A study of a pitcher plant (Sarracenia purpurea) population in a peatland of southern New Hampshire
Marc Sudman
Department of Biology
Abstract--A population of pitcher plants, Sarracenia purpurea, was investigated over a one month period beginning on 17 May/99. I marked a total of 83 colonies of S. purpurea
and collected demographic data. A total of 134 plants were investigated and both
inflorescence and new growth phenology were noted. At the end of the
investigation, 15 Jun/99, new growth were still forming and several plants were
still producing flowers. This paper will provide quantitative data concerning
this previously uninvestigated population that will serve as a platform for
future investigations. An addendum to this paper provides general and anecdotal
observations made during this investigation. A portfolio of ca. 30 pictures
documenting new growth forms/stages, inflorescence stages and development, and
various other images accompany the text. Introduction New England College’s Peatland Research Project has been investigating the biology of the carnivorous, northern pitcher plant, Sarracenia purpurea. During these investigations, many observational, qualitative, and anecdotal data were collected. These studies included investigations into the inquiline community taxonomy, winter dormancy conditions, and effects of late autumn and hibernal flooding on the inquiline community and dormancy breaking plants, to name a few. The entire population, though, had yet to be quantitatively described and no attempt had previously been made to spend any "quality" time with these plants at this site. The population studied inhabits a small peatland. This peatland has been the study site for NEC’s Peatland Research Project. Preliminary hydrogeological investigations suggest that this site is an oligotrophic, level, quaking peatland. Indicator species of both fen and bog compositions are present so it might be said that this peatland is a poor fen (but for those whom enjoy the colloquial term bog, this site can then be called "bog-like). This site consists of an entire sphagnous mat (dominated by Sphagnum magellanicum, IDed by Charlotte Mallio) surrounded by a small moat. There is no open water, although in some areas of the peatland the moat can extend considerably onto the mat causing seasonally fluctuating standing water. The sphagnous mat is dominated by Ericads (Kalmia polifolia, K. angustifolia, Andromeda glaucophyla, Chamaedaphne calyculata, Vaccinium macrocarpon) with occasional eastern white pine (Pinus strobus), tawny cotton grass (Eriophorum virginicum), and sparse sedges (Carex spp.). Ericacious cover is highly variable throughout the site; some spots of the mat consist of a considerable ericacious root system, while other spots consist of only sphagnum. The population of S. purpurea inhabits ca. 1/3 the area of the quaking mat. Because S. purpurea has a 10cm. average seed dispersal distance (from conversations with Aaron Ellison) and animal aided dispersal (via feces droppings) has yet to be confirmed, it comes to no surprise that the plants are found in patches throughout the site. It is unclear how the population was introduced into this site but it is presumed to have occurred by animal aid. Methods Beginning on 17 May/99, daily visits to the plants were made. During each of these visits, time was spent with each plant. Because demographic data do not change from day to day, different data were collected during each visit; on some days only a partial visit to the population was made. Prior to this investigation, ca. 63 of the plants had been tagged and flagged. On 20 May/99, all plants were assigned new tags and over the next few days a total of 83 plants (colonies) were tagged. About 20 plants were marked with a bamboo shoot 50 cm. high with a length of glo-pink tape attached to the top of the shoot. At the plants without a bamboo shoot, glo-pink tape was tied to surrounding flora. Numbered, aluminum dog tags were fastened to the tape at each plant. During visits to individual tags, several data were collected: Number of plants (Table 1) - Because it is difficult to determine the number of plants based on pitcher number and orientation, several methods were used to determine number of plants per tag. Some colonies could be explored by gently moving sphagnum out of the way and observing number of root apices. Some colonies were explored by feeling for root apices. At tags with more than one inflorescence (both present year’s and last year’s), the number of inflorescences was used as an indication of number of plants. Both root apices and inflorescence # were used as an indication of the number of plants present at a colony. Number of pitchers - The total number of pitchers was counted and a determination was made on the number of actively trapping pitchers. Those pitchers that were filled with water to ca. half the pitcher volume were counted as actively trapping pitchers. The remaining pitchers were either chewed upon, drained of water, buried in the sphagnum, or moribund. Although the title "actively trapping pitchers" suggests that the plant is producing nectar and/or utilizing prey nutrients, the term is used primarily to distinguish healthy pitchers from dead or dying pitchers and possibly to determine age of pitchers. Phylodia (Table 2) - Presence of phylodia was noted on those plants at which clear and obvious, non-functional pitchers were observed. Because of their often small size and non-rigid characteristic, phylodia are difficult to see amid the sphagnum and no effort was made to uncover all phylodia present. For this reason, phylodia data are not exhaustive. Inflorescence (Table 3) - Inflorescences are easily observed extending above the sphagnum. Several traits were observed and noted for phenological data. Phenological events relative to flower development were investigated during this investigation, and the following characteristics were observed: height of inflorescence
- This was measured from the point of inflorescence attachment on the root apex to the torus flower orientation
