Spinach Plants and Broccoli Plants
Why would either of these plants grow with a center stalk growing taller than leaves with yellow flowers. Both plants have different styles of flowers but both are yellow. I took some pictures but didn't know how to post them.
Your broccoli and spinach are "bolting". These articles explain bolting: https://www.gardeningknowhow.com/edible/vegetables/vgen/what-is-bolting-what-it-means-when-a-plant-bolts.htm