Plants with more than one type of seed

[Lis Allison]

I've been challenged to ask here about plants with more than one type of seed. The question came up on Alpine-l, relative to Castillja seeds, and someone posted that the genus Dimorphotheca was called that because of its two different types of fruit. So I did a Google search on Dimorphotheca, but while there were many many references to its multiple fruits, I couldn't find either a description or an image of the plant or its fruits.

Anybody have a reference? Or images? Or knowledge? Why would a plant have different fruits? How the heck did that evolve? The idea of plants with more than one type of seed intrigues me.  Don't know why, just does!

[McDonough]

Hello Lis,

I've been following the Alpine-L discussion on this curious Castilleja seed question.  Probably the best solution is to make an experiment out of it, sow two pots, one with the small black seed and one with the larger seed having the noticeable "seed coat", then see what germinates.  I realize it is Jane Hendrix that posed the question in the first place, and I can point her over to this discussion here.

I wonder if its a simple case of viable seed versus non-viable seed, again an experiment might reveal some answers. In my seed cleaning activities, I have sometimes spotted seed that seems underdeveloped, some rudimentary runt seed that I figure is not viable, but will not waste much time trying to separate it from the good seed.  Then there are dramatic cases like Paeonia, many species that have pods that split open to reveal showy red-orange "seeds", but in fact the firm red-orange ones are not viable (as pretty as they may be), the fertile seeds are plump dark-black "berries".  With blissful ignorance two years in a row I sowed bright red seed collected on my P. wittmanniana plant but had zero germination, then this year saw a fertile seed and it all clicked and I realized my mistake... so I admit to being a total newbie when it comes to Paeonia.  This example illustrates the strong differences in viable/non-viable seed.

[Middleton]

Hi Lis,

In 2008 I came across two types of seed when cleaning a purchased Dimorphotheca.  One type looked calendula shaped but the majority were in a papery sheath.  The discussion on Alpine-L got me looking through my seed box. Found several old 'calendula cones' and lots of the other type.  I did sow the calendula shaped in 2009 but put the pot outside in February and only one germinated. I should have sown them 'warm'!
What I actually what to pass on is an illustration page found using Google.  I remembered Googling in 2008 this unusual 'one flower, two seeds type' phenomena. 
There is one flower species that produces three types of seed!  Amazing!

http://www.frsa.org/Seedimages/janesmultforms.html

Would have posted on Alpine-L but waiting for a password reminder 

Sharon Middleton, Zone 5, Georgian Bay, ON

[RickR]

This has got me thinking about species that normally grow both sexually produced seed and asexually produced seed.  Genera like Leibnitzia or Viola.  Has anyone noticed a difference in these seeds?

[Lis Allison]

This has got me thinking about species that normally grow both sexually produced seed and asexually produced seed.  Genera like Leibnitzia or Viola.  Has anyone noticed a difference in these seeds?

Not in native Eastern Ontario violets. I've looked at both types of seeds of all of them that make them both ways, and they all look the same.

[McDonough]

What I actually what to pass on is an illustration page found using Google.  I remembered Googling in 2008 this unusual 'one flower, two seeds type' phenomena. 
There is one flower species that produces three types of seed!  Amazing!

http://www.frsa.org/Seedimages/janesmultforms.html

Sharon Middleton, Zone 5, Georgian Bay, ON

Very interesting link Sharon, seems that Dimorphotheca and the other examples are all Asteraceae (with Dimorphotheca in the Calenduleae "tribe" of Asteraceae), perhaps composite flowers which have two types of florets in their flowers has more capacity for creating two types of seed, but that is purely conjecture.

