The inner surface of the pitcher is divided into four zones based on the function and structure of the surface. These four general zones are common to all species of Sarracenia. The first zone encompasses the area on the undersurface of the hood. It is called the attractive zone and contains the nectar glands intermingled with stiff, downward pointing hairs which direct the insect's movement toward the bottom of the pitcher. Zone 2, containing numerous nectar-producing glands, is smooth and is located just below zone 1. The digestive glands are located in the smooth waxy walls of zone 3. While the first two zones offer a precarious foothold for the insqct, zone 3 offers none. Moving downward in the pitcher, zone 4 is distinguished from zone 3 by the appearance of downward pointing hairs. This is the digestive and absorptive area. The digestive enzymes and bacteria in the fluid in this region of the pitcher are responsible for digestion of prey. The function of the downward pointing hairs in this zone is to prevent prey from leaving the fluid. Indigestable insect remains are often found as a blackened mass in this region at the end of summer. (Fig. 3-2)
Presumably, luring of prey is accomplished by secretion of nectar, coloration, odor, and fenestrations of the leaves. (Photo 3-2) Although not all of these enticements are
THE PITCHER PLANTS
utilized by every species, secretion of nectar is universal among Sarracenia. In fact, in some cases the nectar secretion is so copious that the nectar is found in globules, particularly in zones 1 and 2 of the pitcher. Nectar glands occur on the outside surface of the pitcher, the upper inner surfaces of the pitcher and hood, as well as on the floral parts.
After an insect discovers the nectar and begins feeding on it, it will work its way to where the nectar is most abundant, in the vicinity of the pitcher's opening. As the insect feeds on the nectar produced on the rim of the opening, it may be enticed into the pitcher by the accumulation of nectar on the surface below the rim, inside the pitcher or along the underside of the hood. On the underside of the hood nectar glands are intermingled with hairs which point down toward the bottom of the pitcher. These downward pointing hairs do not provide a stable footing for the insects. It almost seems that some insects sense the possible danger and, rather than attempt to walk on the hairs, will stand on the rim and stretch as much as possible to reach the nectar. In the process they may lose their balance and tumble to the bottom of the pitcher. Other insects will attempt to carefully work their way around the hairs, feeding on the nectar, unaware that the path they are taking is leading them to the bottom of the pitcher. It is much easier for the insects to walk in the direction that the hairs are pointing than to walk against them. If the insect continues, it will reach zone 2 which, being smooth and waxy, offers no foothold. Hence, the insect falls to the bottom.
Sarracenia minor, S. leucophylla, and S. psittacina have visual lures known as fenestrations to attract insect prey. (Photo 3-3) Fenestrations are areas located on the hood and/or upper part of the pitchers which lack pigmentation and thus are translucent. The fenestrations allow light to enter the pitcher. Insects are apparently more likely to enter the lighted pitchers than if they are dark. When an insect reaches the rim it may see these translucent areas and, believing them to be openings, will fly from the rim to one of these "openings," only to smash into the fenestration and tumble down to the bottom of the pitcher. Alternatively, insects feeding on the nectar may follow a path which leads them to one of these "openings." Once there, the insect usually has no recourse, but to continue down into the pitcher because to get back to the rim it must walk against the pointed hairs.
Words cannot adequately describe the behavior of insects as they feed on the nectar and are unwittingly led to their death. At times during their feeding, the insects stop their activity as if they sense something ominous.
There is a simple way to observe and study insects as they feed on and become trapped in the pitchers. A plant or preferably a single pitcher is covered with a transparent container, such as a wide mouth gallon mayonnaise jar, bell jar, or a plastic bag. A single pitcher is more suitable than a whole plant because if a whole plant is used, a larger container is necessary. Also the insect has more plant area to investigate and, therefore, it may take longer for the insect to settle down and the activity of the insect may be harder to follow. A pitcher should be selected which has a relatively large supply of nectar. The nectar appears on the pitcher as small droplets of liquid which are sticky to the touch. Sarracenia produce the most copious nectar flow in the spring of the year. Often in the fall and winter the pitchers are devoid of nectar.