- This was determined based on the orientation of the flower head. Those flowers with the umbrella-shaped style positioned parallel to the ground are considered nodding; those flowers with the umbrella-shaped style positioned perpendicular to the ground are considered upright. flower stages
- Flowers go through several stages during their development and reproductive behaviors. Initial observations were to distinguish a flower bud from a mature flower. A bud was noted if the sepals and bractlets were completely closed around the flower parts. Buds were tight spheres just until flower opening and hence easy to distinguish from open flowers. Open flowers were noted in several developmental stages. After sepals had opened, the position and/or presence of the petals was noted. Those petals still enclosing the pistil were noted as not dropped; those petals that were positioned so that the pistil was exposed were noted as dropped; those petals that had separated from the receptacle and fallen onto the ground were noted as fallen". Stamens were also noted as being attached to the receptacle or separate from the flower (the stamens are hypogynous and this should not be confused with the observation of them being separate from the flower; the term "fallen" was used to denote the occurrence of the stamens completely falling from the flower and dropping onto the style or onto the ground). New Growth - New growth pitchers were noted when observed. Because of its small size early in the season, many of the new growth were not visible until later in the investigation. Minimal effort was made to uncover new growth because of the amount of disturbance that would be necessary to uncover all new growth in the early stages of development. For this reason, new growth data are not exhaustive. Presence of new growth, length measurements, and morphological observations were noted over the entire investigation. Phenological events relative to pitcher development were investigated during this investigation, and the following characteristics were observed: length
- The length of developing pitchers was approximated to minimize disturbance. This approximated measurement was made from the apical region of the petiole to the tip of the pitcher. Approximation were made because of the frailty of the new growth during it development and because many of the new growth were partially or entirely buried in the sphagnum which made it difficult to see the petiole region stage of development
- Pitchers change shape during their development. This shape (form) was noted throughout the investigation. Those new growth that were lanceolate, did not show any pitcher hood form nor wing formation, and appeared rigid were noted as "not formed"; those new growth that were beginning to show form at the pitcher head (crease) and showing wing formation were noted as "barely formed"; those new growth that were beginning to swell, and had noticeable wing and hood formations were noted as "slightly formed"; those new growth that showed marked swelling, a distinct hood and wing, and were
predominantly green were noted as "mostly formed"; those new growth that were absolutely pitcher like with a lumen, revolute hood, and complete wing were noted as "formed". New growth that were formed but not open were noted as "just formed"; those that were observed to be opening were noted as "beginning to open"; those that were observed to be about to open were noted "about to open"; those that were observed to be open were noted as "open". Mapping - Mapping of individual tags was accomplished using a Redi-mapper. A distance and a compass bearing from each tag to Pine 3 (this pine is already mapped) were taken. These data were then used to construct individual plots on a Redi-map disk. These disks were then scanned into a picture-publishing program and individual plots were numbered and overlays were made. Temperature/RH (Table 5) - On 27 May/99, two HOBO Pro Temperature/RH Data Loggers were placed in the peatland. Each logger was first attached to 1”x2” untreated pine wood stake. The logger was cased in a plastic container similar to the containers that deli stores use for cole slaw and other salads. This container serves to inhibit direct contact with precipitation and to protect the loggers from animals. A 1mm. wire screen was then placed over the aperture of the container to inhibit possible insect inhabitants. The loggers were both launched on 27 May/99 with a delayed start time of 1200 28 May/99. The loggers were set for 12-bit high-resolution temperature measurements at 30 minute intervals (both temp. and RH). This resolution and interval scheme will allow for ca. 420 logging days. Logger 1 was mounted at a height of 1.5m on a white pine. This white pine is located 6.12m from Pine 3 at a bearing of 27° SE. This logger will allow for ambient temperature and RH measurements that should correlate with general air temps. and RH. Logger 2 was placed at a height of 7cm above the sphagnum mat. This position is 3.84m from Pine 3 at a bearing of 19° SE. This logger will allow temperature and RH measurements of the conditions to which S. purpurea are subjected. pH (Table 6) - On 9 Jun/99, peat samples were collected from the site and brought back to the lab for analysis. There were periodic rains the night before and the mat was saturated with water. These samples were collected from a depth of ca. 10 cm. below the surface the of the peat (peat surface determined by base of sphagnum). This is where most of the Sarracenia root system resides. All samples were collected by hand-digging to preferred depth. Peat clumps were excavated, placed in 50 ml glass vials and capped. Samples were immediately returned to the lab for analysis. Tables
Independent research project
Jun/99
These individual, field moist peat samples were weighed to 15g (14.97-15.02 g) and placed into 150 ml containers. 30 ml of deionized water was added to the peat and this mixture was shaken for a few seconds until a slurry formed. The cap was removed and the slurry sat undisturbed for 30 minutes before readings were made.
