Crocus November 2008

[Michael J Campbell]

A few in bloom yesterday. Feel free to correct names.

Crocus mathewii
Crocus pallasii
Crocus laevigatus fonteyani

[tonyg]

The link that Gerry gave is very informative but also very scary.  I had always been led to believe that the seed embryo was 'clean' but apparently this should not be taken for granted.
The aphids here are found throughout the garden so a hard winter would help reduce the supply of aphids which will always be present no matter how good my plant hygene.  

[Maggi Young]

Michael, such lovely clear photos!

[Luc Gilgemyn]

Great pix Michael !

Here's some from me, having flowered in the past few weeks - I'm fairly new in autumn flowering Crocus and these came as a good start from Tony G. (thanks again Tony !  ) :

Crocus kotschyanus
C. cartwrightianus albus
C. hadriaticus (M5048)

[hadacekf]

Luc,
Lovely pot of Crocus in your photo.

[Lesley Cox]

And the virus spreads very quickly. I had a small group of C. medius, absolutely clean for years. Summer of 06/07 I imported 6 Australian corms which flowered with the same stripes as Howard's and this last autumn all my originals had it too.!

[Gerry Webster]

The link that Gerry gave is very informative but also very scary.  I had always been led to believe that the seed embryo was 'clean' but apparently this should not be taken for granted.

I've always believed this too, on the basis of  the published opinions of  recognised authorities on bulbous plants. However, on reflection, it's not at all clear why anyone should think this. Eggs and pollen grains are, after all, just parts of the plant. Why should they be exempt from viral infection?

[Martin Baxendale]

The link that Gerry gave is very informative but also very scary.  I had always been led to believe that the seed embryo was 'clean' but apparently this should not be taken for granted.

I've always believed this too, on the basis of  the published opinions of  recognised authorities on bulbous plants. However, on reflection, it's not at all clear why anyone should think this. Eggs and pollen grains are, after all, just parts of the plant. Why should they be exempt from viral infection?

I always thought it was to do with speed of growth. That cell growth in seed formation is so fast that there isn't usuallu time for the virus to invade the seed embryo from the parent plant before the seed is fully formed with a protective hardened seed coat that keeps out the virus. So the seed 'leaves the virus behind' in the same sort of way that rapid meristem growth leaves behind the virus in microropagation - the new cells grow so fast that any virus in the original tiny piece of plant material can't spread as fast as the new growth, so gets left behind in the dying old material. I also assumed that the fast cell growth after seed germination could work the same way, leaving any virus behind in the seed. But what I've read recently suggests that if conditions are not ideal for seed formation, eg in unusually low temperatures (say during a cold winter) then seed development may be slowed enough to allow the virus to get into the seed embryo before the seed coat forms to protect it. I would hope that, especially with warmer winters, that means there's still a very good chance of getting clean stock from seeds. With my snowdrop seed raising over the last 10 years or so, I haven't noticed much if any virus in my seedlings, and virus in snowdrops is usually very quick to produce obvious leaf symptoms.

[Gerry Webster]

I always thought it was to do with speed of growth. That cell growth in seed formation is so fast that there isn't usuallu time for the virus to invade the seed embryo from the parent plant before the seed is fully formed with a protective hardened seed coat that keeps out the virus. So the seed 'leaves the virus behind' in the same sort of way that rapid meristem growth leaves behind the virus in microropagation - the new cells grow so fast that any virus in the original tiny piece of plant material can't spread as fast as the new growth, so gets left behind in the dying old material.

Martin - this is what I have always thought too. But is there any evidence for this view? On the face of it, one might think that the replication of a cell (relatively complex)  would be slower than the replication of a virus (relatively simple).

[Armin]

A few in bloom yesterday. Feel free to correct names.

Crocus mathewii
Crocus pallasii
Crocus fonteyani

Hallo Michael,
very nice pictures from autuum species you show us. C. mathewii is a fantastic with its unique color combination .
C. pallasii is a lovely crocus too.
Finally, I also like the last picture of C. laevigatus "Fonteyani"  

[Martin Baxendale]

I always thought it was to do with speed of growth. That cell growth in seed formation is so fast that there isn't usuallu time for the virus to invade the seed embryo from the parent plant before the seed is fully formed 

Martin - this is what I have always thought too. But is there any evidence for this view? On the face of it, one might think that the replication of a cell (relatively complex)  would be slower than the replication of a virus (relatively simple).

I assumed it would be based on straightforward microscopic observation of cell growth in seed formation and virus growth. It's been proven to work with fast meristem growth in micro-propagation, as that's how micro-prop cleans up virussed plants like lilies, producing much healthier, virus-free plants from plants that had a heavy virus load. Of course meristem micro-prop is done in idea conditions, so I can see how temperature variations outside the micro-prop lab could affect the result.

[udo]

some flowers today,

Crocus cartwrightianus, a native white form
   ``    caspius, rose form
   ``    serotinus ssp.serotinus from S-Portugal
   ``    veneris from Cyprus

[Maggi Young]

More pictures from Jim Kee in Delaware..... these of C. laevigatus. These are the white form with the golden yellow markings on the outside with a little form from Crete growing next to them.

[Luc Gilgemyn]

Stunning picture from Jim and Dirk ! 

Dirk,
that pink C. caspius is absolutely delightful !!!

[Armin]

I have to acknowledge the comment from Luc. Absolut stunning

It is remarkable how a species can vary. The white C. laevigatus form with the yellow markings outside and the very branched style compared to the form from crete and the "fonteyani" Michael showed us