Tips on Harvesting and Photographing Seeds

When most people photograph plants, they may think of flowers (or cyathia in the case of Euphorbia), bracts, and leaves. These characters are essential for identification, but in Euphorbia there is another part of the plant that is usually not photographed or even thought of in the field. These are the seeds. Seeds are often essential to a fast and reliable Euphorbia identification, but not often photographed since they are difficult to obtain in the field. However, most taxonomic keys concerning Euphorbia need seed characteristics to work. And while it is possible to identify most species without seeds, for some, it is not.

A word of caution, there are protected species in many parts of the US (especially California, Arizona, and Florida) and it is illegal to gather seeds from National Parks. In most situations, though, you'll be safe gathering seeds. Now on to the fun stuff.

Collecting and photographing seeds may be easier than you would think depending on what kind of camera you have. It just takes a few extra steps. And as you read this, remember, any additional information is better than no information at all, so don't be embarrassed by your results. Let them inspire you to experiment until you've reached the limitations of your camera.

Collecting Seeds

Preparation if you have permission to take material

Take one or more branches with fruits and put it/them in a piece of paper (a paper envelope works well too). The more branches you get, the more seeds you will end up with. Fold the piece of paper in half so that the branch/branches is/are in the crease. Then, fold the edges of the paper upward so that the seeds don't escape. You could also take a plant specimen if you know how. As the plant dries, you may hear popping. The fruits explode to disperse the seeds. The drying should take less than a week depending on the climate you live in. If none of the fruits opened, you may not have gotten fruits that aren't quite old enough, but you still might be able to get good seeds. Also, there are a few species that may hold on to their seeds a bit tighter than others, so prying them open might be useful.

You can open a fruit by separating it into the three carpels, taking one or all of the carpels, and flick off the beak-like projections at the tip (where the styles where). This will release the seeds. Some tweezers and a dissection needle may be useful, but if you have a steady hand, this can be accomplished with a fingernail.

Preparation if you don't have permission to take material

With practice, this can be done in the field too but requires the ability to recognize what fruits are mature enough to produce seeds that don't have a yellowish, light tan, or translucent seed coat (all indicators that the seed isn't mature). These fruits usually stand straight up or are just starting to curve upward. They will be close to the largest fruits but a little smaller since the start shrinking due to moisture loss just before dehiscence. The curving is from the recurved pedicels that the fruits stand on, but they usually straighten as the mature fruits start to dry. Not all species have the recurved pedicels, but most of the North American species do.

To separate the carpels, rub the fruit between your fingers. This is sometimes enough to release the seeds. If not, pry or flick off the beak-like projection at the carpel tip with your fingernails or dissecting tools. This process may be facilitated by putting the fruits in a ziplock bag before opening where the seeds will not go flying once they are released.


What to photograph:
With seeds, it's good to get several angles to understand the overall morphology. The easiest way to do this is to have a bunch of seeds and spread them out on a flat surface like in the following photos (the second is with a cell phone).

If this isn't possible or if you only have one seed, you will have to be more careful. In almost every Euphorbia seed, there are four faces. Two of these are longer than the other two. It is generally best to photograph from an angle that displays both a long face and a short face.

This isn't always the case or always necessary, but it helps a lot in the vast majority of cases. For more specific info, you might find my Advanced Seed Morphology post helpful in conjunction with a good description of the species you are interested in.

Not all cameras are created equal. The ideal method is to shoot on manual mode with manual focus (as opposed to autofocus) and use a flash. This is not always possible. If you find that you can use manual mode but not manual focus or vice versa, use the manual in combination with the auto instead of using all auto.

Full Manual Mode:
Switch your camera to manual mode and open or turn on your flash. Set the shutter speed to higher than 1/150 of a second (if you can stay very still, you might be able to get away with less). I use 1/200 or 1/250. Change your aperture (F-stop) to a high number. I use F9, but this depends greatly on your lens. Turn your ISO setting as low as you can (typically 100 or 200). Turn your autofocus off.

Dealing with Automatic Settings:
This should not cause that much of a problem if you use a flash. If you are unable to a flash, use bright sunlight or a bright lightbulb. The only problem is that it will typically keep the F-stop lower than you would normally want it.

Dealing with Autofocus:
This is the hardest to deal with. You may have to play around with it. Typically, you can discover the limitations of the lens by putting your hand as far away from your camera as you can (while still being able to see what you are taking a picture of) focus on your hand and bringing it closer to your camera until the camera can't focus. This will also work on a wall, tree, or really any relatively flat object (though, you will have to be the one moving instead of the object). The distance where you can just barely focus is the ideal focusing distance for photographing seeds (and other small things).
For some cameras, you may have to zoom in. For some cameras, zooming in only makes it to where you can't get as close and makes a worse picture. It all depends on your camera.

Dealing without a Flash:
This is not much of a problem. Use bright sunlight or a good light source like a flashlight or bright lamp. These light sources will sometimes cause shadows that can complicate identification, so it's good to have several seeds in the shot so that the seeds are viewed from several angles. That way, a better understanding of the seed morphology can be determined.

Dealing with the Camera in your Phone:
I have limited experience here but I do know that relatively good photographs can be obtained with an iPhone (last photo from this observation: The iPhone (and potentially other phones) have the ability to focus before firing. If yours can do this, use the information in "Dealing with Autofocus" and "Dealing without a Flash." I would highly encourage discussion and experimentation between people with different types of phones.

Taking the Picture:
Put the seeds on a light colored surface (or you can keep it on the white paper). Brace your arms, body, and/or hands in whatever way works best for you (if you have a tripod, this is better, but can take a minute to set up). Focus as closely as you can, move your camera back and forth until you think the seeds are in focus, and take the shot. This last part can take a little patients and practice.

The same techniques can be applied to other structures like stipules, cyathia, or hairs (or even macrophotography in general). Though, these characters are typically visible in a normal photograph, so less planning is needed to photograph them. You can also apply this to other types of small plant structures if you are interested.

Seeds and Fruits project

הועלה ב-פברואר 2, 2017 08:39 אחה"צ על ידי nathantaylor nathantaylor


Excellent guide, thank you!

פורסם על-ידי nanofishology לפני כמעט 6 שנים

Thanks for this, Nathan. I have a proper macro lens (Sigma, 105mm), but can use some specialist help in using it better.

פורסם על-ידי mavourneen לפני יותר מ 3 שנים

@mavourneen If you'd like, you can send me a message and we can discuss this further.

פורסם על-ידי nathantaylor לפני יותר מ 3 שנים

Again, thanks Nathan. If I have hassles, I'll be sure to post you for advice.

פורסם על-ידי mavourneen לפני יותר מ 3 שנים

Thanks for this excellent information, Nathan!

פורסם על-ידי annikaml לפני בערך 3 שנים

Great information! A low cost option I went with in Obs. #138036154 was to use a USB microscope which are, at time of this comment, less than $50 USD at the usual online retailers. It may be an option for folks who don't want to spend a whole lot for a nice macro camera.

פורסם על-ידי vreinkymov לפני 11 חודשים

הוספת תגובה

כניסה או הרשמה להוספת הערות