An OAKTON pH/mV/°C METER was used for pH readings. The meter was standardized/calibrated at pH 7 & 4. Readings were made by tilting the container of the slurry at an angle so that adequate solution was available to ensure complete submergence of the electrode. The probe was gently swirled in the slurry until the meter stabilized, at which pH and temperature were recorded.
Table 1 - Listing of number of plants, pitchers, and trapping pitchers. Column "PPs" indicates number of pitcher plants; column "Ps" indicates total number of pitchers; column "TPs" indicates number of trapping pitchers.
Table 2 -Summary of plants with phylodes
Table 3 -Summary of individual plant phenology. Key: "bud"-closed flower bud; "nodding"-flower nodding; upright-flower perpendicular to ground; "f"-flower; "p"-petals; "pnd"-petals not dropped; "pbtd"-petals beginning to drop; "pd"-petals dropped; "pf"-petals fallen; "sf"-stamens fallen. Unless noted, all open flowers are nodding and all buds are upright.
Table 4 -Summary of individual pitcher phenology. Key: "nf"-not formed; "bf"-barely formed; "sf"-slightly formed; "mf"-mostly formed; "f"-formed; "bto" –beginning to open; "ato" –about to open; numerals denote new growth length in cm..
Table 5 -Temperature/RH
data not available
Table 6 -Summary of pH readings.
General and anecdotal observations
A field notebook (scribble pad) is an invaluable resource for the field scientist and natural enthusiast. For a field scientist, any data/sketches that he finds helpful in describing what is encountered while in the field are scribbled in the pad . For an outdoor enthusiast, any words/images that the he finds helpful in describing what is encountered in his mind are scribbled in the pad. Some find it difficult to distinguish between the two. I have included some of those words from my field notebook that offer description in a way no ‘data’ can. The following words are verbatim ac litteratim as scribbled in my pad; by doing this I have refrained from scientific editing and literary embellishment. Some of the following passages/notes describe the flora & fauna contained in the above sections and the work associated with producing these data; some do nothing but describe. . . |
17 May/99 930
-Ahhhhh. . .!
The weather’s fine for my 1st day at this project. Developing this project, hypothesis & M&M (overall design), was purely theoretical. Now I begin the field work. I expected to find, and still do expect to find, great distances between the earlier paper submitted & what will go on in the field. Other than Deb’s concern that spiders will not be found in the apertures, there has been no input or discussion about the design, variables, hypothesis, etc.. Deb’s interests: descriptive, demographic field work. Today I visited each plant with a tag (almost all). They don’t look so good. There are many pitchers that appear to have been chewed upon, both the hood and holes in the pitcher. Many pitchers are entirely dead (moribund/brown) and many contain no water. 1st year (new) pitchers are just beginning to show form. Most are still rigid protrusions from the base of the rosette (?) & those showing form have only an enlarged tip. The inflorescence buds are noticeable as ca. 1.5cm balls extending maybe 2-3 inches from the base. Several plants have inf.. buds at their base but the buds have been removed. I need to study growth stages and the development of the plant’s anatomy.
18 May/99 900
-My dove friend was on the electric wires by the fence but I did not see her in the bog!
19May/99 1000
-I’ve removed our old access point planks. We caused alot of damage in that area. It seems that we caused the moat to extend in to the mat by a good 10ft or so.