The pitcher is anchored in a vertical position in a pot of sand or soil and covered with a suitable container. This entire set-up is placed in a sunny area, but not in direct sunlight because the temperature inside may become excessive. (Fig. 3-3)
Now the set-up is ready for insects. We have used houseflies, honeybees, ants, millipedes, centipedes, hornets, grasshoppers, and small beetles. The fastest results are obtained with honeybees, which may be trapped within 10 minutes. The live, captured insect is put in a container which, in turn, is placed in a freezer for 3-5 minutes. This treatment slows the activity of the insect so that it can be handled easily. Care should be taken not to freeze it. The insect is then placed in the container with the pitcher. Within 5-10 minutes after removal from the freezer, the insect is usually active again. If a hole of suitable size is cut through one side of the pitcher near ground level, the trapped insect will have a means of escape. On one occasion we had a honeybee which was trapped and escaped 20 times in one afternoon. There are numerous variations to the set-up. For example, to follow the activities of an insect more easily with species such as S. flava, the hood can be cut off, thus revealing more of the inner surface. In the case of 5. minor, a small opening may be cut in the back of the hood, enabling one to follow the activities of the insect inside the hood. Sometimes the insect will fly out of this opening but this may be prevented by taping transparent material over the hole.
The bottom of the hollow pitcher, zone 3, is lined with glands which secrete digestive enzymes and zone 4 with absorptive glands. These enzymes are effective in the chemical breakdown of prey, except for the more resistant portions of the insect's body, such as chitin. Numerous organisms exist and thrive in the liquid that accumulates in the base of the pitchers. Among these denizens are yeast cells and bacteria which assist in the digestion of the prey, although the full extent of their role has not been ascertained. In any case, digestion does occur and protein is broken down into amino acids, which are absorbed by the plant along with minerals. The efficiency of Sarracenia pitchers is attested to by the numerous insects and their remains that accumulate in the base of the pitchers. Some of the more common victims are ants, beetles, crickets, wasps, spiders, flies of various kinds, and occasionally small toads.
While Sarracenia is famous for its carnivory, not all insects succumb to the lures which lead most prey to their death. In fact, many insects feed on the plants' pitchers and rhizome, while others live in the fluid bath and still others make use of the pitchers to capture insects in their own way and for their own use.
One of the most intriguing members of Sarracenia society is a group of moths of the genus Exyra. Depending on the species, they lay one or more eggs in each pitcher. If more than one egg has been laid in the pitcher, upon hatching, one of the larvae will kill the others or drive them off so that only one larva of the species remains per pitcher. Thus, a single plant with five pitchers supports a maximum of five larvae. Another species in this group lays its eggs in the area surrounding the mouth of the pitcher. When the eggs of the moths hatch, the emerging larvae eat the superficial tissue of the pitcher, causing eaten areas to become translucent.
Eggs from another species of Exyra hatch into larvae which feed on the pitcher walls and produce a tent of silk. Members of this group often spin a net or webbing across the opening of the pitcher, forming a home with protection against rain and other insects. An even more ingenious species of Exyra forms a home for its eggs in a unique way. Shortly before the larva pupates, it eats the superficial material from a narrow zone encompassing the whole circumference of the inside of the pitcher, at about one third the distance from the bottom of the pitcher. This results in a groove being produced, in effect girdling the pitcher. The pitcher above this groove dies, dries out and becomes somewhat leathery. Since the grooved area of the pitcher is considerably weakened because part of the wall has been removed, the weight of the pitcher above the groove, aided by wind, will cause the pitcher to fold over, effectively barring rain and unwanted visitors from the pitcher chamber.
Larvae of another species of this group of moths plan ahead for their escape after pupating into a moth by eating an opening in the pitcher wall through which they can escape. Another hole is eaten below the escape hatch so that if rain enters the chamber, it will not flood because the water can drain out through the lower hole. This group of moths, whose larvae not only use the pitchers as a dwelling place but also derive nourishment from the tissues of the walls, does not limit its appetite to the pitcher but will also devour the flower and even the rhizome.
Creatures such as spiders inhabit the mouth of the pitcher and some build webs and catch prey in the mouth area. Often the web will completely cover the opening. We have observed a small toad waiting just outside the mouth of the Sarracenia purpurea pitcher for some prey to come along.
The caterpillar (larvae) of Papaipema appassionata lives on rhizome tissue that it bores out of Sarracenia rhizomes, thereby forming hollow tubes. This larvae leaves its tell-tale evidence at the surface, a pile of debris which is colored light brown, granular, and resembles earthworm castings.
