Tomato (seedling)Lycopersicon esculentum “Fleischtomate, kartoffelblättrige, Tiefgefurchte” german heirloom
Sometimes a tomato variety is labeled “potato-leaved”. A first it sounds a bit weird, but as soom as you see the leaves you get used to the expression. Tomato and potato are relatives belonging to the nightshades, and share the disease late blight. Keep them well apart in the garden, as the potatoes are likely to infect the tomatoes (as far as I know not the opposite direction).
One might think potato-leaved tomato is a result of genetic engineering, but in fact its a pure tomato of a rather primitive type as seen in the flowers. The stigma protrudes from the anther “barrel”, seriosly increasing the risk of having a cross with another tomato variety. Look out for signs of a cross in new generations. If I find signs of a cross, I look into my seedbox and find seeds two or more generations older. These old seeds are before the cross happened, and this is a reason to keep your old seeds for many years. Tomato seeds are very longlasting in the seedbox. On the other hand, taking seeds from plants showing signs of crossing is a new variety in making.
Seedlings with normal leafs to compare:
Red beef tomato (seedling)Lycopersicon esculentum ‘Virovskij Skorospelij’
Black cherry tomato (seedling)Lycopersicon esculentum ‘Black Cherry’
In the toad's garden 
April 2, 2008 at 13:57
The other thing about potato leaved tomatoes is apparently they have more open flowers and can cross more easily. Have you heard this too? I recently purchased some tomato seeds from the Seed Savers Exchange website, and printed on the back of the packets is the following:
“Seed Saving Instructions: Cross-pollination between modern tomato varieties seldom occurs, except in potato leaf varieties which should be separated by the length of the garden…”
April 2, 2008 at 20:52
Mainstream tomato flower have a shorter style, so short in fact, that it ends inside the anther barrel. As the pollen sheds from the anthers it drops directly to the stigma at the end of the style, inside the barrel. I guess it can be quite dusty in there. Potato-leaved tomatos with the longer style holds the stigma out of the barrel, out where pollinating insects rule, in the world of cross breeding. Since the tomato flower usually points downwards, it’s still very likely to selfpollinate, but insects are not excluded. A risk or a chance?
April 24, 2008 at 13:24
I’m growing a couple of potato-leaf varieties at the moment and I didn’t know they had a protruding stigma. Thanks! I shall be careful where I plant mine … and maybe put a bag over one flower truss to keep it pure for seed saving.
But as you say, whether it’s a “risk” or a “chance” is a matter of perspective!
April 24, 2008 at 20:22
Rebsie: Look at the flowers, to decide if you need to bag them or not. I guess there could be some potato-leaved tomatoes where the stigma doesn’t protrude. These small significant details are interesting to notice.
May 10, 2008 at 20:29
[…] Potato-leaved tomato I […]
April 20, 2011 at 18:32
I was just looking at this subject, might do a blog post on it as well. I have some Japanese black trifele tomatoes coming up. They are potato leaved as well.