Loog Tum Leoug ลูกตำลึง
Ivy Gourd, also known as scarlet-fruited gourd, grows wild throughout Thailand. After the rains, it often grows and sends out long shoots along fences. The young leaves and shoots are popular in soups and stir fries. In Thailand, people eat the fruit, but not as frequently as the leaves, so while you see the leaves at markets, you rarely see the fruits. This differs from the US, where you can find the fruit at Indian markets under the name Tindora, but never the leaves.
While the plant belongs to the cucumber family, the flavor is richer. The fruit is green with whitish stripes going from end to end, similar to a watermelon. In fact, it looks like a miniature watermelon. It's about 2 inches in length and ½ inch in diameter. The fruit ripens from the inside out. I took this picture on the right before I picked the gourds. They were mostly green. Just overnight, 2 of them turned bright red. The ripe fruit is soft and sweet while the green fruit is bitter. There are actually 2 varieties: bitter and non-bitter. The variety common in Thailand is the bitter one. The variety we've found at the Indian markets in the US are not bitter.
I first saw Ivy Gourd growing wild in Hawaii. After some research, a USDA webpage shows it also grows in Texas and Florida. The plant is a climber and regarded as weed. In Thailand, we control this type of weed by eating them! To prepare the gourd for cooking, it's cut cross sectional and wash with salt and water to remove the bitterness. The most common way of cooking is to add it to curries.
Like cucumbers, they're also good pickled. Warning: do not prank innocent people with bitter pickles.