-Uh oh, it’s raining. I’ll write later
-I noticed a few small basidiomycetes in the sphagnum by PP51; Maria would be happy to know!
-nectar quantification see -- McKenna, M.A. & J.D. Thompson. 1988. A technique for sampling & measuring small amounts of floral nectar. Ecology 69: 1306-1307.
20 May/99 930
-I’ve renumbered the plants so that I can produce a more logical map. I still have several plants to tag and still others to flag. All data and plant # will be coordinated when all tagging, flagging, locating and switching is finished.
- I noticed an incredible # of B&D webs in the top/end of Ericacious branches. Most of the B&Ds were occupied by 2 spiders. They were all over near PP14 area. Several photos were taken.
25 May/99 900
-Beautiful Cypripedium (pink) on "trail" around SE corner toward perch; forest area! Many photos
-I’ve noticed that many of the inflorescence buds are either removed from the plant entirely or moribund. Many of the buds are found sitting on the sphagnum as though they were carefully removed from the peduncle. Many of the peduncles are seemingly wilted or broken at a joint/bend. So far, all of the buds/infl.. found removed from the plant are ca. 1.0-1.5-2.0 cm across.
- The flower buds are variable in size. PP9 seems to have the largest flowering buds at this time. They appear to be opening (photo). Some are still only several cm. extended above the root apex while some are >10cm.
-I do not plan on systematically quantifying moribund/removed buds nor site of infl. I will continue to record observations.
-most (all) bowl & doily webs are inhabited by
2 spiders.
26 May/99 900
-Today is raining so i’ve decided to get much done in the lab.
-The beetle collected 25 May/99 is possibly a carab beetle (fam. Carabidae). Colby has provided me with several
Order & Family keys to the insects. I need a higher magnification (dissecting scope!)
27 May/99 900
-PP41 - closed off P; entirely brown & closed off w/ paper machete looking barrier; hole at top by which a shitload of ants exited & then entered; upon disturbance!
-I noticed many Wyeomia adults in several Ps. They appeared dead on the surface of the water or flailing about on surface.
-On a P at PP34 I witnessed a nice visit to the P by a fly (housefly). It landed on the top of the hood and proceeded to explore the P. It traveled down on to zone 1 and methodically traversed the zone. It explored the entire zone tracing several paths. it teetered on the boundary between zones 1 & 2. I waited for it to lose its grip on zone 2 & slip into the water, which was ca. 1cm below zone. It didn’t! It made its way on tot he nectar roll & explored the surface. I could see its proboscis (?) moving erratically over the surface of the P. It repeated this venture, not in any pattern though, for ca. 5 minutes until a beetle (same as collected on 25 May/99) landed/crawled onto zone 1. The fly then flew to another P on PP33. I thought I’d witness a trap/capture!. . .
-new growth is variable in size from PP to PP
*could it be related to microhabitat?!?!
-more dead inflorescences
28 May/99 1000
-Wow, it’s hot 2day; yup, hot in NH!
-my first visitors today - M. Mitch & Fernando
3 Jun/99 830
It’s likely to rain 2day. I feel comfortable in the bog when it’s raining. Last time it rained while I was there, I climbed up a fallen pine that was resting on limbs from upright pines/oaks. It made for a nice slanted platform to make my way up toward the higher "ground". Once I had climbed ca. 15 feet above the sphagnous mat, I reclined on the fallen tree trunk and rested there for maybe half an hour.
-There is much be said about "likely". 2day, this morning, was beautiful. The sky opened up & sunshine made it presence. It was hot but was much welcomed! It was humid, it was hot, the mosquitoes & flies & spiders were out in full force, the mat was close to saturated. . .that’s how i like in the bog - Alive!!!
-non-formed new growth (NG) is sword/spear-like, not showing any wing formation but showing a minimal crease at the tip (beginning of hoods?)
-most NG at about 10cm shows some wing formation w/ a more pronounced crease at the tip; appears to have formed a lumen
-formed NG at ca. 10cm or > shows clear pitcher form i.e.. lumen, revolute hood & wing
-open flowers have all sepals separate and petals exposed. Almost all though, at this time, required a line of sight from below to see petals. Also, the bractlets are separate from the sepals
-petals in some are still closed but in others are opened just enough to view the umbrella shaped style (?)
