"Pokok letup-letup" or "pop plant" of "puff plant" or "puffy plant", used to be a common weed in Malaysia. However, in the past years, the ubiquity of the plant, whether it is in the open areas,wastelands or rice fields have since dwindled. The scarcity of the plant these days has made me to think that the plant has become close to extinction. What a joy when I saw the plant a few days back. It reminds me of my childhood days.
The plant is small with height of about 30 cm. The main stem branches into two directions at about 10 cm from the ground. Each branch will again divides into two smaller branches. In this way the plant keeps itself close to the ground, thus avoiding breakage of its angular and hollow stem during windy days.
Information obtained from the Internet revealed that the name "pokok letup-letup" has been assigned to two different and taxonomically unrelated species of plants. The one that I describe here has the scientific name of Physalis minima L., which belongs to the family Solanaceae (same family as tomato). This assignment is agreed upon by some writers. Some others, on the contrary, assign this common name to the species Passiflora foetida, the creeping wild passion plant. Those who are in favour of Physalis minima assign the other common names such as ulat bulu (hairy caterpillars plant) and letup-letup kelambu (mosquito net pop bush plant)to Passiflora foetida.
Common sense tells us that the name "letup-letup" may have arisen from the nature of the fruits when they are young. As can be seen from my earlier post on P. foetida the fruit of the plant is covered with a network of tendril-like structure (which is the reason for the name mosquito net). When the fruits are young, the seeds inside them are small, and the fleshy and jelly-like testa covering is not yet formed. Hence the fruits have a lot of empty spaces. The air occupying the space will give a pop or puff sound when the fruits are rapidly squeezed in between the thumb and the second finger.
On the contrary, in P. minima the membranous covering around the fruit (which looks like small tomatoes) is air tight. When it is squeezed it will also give a pop or puff sound. Due the sound that they make, children in the rural areas like to play with these fruits. For those who have never seen this plant may have called the P. foetida as the "pokok letup-letup", but for those who have seen both the plants, and seen them at the same place and time, have no doubt that P. minima is the real "pokok letup-letup".
The plant is widely distributed in the tropics. There are reports of its existence in South-east Asia, South India, Northern Australia and the Pacific Islands.