Thank you so much! I thought it looked like a lily type but I kept counting 5 petals in my photo and didn't climb back up on the bank to look to see if it really had 6! Thanks for the help. :) Lynda

Aurinia saxatilis, Basket of Gold. Here is a link that might be useful: Google image results

It might be cassia herbecarpa or wild senna, a native plant. Here is a link that might be useful: wild senna

It's Turnera ulmifolia aka Yellow Alder, a tropical species that has naturalized in parts of Florida and Hawaii. Please note it is considered invasive in some areas. Here is a link that might be useful: Yellow Alder