Background
Pitcher plants are scattered around the world. Apart from Nepenthes and Darlingtonia, there are two more pitchers with different genus that are generally known as the American pitcher plants. Namely, Sarracenia and Heliamphora that both under the family of Sarraceniaceae. They are referred to as passive carnivores in which they use a passive preying mechanism that solely relies on the nectar and color or pigmentation of the modified leaves without any structural movements of the leaves at the cellular level. Sarracenia is one of the simplest perennial carnivorous plants to cultivate that is commonly known as purple pitcher plants. The natural and typical habitat is the southeastern coastal plain of North America. They are mostly found in the area that is permanently wet, open, grassy savannas, fens, swamps, as well as similar wetlands. Heliamphora is commonly known as sun pitcher, as Heliamphora from Greek means sun. This genus consists of twenty-three species that all Heliamphora taxa are narrow or extremely narrow endemics. It is native to the Guayana Highlands of southern Venezuela, Guayana, and northern Brazil.
Morphology
Both Sarracenia and Heliamphora have a showy, brilliant, elegant, and very unusual floral structure that acts as the bonus of these unique tube-like pitcher plants. The flowers are scented and in bloom for one to two weeks. The tubular pitchers of Sarracenia and Heliamphora are pretty simple. Both give an inverted cone shape of tube-like modified leaves.
Heliamphora has funnel-shaped leaves. The pitchers are relatively stiff as compared to other carnivorous plants. However, the stiff texture of the pitcher made it very brittle and easily damaged. Morphologically, Heliamphora has a smaller leaf front as compared to that of Sarracenia and the absence of white color spots as pigmentation in Heliamphora. The flower stalk of Heliamphora inflorescence may be up to twenty-four inches tall each with delicate white petals that change to pink color gradually with age.
Interestingly, both Sarracenia and Heliamphora have grown in such a way that the mouth of the tubular pitchers is facing to each other of the same plant or become inwardly rather than facing outward like that of Darlingtonia.
Preying mechanisms
Sarracenia attracts insects with bright color or pigmentation of their pitchers. The colors vary from species to species which are red, purple, green, or yellow. It is an open tubular pitcher that collects rainwater to drown the insects and slowly obtain the nutrients from the bodies through bacterial decomposition and breakdown by weak enzymes. The luring mechanism is similar to other carnivorous plants in which the nectar is called a nectar spoon, which is found all over the pitcher’s mouth to seduce insects. The attractive nectar contains a drug, presumably coniine that assists the preying mechanism by its paralysis properties that bring intoxication and eventually caused the death of those insects.
Generally, Sarracenia catches the prey in a pitfall method. The wing-like projection, also known as the front seam of the leaf, plays a vital role in the preying mechanism. The underneath surface of the front seam is found slippery. Therefore, insects underneath the leaf that are resting and avoiding sunlight will eventually slip and fall into the tubular pitcher containing “juice.” The insects cannot escape easily even it is an open system. This is because the inner wall is waxy and there are downward-pointing hairs that prevented the insects from climbing up, thus drowning the prey in the tubular pitcher. Sarracenia psittacine is a tubular carnivorous plant that often mistaken as a species of Darlingtonia due to its morphological structures that looks like cobra lily without the “fangs.”
However, Heliamphora is considered the most primitive among those of the pitfall carnivores. Apart from the nectar, the color, and pigmentation of the pitcher that gives red, gold, and green. Occasionally, the insects fall into the trap with the prey slips and fall into the gaping pitcher. A plus mechanism has downward-pointing hairs that are found on the lining of the interior pitcher that make them intricate escape. This cone-shaped pitcher has the smallest leaf front as compared to other pitchers. As compared to Nepenthes and Sarracenia, this sun pitcher does not have a big leaf, font seam that acts as a resting platform for insects. Each funnel-shaped pitcher has a tiny overhanging cap which less likely involved in the preying mechanism.
Propagation and care tips
Production of seeds of Sarracenia requires bees as pollinators or artificial cross-pollination. After successful cross-pollination, the seedpods will slowly tilt upward so that the seeds will not become trapped in the upside-down umbrella-shaped style of the seedpod, thus allowing seeds dispersal. Propagation of Sarracenia can be done by splitting through division or the formation of new plantlets from rhizomes. The most popular horticultural practice of Sarracenia and Heliamphora are using sphagnum moss as the substrates that stay in wet conditions in a greenhouse or grow them in peat bogs or the sodden ground at the edges of the pools that exposed to the sunniest areas. Some hobbyists grow different species of Sarracenia in a used bathtub or large containers to make a mini scenery that is full of colorful “tubes” and to ease the process of cross-pollination to produce hybrids.
As opposed to others of the same family and other types of carnivorous plants, Heliamphora is considered as one of the most difficult carnivorous plants to cultivate by plant enthusiasts and experts. For highland species, a cool condition is needed. Whereas, lowland species prefers warm temperature. However, both favor high humidity conditions. The substrate, sphagnum moss, for example, has to be moist but not sopping. Crown divisions and leaf pulling are found useful in propagating Heliamphora vegetatively. The formation of plantlets from the rhizome will also be observed. Germination of seeds is an alternative to propagation but low success rate due to the different immature periods of the pollens on the anther and stigma. Seed germination also takes several weeks or months to germinate.
Further Readings:
Meyers-Rice, B. (2006). Growing carnivorous plants. Timber Press.
D’amato, P. (2013). The savage garden, revised: Cultivating carnivorous plants. Ten Speed Press.
Ellison A. M. & Adamec L. (2018). Carnivorous Plants: Physiology, Ecology, and Evolution. Oxford University Press.