SPECIES OF THE GENUS SARRACENIA Species
S. leucophylla var. alba** S. minor S. oreophila** S. psittacina
S. purpurea ssp. purpurea
S. purpurea ssp. purpurea f. heterophylla
S. purpurea ssp. venosa
S. rubra ssp. rubra
S. rubra ssp. alabamensis*
S. rubra ssp. gulfensis
S. rubra ssp. jonesii
S. rubra ssp. wherryi
Alabama Canebrake Pitcher Plant. Species designation is being contested at this time. Some taxonomists feel it is a subspecies of S. rubra.
The Pale Pitcher, formerly named S. sledgei. Huntsman's Horn, and Yellow Pitcher. There are at least five color variants in this species.
White Trumpet, formerly named S. drummondii.
The Hooded Pitcher Plant. The Green Pitcher Plant. Parrot Pitcher
Purple Pitcher, Pitcher Plant, and Northern Pitcher Plant. Formerly named S. purpurea ssp. gibbosa.
Southern Pitcher Plant Sweet Trumpet
These two are the same plant. Some botanists consider this plant a species, whereas others consider it a subspecies.
**Species which produce ensiform or winter leaves known also as phyllodia.
S. alabamensis Case & Case. Erect leaves with narrow wings which are trumpet-shaped and reach lengths of 20 in. (51 cm). The orifice is covered with an ovate suberect hood which has wavy margins. Two types of leaves and occasional phyllodia are produced. Early spring leaves tend to be curved with summer leaves tending to be straighter and usually larger with a more pronounced taper. The pitcher is green with maroon venation and in strong light has a reddish hue. Faint fenestrations or areoles are present.
Scapes tend to be a few inches (cm) taller than the pitchers and bear reddish-colored flowers. Plants flower in April and May.
S. alata (Wood). Leaves are erect, trumpet-shaped usually with a narrow wing, and measure up to 35 in. (89 cm) in length with a suberect ovate hood with a flat or slightly revolute edges. Leaves usually appear at flowering or shortly thereafter. Pitcher color varies from greenish to pale yellow and in strong light there is red to purple veining with diffuse red coloration on the upper part of the pitcher. Few, if any, sword-shaped ensiform phyllodia are produced. When present they are usually less than 2k the length of the summer leaves. Flowers vary from yellow to whitish yellow color and have a
musty odor. Scapes may reach heights of 30 in. (76 cm). Plant blooms about mid-March.
S. flava L. Summer leaves are erect, trumpet-shaped with a wide flaring orifice subtended by a rounded hood which is almost flat with revolute edges and has a prominent keel. The leaves can reach lengths of 39 in. (99 cm) and those produced after flowering have a narrow wing. Numerous sword-shaped ensiform phyllodia which are usually 20 in. (51 cm) or less in length are produced during late summer and winter. Leaf color is quite variable ranging from light green to yellow with red splotches and in some plants the whole pitcher is a solid red or maroon color. Often there is red or maroon venation in the leaves. Flowers are bright yellow color and have a pronounced musty odor. Usually it is the first Sarracenia to bloom in a given location. Blooming starts in mid-March at the southern limit of its range to mid-May in North Carolina. Scape is shorter than the summer leaves.
S. leucophylla Raf. Leaves appear at the same time as flowers and measure 37 in. (94 cm) with a narrow wing. They are trumpet-shaped with an erect to suberect ovate hood with wavy margins. This plant is distinguished from other Sarracenia by extensive white coloration of the upper part of the pitcher. The distinctive leaves are mistaken for the bloom. There is red or green veining in the white area with a red or maroon suffusion. In late summer and fall a few ensiform phyllodia or ascidiform leaves with greatly reduced pitchers are formed. Scapes are usually shorter than the leaves and red to maroon-colored flowers are produced which have a sweetish odor. Flowering takes place from March to April. The upper V2-2/3 of the leaves of var. alba are almost solid white with red venation.
S. minor Walt. Leaves are up to 28 in. (71 cm) long, gradually expand from base to orifice, are erect and have a wing which is widest in the middle. An ovate hood arches closely over the orifice. The leaves appear before flowering. Pitcher color is mainly green with a coppery red and/or yellow coloration in strong light. There are numerous fenestrations on the upper part of the pitcher. No phyllodia are produced. Flowers which are yellow color and odorless are borne on scapes which are shorter than the leaves. Flowering occurs from mid-March to mid-May.
