruits, as most Araceae have fairly clear fruits. Arisaema is a good example as they produce berries and lose the spathe as they age from flowering into fruiting.
  3. Seems reasonable. If the flower is as open as it’s gonna get, it’s flowering.
  4. and 5. Yeah this is tricky for me. I reckon working with what the general public would notice. I concur that anyone using iNaturalist data for research should be double-checking it anyway.
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The National Phenology Network people have extensive and detailed definitions for phenological stages of different plants, on a species by species basis. One approach would be to use their definitions as a standard, but I think that’s way beyond what we can expect for our users. I guess my point is that it is hard to make simple definitions with wide applicability, so we should just expect these data to be fuzzy in interpreting the phenological curves and maybe not stress too much over precise definitions that can’t be enforced. But the discussion makes some good points.

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