Found a link showing photographs of Castilleja exserta seed pods and seed, but wish there were some higher resolution links to see the photos larger.
http://www.delange.org/OwlClover/OwlClover.htm

This site is interesting, 5 shots of Castilleja (photos annotated with flower parts), Castilleja5.jpg shows a microscope view of seed... they look like faceted honeycombs!
http://www.inhs.illinois.edu/~kenr/prairiephotos/

Castilleja integra with seed
http://4.bp.blogspot.com/_jM_mofC7B18/TI_N560_GNI/AAAAAAAAEJ4/mcK7K0mNRdI/s1600/Castilleja.jpg

C. coccinea - close-up of seed
http://www.prairiemoon.com/images/D/Castilleja_coccinea_Indian_Paintbrush_seed.jpg
http://www.prairiemoon.com/seeds/wildflowers-forbs/castilleja-coccinea-indian-paintbrush/

C. sessiliflora - close-up of seed
http://www.prairiemoon.com/images/D/Castilleja_sessiliflora_Downy_Painted_Cup_seed.jpg
http://www.prairiemoon.com/seeds/wildflowers-forbs/castilleja-sessiliflora-downy-painted-cup/?cat=249

Castilleja flava seed - microscope view:
http://www.nature.com/nature/journal/v443/n7107/images/443031a-i1.0.jpg

Note:  the Prairie Moon Nursery links above are typical for this excellent site, not only do they have extensive listing of native plant species (seeds), but in most cases they show close-up of the seeds as well, checkout out their Carex seed offerings and other seed:
http://www.prairiemoon.com/seeds/?sort_direction=1&page=3

This photo might be the secret link, it shows a microscopic view of the seed, and what I see is a sort of honeycomb exoskeleton outer layer and a smooth almond-like kernal inside... maybe the seed coating (the crumbling exoskeleton) is easily rubbed off or sometimes crumbles away on it's own, leaving behind two apparently different seed types, but in fact it's actually one seed type but the exoskeleton is "expendable".  This is simply conjecture once again based on my interpretation on what I see in the crisp photographs:
http://drystonegarden.com/wp-content/uploads/2009/12/banking-on-life-kew-exhib-007.jpg
http://drystonegarden.com/index.php/tag/seed-bank/

I hope this helps... a fascinating subject. 

PS: I might be moving this topic to the "Propagation" board, when I do, I'll leave behind a redirecting link.

[IMYoung]

On the subject of castilleja seed, Mark wrote elsewhere:" In one of the close-up photos from Prairie Moon nursery, one can actually see a seed "kernal" inside what appears to be a regular seed, that kernal matching a few other of the smaller, simpler seeds among the many... seeds with their outer "exoskeleton" crumbled off.
Does anyone know the actual botanical term for such a structured "seed coat"?  What purpose does that honeycomb-like seed exoskeleton serve...
is it for capturing an supplying moisture to the seed, or oxygen to the
seed; my guess would be for preserving moisture."

I am inclined to think that the "exoskeleton" will serve both to preserve moisture round the seed AND to allow oxygen to be kept around it.....and that these are both important features : for sure moisture and air are essentials for plants at their roots so I imagine these are equally important factors for a seed, too and this elegant structure is a really neat way to achieve this.
Everything about seeds is fascinating though, isn't it? All that life contained inthose tiny packages, just waiting to get the right signals to start growing - magic!

[Weiser]

The seed coat allows the seed to have more surface area thus increasing it's bouncy in moving air. When I collect Castilleja seed I have to be careful of slightest breeze  blowing the seed away, before I can empty the capsules. It dose little good to winnow the seed as it is so light that you reach the point of diminishing return for your efforts quickly.

Interestingly I have noticed that Penstemon seed have a similar type of light outer husk/coating around their seed. It also catches air movement and can be rubbed away to reveal the seed kernel which is always much smaller than would be expected by the over all size of the seed.

[Hoy]

I wonder if its a simple case of viable seed versus non-viable seed, again an experiment might reveal some answers. In my seed cleaning activities, I have sometimes spotted seed that seems underdeveloped, some rudimentary runt seed that I figure is not viable, but will not waste much time trying to separate it from the good seed.  Then there are dramatic cases like Paeonia, many species that have pods that split open to reveal showy red-orange "seeds", but in fact the firm red-orange ones are not viable (as pretty as they may be), the fertile seeds are plump dark-black "berries".  With blissful ignorance two years in a row I sowed bright red seed collected on my P. wittmanniana plant but had zero germination, then this year saw a fertile seed and it all clicked and I realized my mistake... so I admit to being a total newbie when it comes to Paeonia.  This example illustrates the strong differences in viable/non-viable seed.

Mark, the red peony seeds are bird attractors! They are supposed to eat the red ones and the black ones too and disperse the black ones in their droppings.