S. oreophila (Kearney) Wherry. Summer leaves appear before or at flowering, usually have no wing and measure 30 in. (76 cm) in length. The trumpet-shaped leaves have a suberect rounded hood whose base is strongly constricted, colored green to yellow-green with a diffused red or maroon coloration in strong light. Ensiform, falcate phyllodia are usually less than 20 in. (51 cm) long. The numerous scythe-shaped phyllodia are characteristic of this species and distinguish it from S. flava and S. alata, the two species often confused with S. oreophila. These leaves are produced during late summer and fall. The flower scape is as long as the summer leaves. Flowers are greenish yellow to yellow color and bloom from mid-April to early June. The lack of odor and the lighter color of the flower helps to distinguish it from S. flava.
S. purpurea ssp. purpurea Wherry. Pitchers which may reach lengths of 18 in. (46 cm) are curved, decumbent to ascending with considerable expansion at the orifice which is not covered because the hood is erect. The hood has prominent lateral wings and the edges are wavy. Pitchers are green in shaded habitats, otherwise they have varying degrees of red or maroon variegation. In full sunlight the plants are often a solid red or maroon color. Flowers which are borne on scapes that may reach lengths of 28 in. (71 cm) vary in color from yellowish green to shades of maroon to light pink. Flowering is from March to May.
S. purpurea ssp. venosa Raf. This plant is similar to Sarracenia purpurea ssp. purpurea except that its pitchers are shorter and wider and their exterior surfaces tend to be pubescent. This subspecies occurs in the southern portion of its range whereas S. purpurea ssp. purpurea exists in the northern part. The distinction between these subspecies is not clear where their ranges merge in the New Jersey, Pennsylvania and Carolina regions.
S. purpurea ssp. purpurea f. heterophylla Eaton. Plants are the same as S. purpurea ssp. purpurea except they have no red or maroon coloration in the pitchers or flowers. (Photo 3-4)
S. psittacina Michx. Evergreen leaves 2-12 in. (5-30 cm) long are usually decumbent forming a basal rosette. The wing is 0.4-1.6 in. (1-4 cm) wide, being widest near the fenestrated globose hood. The orifice or opening is small, round and has a collar. Leaves are green with varying degrees of red to purple coloration the extent of which is determined by light intensity. Flowers appear from March to May. Flower color ranges from red to maroon with lighter areas often appearing on the ends or throughout the petals. Scapes vary from 4-14 in. (10-36 cm) in length. (Photo 3-5)
S. rubra ssp. rubra. Pitchers are erect, have a narrow wing and are dull green with a profuse reddish to purple veining near the upper part of the pitcher. This is the smallest of the erect Pitcher Plants with the narrowest pitchers having a rather uniform expansion of the pitcher. Sometimes there is a difference between the early leaves of the season, often called spring leaves which are curved, whereas the later or summer leaves tend to be straight. An ovate, suberect hood arches over the orifice of the pitchers which may measure up to 11 in. (28 cm). Scapes are taller than leaves reaching lengths of 22 in. (56 cm). Flowers are sweet-scented and of various shades of maroon. It has been reported that a yellow flowered variety has been discovered. Flowering takes place from mid-April to June.
S. rubra ssp. jonesii. The pitchers are longer, 28 in. (71 cm), than those of S. rubra ssp. rubra with a more pronounced expansion of the pitcher near the orifice. The hood is higher over the orifice and the hood is wider than in any of the ssp. of S. rubra. The veining is much more prominent and there are faint areoles on the pitchers.
S. rubra ssp. wherryi. Very closely resembles S. alabamensis. Its hood is shorter than that of S. alabamensis and almost as long as wide. The pitchers have faint areoles and more venation in the area of the orifice and column and are 18 in. (46 cm) long. The pitchers are dark green whereas in S. alabamensis they are yellow-green.
S. rubra ssp.gulfensis. This subspecies has the longest pitchers, 26 in. (66 cm), which proportionally do not expand as much as the pitchers of other ssp. The external veining is darker and more prominent, whereas the internal area of the orifice and column is less developed.
Listed below are the simple Sarracenia hybrids. Since Sarracenia hybrids cross very easily with each other, producing viable seed, there are numerous crosses between hybrids and between hybrids and species.
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