4 Jun/99
-Has the bog acclimatized to my schedule!? I sit here, down w/ the plants, amid the shrubs, available for the spiders & ants, soaking up the sphagnum water on the seat of my pants, so comfortably. Today is Friday, and i’ll give today its developed name as the "end of the weed". As today happens, I await 2night & 2morrow w/ anticipation. has the bog sensed these feelings!? I say this because since I have arrived, nothing but sunshine, a light breeze, & most comfortable temperatures have caressed my skin!!! And some call what I do here in the bog "work"; hardly! I walk away from the bog today, sure to return soon, with such a smile. . .
-I was greeted, on my way into the bog this morning, by 2 splendid Odanata (?). Each was ca. 7cm. long, wings ca. 3-5 cm long. The wings were a translucent black, like looking thru stretched out black panty-hose. At least on one wing was a white dot ca. 3mm across on the upper, rear part.
7 Jun/99 930
-The air is incredibly thick (for New Hampshire; my perspective!) Check the logger data for today, I bet its up there!
-pollen covered webs!!!
-PP5 - NG is fully opened & beautiful! Both are a vibrant, yet soft green color w/ soft crimson veins. They look supple. They are void of H2O. The leaves are soft & delicate looking as opposed to the leathery & weathered old growth. I see 3 open & 2 ca. 10cm f. Seemingly obsequious to the elders!!!. . .
-Pollination, rather attempted pollination, is incredible. My car is covered with pollen but that is "boring". It has been noticed, both spoken about & photographed, that during the early morning hours, when dew formation is possible (temp, rH, etc.), the myriad Linyphiid webs, (& some others) are clearly visible. The dew-laden threads of silk appear to thicken in diameter. I do believe that the H2O coating increases the visibility as well (reflection, spectrophom_effect (?)). But. . .
Today the myriad webs took on a different appearance. The fine, yellow pollen that has been raining down has adhered to the web’s fibers. At a distance, this gives the webs a musty, soft appearance while increasing their visibility. A close up view reveals the thousands of pollen grains stuck to, and in the web. The webs then are a wonderful yellow mesh of thin fibers laden w/ speckles of yellow grain. In addition to this phenomenon, each leaf of Kalmia, Andromeda, Vaccinium, Chamyodaphne & other Ericaceous shrubs, was covered w/ a dusting of yellow pollen. The Sarracenia pitchers also contained a speckled layer on the exterior. What effect might this have on the pitcher fluid & inquiline community as pollen falls into the phytotelmata?!?! The deep, crimson sepals & bractlets of Sarracenia flowers were covered w/ a speckled layer of yellow pollen grains. "Walk me out in the morning dew. . ." or during early summer pollen dispersal. . .a most beautiful phenomenon!!!
8 Jun/99
-Might it be hotter today; i guess my loggers will tell. I sit here atop the sphagnum, still saturated though. Maybe the humidity contributes a bit to the lack of evaporation (slow rate rather). Sphagnum has some capability to resist desiccation! My bum is sure soaked. . .
-Are these inflor. stunted in their height? They are shorter than other plants that I am aware of.
-Sitting over PP5, I could witness many visits to the Ps by Culicids. These are presumably the same sp. as the one collected on 7 Jun/99. These small creatures hover in & out of P openings. Some i’ve seen land & remain still on zone 1 & others, those brave souls, actually wander to zone 2 & 3 if the water level permits. i have spent much time witnessing these visits; not once have I seen a "trap" although i observe dead ones all the time floating on the surface of its grave.
-Is Kalmia angustifolia flowering early
9 Jun/99
-Today was relatively cold. it had rained the night before leaving the air and all things in the bog wet. The rain has cleared away most of the pollen that had covered all surfaces the past week or so. the mosquitoes were in swarms similar to the black fly swarms. Incredible numbers of them. This presence was compounded by the fact that I was crouching down to Sarracenia & shrub level. Although only my hands & head were immediately available to the ladies, the3y managed their way into my shirt to my back. They flittered, rather hovered, around my eyes, nose, mouth & of course my ears & forehead. they pierced each finger, both hand-tops, every spot of my neck & forehead. They must be lived with & tolerated & allowed to feed & hover though. . .
To him who works and seeks in her, Science gives much pleasure--to him who learns her facts, very little. . .a higher culture must give man a double brain, two brain-chambers, so to speak, one to feel science and the other to feel nonscience, which can lie side by side, without confusion, divisible, exclusive; this is a necessity of health.
-Friedrich Nietzsche, Human All To Human
copyright 1999 Marc Sudman