Name that mystery vine
In early springtime, a vine with large leaves started growing in a mound of dirt in my yard. Soon bright yellow flowers bloomed, and after a week or two, something small and mostly green started to sprout.
I thought perhaps I had dropped pumpkin seeds or watermelon seeds on the way to the compost pile in the backyard. The mystery plant seemed like a gourd or melon, as it got larger, with a thick stem connected to the vine.
I sent a photo to firstname.lastname@example.org (which is answered by members of the Travis County Master Gardener Association) for help with identification. The response said the plant had leaves similar to a Tatume squash, "but the fruit itself is a bit different."
A what? I’d never heard of this, so perhaps it came to my yard via bird droppings or some other way. Hmm.
An article on www.texasgardener.com says Tatume has rapid vine growth, and "it is not uncommon for it to send out 12-foot vines in all directions."
Also, it says, the fruit of the Tatume "is round or oblate in shape. The skin of the fruit is striped green and resembles a small watermelon or pumpkin in immature form. The fruits develop quickly. … If it is receiving ample water, it will go from the size of the end of your finger to harvest size in about a week." The article recommends picking it when it reaches the size of a baseball. (Too late, in my case. This was already about 6 inches long.) Any bigger, it said, and "the seeds begin to get firm and make the flesh a lot less fun to eat." Though I’m unclear about what makes this no longer "fun" to eat, it was time to cut it open to explore.
My husband and I cut it off the vine. After slicing it open, we found the insides were pale yellow with plenty of seeds. It looked like a squash to us.
I sent a new photo to the Travis County Master Gardener Association email, and a thorough and helpful response said: "Most summer squashes are grouped within the Cucurbita genus and pepo species. Tatume … is a specific cultivar of Cucurbita pepo that resembles the volunteer plant in your photos."
According to Texas A&M AgriLife Extension website, the Tatume, "also often called Calabacita" is a "hardy, open pollinated native of Mexico" that grows well in hot climates.
So, it seems the mystery is solved.