Hi,
You have a very good chance of having pure seminole seed. As your neighbor did, most people grow zucchini or yellow summer squash which are C. pepo. It will not cross with C. moschata. So you did not need to pull your summer squash. You also did not need to pull your cukes. Cucumbers are relatives of squash but they are way too different to cross with any squash. The same goes for melons. It is sort of like human, ape, and chimp.
It is possible that a neighbor did grow Butternut which is C. moschata, but the possiblity is lower than zucchini since it is a good sized grower and need a larger garden. The other popular home garden squash is Acorn which is also a C. pepo so there is no chance of crossing with the Seminole.
I hope that all made sense,
Remy

Thanks Remy!!!!!!!!! I've only got 3 Seminole on the vines. I grew them up a cattle panel and started much too late but I will save some of the seed and plant in 2010 - just to see what happens. This is going to really be fun. It is really funny looking at these 3 Seminole. They are all different sizes and kinda like Papa, Mama and baby!

Cheers,
DL

I agree with Remy. Squashes fall into six different species, so you could grow six species all at the same time without concern of cross-pollination. In your case, you have to consider ANY plants within 1/2 mile radius minimum. Must be hard in the city--I live on 20 acres.

The neighbors zucchini is C. pepo so should be safe even if they still had some blooms still on. Other C. pepo squash are acorn, crookneck, scallop, small striped and warted gourds, spaghetti and of course zucchini.

C. moschata squash are butternut, cheese, golden cushaw and many more.

My BEST suggestion is to check out the article at the link below and then if you don't already have a book called, "Seed to Seed" by Suzanne Ashworth --- GET IT! Best investment for seed saving I ever made.

It lists all the different varieties for all kinds of vegetables, along with the info. to determine what you can safely grow side by side without cross-pollination issues. It also tells how to plant, grow, harvest and dry seeds. It is considered our seed saving club's bible.

This year I grew C. maxima, pepo, moschata and mixta species side by side. No cross-pollinatin, no problems. The book is great for planning your garden and seed purchases each year.

Be sure to check out the article I posted about saving pumpkin and other squash seeds. There are several other seed saving articles at my site there; onions, sweet potato slips, seed life guide, seed storage, etc.
Link is below.

Here is a link that might be useful: How to Save Pumpkin Seeds, Squash & Gourds