Background
Darlingtonia is commonly known as cobra lily due to its startling and special morphological structures. It is dicots, asterids, and found under the family of Sarraceniaceae. Obviously, Darlingtonia is very closely related to Sarracenia which is an allied genus known as trumpet pitchers that is indigenous to the eastern coast of the USA. It is so special with its bulbous green or red heads with a twisted colorful tongue that looks exactly like a cobra. It is native to western Oregon southward to northern California, USA, and in British Columbia, Canada. This carnivorous plant grows in bogs or wet areas with high water tables such as borders of springs and streams. It is commonly found in the acid soil that is peaty or containing high organic matter content especially at a seeping slope near the river or streams.
Morphology
This cobra looking carnivorous plant is herbaceous perennial. It has mainly erected to sometimes decumbent tubular pitcher leaves which grow up to ninety centimeters. The specialized leaves are growing upright that form hollow pitchers which are narrow at the bottom and widen to twelve to fifteen centimeter with a globose hood at the top. The hollow pitcher terminates with a dome or hood from which two flaps of tissue, the projection or appendage, that known as fangs were found from the outside edge of the pitcher opening opposite the ala. Furthermore, The head of the tubular leaf is a puffed hood that has transparent “windows”. Under the hood or “helmet” like structure, a circular opening is found which is difficult to distinguish from almost any angle but below. The colorful tongue emerges from the front portion of the hole which is mustachioed at the opening. It is also known as the “fishtail appendage” that somehow looks like a mermaid tail. Therefore, the whole morphology from a side view is that of a fancied cobra with an expanded hood and protruding forked tongue.
It is a snakelike pitcher that hugging the ground like little tubes with pointy tongues hanging from their ends. These dome pitchers arise from a fibrous-rooted rhizome. Do not be shocked when you saw it, as it would not bite! It has unusual growth features as compare to other carnivorous plants in which they twist gradually just enough as they grow. This is to allow the opening of the pitcher is facing outward from the center of the plant. This may because of diversifying pitchers to multiple angles to increase the chances of attracting and luring insects. If all pitchers are grown in such a way that all are facing inward from the center of the plant, the insects may be confused and have multiple options. Therefore, the pitcher with the hood in darker or attractive red color would have a higher chance to attract more insects than others of the same plant. Besides, the pitchers are mostly pale yellow-green for the upper part and green to darker green for the bottom part. In full sunlight or high light intensity in the greenhouse, it is highly likely to turn red from the yellow coloration of the upper part of the pitcher to attract the prey.
Preying Mechanisms
Most of the prey are flying insects that are lured and rest onto the plant by its colorful, nectar-baited tongue. Besides, crawling insects also in their prey list that following the nectar trails that run up the pitcher’s exterior. Surprisingly, they do catch larger animals such as amphibians and pacific chorus frogs. This may hypothesize that the frog is seeking shelter that tempted to enter the hood by accident. The preying mechanism of cobra lily is a bit tricky. This pitcher acts as a lobster or minnow trap. The two-lobed, apron-like projections, fangs have few pigmentation patterns, mainly green, red-edge, blush, and crimson fangs. The pitcher itself also can be a crimson pitcher that turns completely red during the first season and red keel which is solid red. The coloration helped them to attract insects. The function of the fangs is to provide a landing ramp for the prey (insects). In the preying mechanism, it acts as a nectar-baited tongue that guides the insects to crawl. The fenestrations, translucent areas (dots-like pattern) on the dome, look like an opening to the outside for an insect due to the sun shining through the “windows”. The insect is then climbing up and entered the “brain” of the cobra lily by following the nectar trails that run up the exterior of the pitcher. With the production of nectar, the insect is further lured into the hollow tube which contains a higher concentration of the nectar. The inner bottom lining of this hollow tube containing hairs that are pointing downward which hinders the prey from climbing out. The digestion is aided by the bacterial action secreted by the pitchers which process the insects into a “yummy soup”.
Symbiosis Inhabitants
An interesting fact about this plant is the fluid level of a hollow pitcher increases when the number of victims is added. Other than that, what is found in the hollow pitcher? Well, there are the most striking creatures that live inside the pitcher fluid which are wormlike larvae of a tiny fly that is white in color (Metriocnemus Edwards), which congregate in large numbers around the dead prey in a fashion quite horrible to behold. Sarraceniopus darlingtoniae is another tiny creature that lives in the pitcher which is commonly known as slime mite. The purposes of them living inside the pitcher are unclear, which they may be involved in the digestion process of Darlingtonia.
Propagation and Care tips
Darlingtonia is propagated through the rhizome when it reached maturation. The rhizome sends out stolons from which the new plants develop. It also can be germinated through seeds produced by itself via self- or cross-pollination. When flowering, it has a pendulous on tall scape which has numerous pink-lavender bracts that become papery and abscise. After that, the ovary of the flower will mature and turn into a dry fruit containing seeds that mature about two months later. The hobbyists often propagate it through cuttings of the rhizomes, splitting of the baby pitchers (crown division), or stratify the seeds prior to germination. It can also be propagated by leaf pulling like Drosera and Venus flytrap. For the home growers, one must make sure the cold water runs over the roots that mimicking nature where is it found. Horticulturists used a water chiller or toss several ice cubes on the substrates (sphagnum moss) to create a recirculating and cold-flowering environment.
References and further readings
Schnell, D. E. (2002). Carnivorous plants of the United States and Canada (No. Ed. 2). Timber Press.
Swenson, A. A. (1977). Cultivating carnivorous plants. Doubleday.
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. (Eds.). (2018). Carnivorous Plants: physiology, ecology, and evolution. Oxford University Press.
