Field notes: Sarracenia purpurea f. heterophylla

Michael.Chamberland (23274MJC@MSU.EDU)
Wed, 05 Jul 95 21:39 EDT

Over the Independence Day holiday weekend I took a five-day trip through
the top of Michigan's lower peninsula to hunt for carnivorous plants,
and to botanize in general. On top of my list of plants to find was
Sarracenia purpurea f. heterophylla, a form of Sarracenia purpurea lacking
the red anthocyanin pigment and characterized by all-green pitchers and
pale yellow-white flowers. This form has been reported from various sites
across the northeastern US and Canada, but is well documented only from
Montmorency County, Michigan.

Guided by Fred Case's 1956 paper in Rhodora, I made my way to Montmorency
Co. and to the bog site listed as "bog 9" in Case's publication. I was
curious to see what changes had occurred since 1956, and whether the bog
even still existed.

At first I had my doubts, as much of the surrounding area has been
converted to farm land, and when I plunged in to the forest the thick
and nearly impenetrable vegetation had the look of a bog grown over and
reclaimed by the forest.

I was not kept in suspense for too long however, before I cleared the
forest I began to find sphagnum -- and pure-green Sarracenia! The forest
opened up into a dry sphagnum bog studded with Larix and and understory
of ericaceous shrubs. The bog WAS wet, but contained no standing water,
and the Larix was alive and growing. This is in contrast to bogs I have
found further south in MI which typically consist of sphagnum hummocks
emerging from water, and usually with dead Larix. This bog was quite
easy to walk in.
The photo in Schnell's _Carnivorous Plants of the US and Canada_ seems
to have come from a different site. The "bog 9" has few of the grassy
monocots which surround the f. heterophylla plant in Schnell's photo.

Sarracenia were numerous but widely scattered in the bog and around the
forest margin, where plants occurred frequently in deep shade. I quickly
noticed that plants with red pigment were present alongside the all-green
forms. The occurrence of these color forms did not appear strongly
correlated with exposure. Pure-green forms could be found in full sun
while red-pigmented plants also occurred in the shade. I did not attempt
to lay a transect and do a count of color forms as a repeat of Case's
study, however the approximate 1:1 ratio of pure-green to pigmented forms
seemed to still hold for this bog. Admittedly, judging a plant to be
"pure-green" was not easy. Green pitchers which had aged or been damaged
often had brown necrotic zones which could be mistaken as red pigmentation.
Those plant which did have anthocyanin pigments tended to show it as thin
red lines along the vascular traces of the leaves. Often these were faint,
and nowhere did I encounter plants which were deeply reddened. All appeared
less red than average for Sarracenia purpurea. Old pitchers which presumambly
lasted through the winter tended to be the reddest, and sometimes the new
growth on such plants was nearly pure green. Then there were plants with
pure green pitchers but with floral bracts that were "sunburned" red or even
variegated with red! I did not see any of the "orange-red" tinted plants
mentioned by Case, but I did see this phenomenon later in the trip while
observing normal forms of S. purpurea. The orange color seems to arise from a
faint suffusion of anthocyanins through the leaf, not confined to the
veins, but not concentrated enough to turn the entire leaf red.

The pure-green plants did not look yellow-green, nor were they deep verdant
green as in some photos of cultivated specimens. Instead they appeared to
me as pale light-green, so pale as to make the traps look rather delicate
and translucent. It may all be in the lighting.

I was almost too late for flowers. The big styles were draped with
little strips of tissue paper -- the remains of dried petals.
When I did find a flowering individual the petals tended to be red to
pinkish-red. After much searching I found one plant with an intact
flower with pale yellow-white petals. I dedicated a good portion of a
roll of film to this plant.

Also present in the bog was Drosera rotundifolia and specimens of
Andromeda glaucophylla as glaucous blue as the succulent Senecio ficoides!

This bog is well protected by the most vicious squadron of mosquitoes I
have yet encountered! Sarracenia purpurea f. heterophylla is listed as
Threatened under Michigan's Endangered Species Act of 1974, so I did not
collect a plant even to supplement MSC's single representative specimen.
No seed pods were evident, although seeds were plentiful on typical
S. purpurea elsewhere in upper Michigan.

Michael Chamberland