Sarracenia alata – the Pitcher Plants2 Maret 2010 pukul 03:52 | Ditulis dalam Uncategorized | Tinggalkan komentar
The North American pitcher plants (Sarracenia) are divided into two groups: the northern pitcher plant (Sarracenia purpurea), in the northern United States and adjacent Canada, and the southeastern pitcher plants. Sarracenia alata is one of the southeastern pitcher plants, and can be found from eastern Texas to Mississippi. Here’s a picture of it near Mobile, Alabama. At first glance, one only sees the pines, and pine forests in areas of white sand that stay wet in the summertime are habitats for most of the southeastern pitcher plants.
If you’re looking for Sarracenia alata, you want to look for areas of pine forest. Not dense pine forest, but pine forest with meadow-like openings in it. These areas are waterlogged even in summertime because there are dense soils (clays, for example) underneath the white sand, so that water forms shallow pools or isn’t far beneath the surface. These areas are acid–pines are good indicators of acid). And these boggy areas are poor in nutrients, notably nitrogen. The pitcher plants can get enough nitrogen from digesting insects to make up for the lack of nitrogen in the soil. Each tubular pitcher (leaf) contains a small pool of water, which contains insect-digesting chemicals (enzymes) at the bottom of the tube.
Here we see a flower and three leaves of Sarracenia alata. The leaf at left hasn’t opened yet. The leaf in the middle is seen from the front. Notice the light green zone like a V at the mouth of the pitcher–that’s where an insect lands and begins its exploration of the pitcher. It’s looking for nectar droplets on the inside of the hood of the pitcher. Extending down from the V is a dark narrow fold that represents the margins of the leaf–as though they were sewn together like the seam in a cushion. The word “alata” in Latin means “winged,” and this narrow wing on the front of the pitcher gives the plant its name. The leaf at the right is seen from the side, and we can see that the tip of the leaf forms a hood that overarches the mouth of the pitcher. The hood helps guide the insect to climb down into the tube, and it may also prevent rainwater from diluting the digestive fluid in the pitcher.