Posted pollen diameters

I have posted a spreadsheet that is arranged by my expereimental highest to lowest pollen diameters.


It will be updated as I find time to measure more of my samples.

If you would like to have a pollen diameter determined, I will attempt to do it with the understanding that I can then post the results in this spreadsheet and that I can use any of the excess pollen in my own hybridization. (Of course, I can only determine a limited number of “outside pollen” so please keep your requests to a finite number.)


I found it easier to update the spreadsheet by giving it a new link:

David Zlesak’s has also determined pollen diameters ( ). Both of us used the same stain so I would of expected close agreement. Unfortunately, this does not appear to be the case. For example:

My Carefree Beauty is 37.0, (standard deviation 2.7) and Dave’s is 41.3 (SD 1.6).

My Rainbow Knockout is 36.8 (SD 3.3) and Dave’s is 39.6 (SD 3.3).

My Golden Wings is 34.0, (SD 3.7) and Dave’s is 40.9 (SD 4.6).

My Suzanne is 33.3, (SD 2.1), and Dave’s is 38.8, (SD 2.9).

My William Baffin is 37.8, (SD 3.3), and Dave’s is 41.0, (SD 3.6).

My John Davis is 36.9, (SD 1.5), and Dave’s is 39.5, (SD 2.0).

I generally used 4 measurements per pollen grain and normally at least 10 grains per study. Some of my microscope pictures are at:

I posted a question about how to measure the diameter at a microscope web site:

So far only one person has replied, I do not know if the other people who viewed the post did not reply because they agreed with the one reply or did not know.


I tried plotting Dave’s numbers versus mine and the discrepency is not a simple offset. Dave, in the article cited above mentions that pollen diameters may depend on: “pollen maturity, location in the inflorescence, time of pollen grain development during flowering season, temperature, nutrition, and moisture conditions.” Thus, it is probably worthwhile for me to remeasure roses that I measured earlier. There is not much in bloom now, but I was able to harvest some John Davis and William Baffin pollen today. After drying for a day or so I will measure them and compare with my earlier measurements.

Hi Henry! Thank you for all you are doing to make these measurements and sharing data with us. THank you especially to for your help with webcams for better microscope pictures. There seems to be a lot of things that seem to affect pollen diameter like I found referenced by others. One thing that I have been trying to do has been to measure 30 to get a lot to average and to try to be really choosy to measure only those that are very round and really well stained to avoid those that may have aborted later in development and may not be viable. Maybe you are already doing the latter and the differences are for other reasons. Did you purchase stain? Maybe our stain recipes are a bit different perhaps? I boiled carmine in acetic acid under the fume hood for 45 minutes until I had a saturated soluation and then strained it. I got that recipe from an old stain book. Perhaps the acetocarmine stain sold is a bit different because maybe they didn’t boil it as long? What do you think Henry?



I found this recipe for acetocarmine when you recommended it to me David:


Today the John Davis pollen was “ripe”. I measured 13 pollen grains (52 measurements) and obtained an average of 32.9 and a Stardard Deviation of 2.8.

My initial data for John Davis was 36.9, SD of 1.5, and Dave reported 39.5, SD of 2.0.

John Davis is a triploid so it is not the best choice for a comparison. However there is not much in bloom now. The TV weatherman said so far this has been the second coldest July on record in the Cleveland, Ohio area.

Hopefully, tomorrow some of the William Baffin pollen will be ready.

For William Baffin I measured 18 pollen grains, each 4 times to give a total of 72 measurements. I obtained an average of 37.1 microns (micrometers) with a Standard Deviation of 3.8.

My earlier measurenent gave 37.8 with a SD of 3.3, and Dave reported 41.0 with a SD of 3.6.

Might I suggest that Henry and David (not the fruit sellers but the rose growers) are perhaps measuring a different selection of pollen grains. David notes that he looks only at fully round, well-stained grains. But Henry always does 3 measures per grain because they are rarely round in his experience. So it is likely that he is looking at ovoid grains where the average “diameter” will necessarily be less than the maximum. This may lead to the consistently smaller average that he gets. Perhaps we need a slide exchange to resolve this. The quality of the pollen produced by a plant will affect how different these two procedures are in getting averages, even if the staining is identical and the measuring tools are exactly calibrated.

I took 4 measurements per grain. The 18 William Baffin grains in the last set can be viewed at:

To go to the next grain, click the right arrow above the picture.


Using Henry’s method of four measurements each of 18 grains of William Baffin pollen, my average pollen diameter is 40.6.

Here’s a link to photobucket showing a slide of William Baffin pollen measurements made yesterday. I used methylene blue as my stain.

Ooops. Here’s the link.

Thank you margit but the link still does not work on my computer. I am not familar with photobucket. If it is similar to picasa, there may be a procedure that you have to go through to allow all others to view the picture. Could you also give us your standard deviation?

Larry my selection procedure is to eliminate grains that do not stain and the very, very few that are much, much bigger than the others.

For triploids it would be nice to have a program that automatically places the 4 individual grain measurements into the diploid and tetraploid subgroups of data. In my younger years I probably could of written one as fast as I am typing this, but now…

You’ll have to copy the link and paste it into your browser–or try the link below.


The link below takes one to the first of 12 John Davis pollen slides (13 measurements).

This set is of interest because John Davis is triploid so both diploid (smaller size) and tetraploid (larger size) pollen are expected to be present.

To go to the next slide, click the right arrow above the picture.


I probably should comment on the big diference between the quality of the William Baffin slides and the John Davis slides.

John Davis released its pollen normally, I had to crush the William Baffin anthers to get any pollen.


Do some triploids produce a mix of X1 as well as X2 pollens?

George, theoretically yes. AND in Dave’s recent paper ( ), he confirmed this experimentaly. To quote: “In crosses between tetraploid female and triploid male parents both tetraploid (n=20) and triploid (n=23) offspring were found in an approximately equal proportion (Table 9).”

Henry, I calculated the SD for my William Baffin using the Excel Spreadsheet tool. It was 5.93. For whatever it is worth, my William Baffin produced a LOT of pollen.

Today I redetermined the pollen diameter of Carefree Beauty. I did 4 measurements each on 10 pollen grains. I obtained an average of 41.5 microns and a standard deviation of 2.1.

In my earlier determination again utilizing 4 measurements each on 10 pollen grains, I obtained 37.0 microns and a standard deviation of 2.7.

David Zlesak in his published paper in (Floriculture and Ornamental Biotechnology, 2009( )

reported 41.3 microns and a standard deviation of 1.6.