Lab 13: Blueberries and Dogwoods


Go to last lab (Mustards) Go to next lab (Gentians) Go to lab syllabus


101. & 102. Ericaceae, the Heath or Blueberry family (including Monotropaceae, Pyrolaceae):
Diagnostic family characters
Leaves: Typically coriaceous, evergreen, alternate and simple
Flowers: More or less pendulous, except in Andromeda, Kalmia, and Rhododendron. Pollen disperses from terminal pores in anthers.
Fruits: Capsules or berries
Habit: Acidophillic shrubby plants with mycorrhizal roots. Look for this family in crappy soils, generally sand or peat.

Key out species 101: Vaccinium angustifolium
Individuals of this genus are extremely brittle in the wintertime. Note the inferior ovaried berries.

Key out species 102: Gaylussacia baccata
May be confused with species 101 in the field look for the texture of the leaves (less coriaceous), the presence of resin dots, and 10 rather than 5 locules in pistil.


103. Cornaceae
Diagnostic family characters
Leaves: opposite except in one aptly-named species (specific epithet alternifolia), arcuate veins with vessel elements containing strongly coiled wall thickenings that unravel to form threads between broken leaf halves.
Flowers: actinomorphic.
Fruits: berries, whitish in some species and much beloved by native songbirds.

Key out species 103: Cornus foemina (=C. racemosa)


104. Polemoniaceae
Diagnostic family characters
Leaves: Opposite and simple in the most diverse genus in our flora; one genus has alternate, pinnately compound leaves. Exstipulate in all cases.
Flowers: perfect, hypogynous, usually showy, tube-shaped or salverform. In the most diverse genus in our flora, the stamens are inserted at different levels within the flower.
Fruits: three-valved loculicidal capsule
Plant: usually with a noxious odor, if you were to cross-section the stem you would see that the vascular tissue forms a continuous ring.

Key out species 104: Polemonium reptans



105. Sarracenia purpurea (Sarraceniaceae) 'Pitcher plant'
This perennial insectivorous herb grows in marshes or bogs nutrients are limited in availab6 It gets nutrients by digesting insects that fall and drown in its pitcher-shaped leaves. The leaves are filled with a dilute solution of acid and enzymes. The large, solitary flowers have an interesting style with an expanded apex that covers the top of the flower like an umbrella. The specific epithet, purpurea, may be in reference to the leaves turning a dark red in some individuals. Why don't insects just crawl out of the pitcher after they fall in?

106. Primula meadia [formerly Dodocatheon meadia] (Primulaceae) 'Shooting star'
The deeply cleft lobes of the corolla are reflexed back giving it the shooting-star look. It is similar morphologically to the Cyclamen (also in the Primulaceae) displayed in lab. Linnaeus originally named the species in Dodecatheon after an ancient Hellenic religion, the Dodecatheon; consisting of twelve Olympian gods and the pantheon of demons and heroes - why? nobody seems to know.



107. Monotropa (Ericaceae, former Monotropaceae) 'Indian pipe'
This genus of non-photosynthetic plants was once placed in its own family along with similar non-green plants. Monotropa uniflora has a single flower per stalk. It is related to Hypopitys monotropa ('Pinesap' formerly Monotropa hypopithys) with several flowers per stalk. They are parasitically dependent on mycorrhizal fungi. Some sources claim that Native Americans used them for medicinal and/or narcotic purposes, hence the common name. A contemporary website offers M. uniflora essence for the purpose of “expanding awareness of the presence of universal love.”

108. Pyrola (Ericaceae, former Pyrolaceae) 'Shin-leaf,' 'Wintergreen'
This genus of low, perennial, evergreen herbs is common in damp and shady woods throughout the U.S. Like the Monotropaceae, the Pyrolaceae has been subsumed into the Ericaceae on molecular phylogenetic grounds. The leaves are found near the ground at the base of the erect, long-peduncled raceme.

109. Impatiens (Balsaminaceae) 'Touch-me-not,' 'Jewelweed'
Both the native and non-native species of this genus are often cultivated for their interesting, strongly irregular, spurred flowers. Then tend to be found in wet areas. The common name, 'Touch-me-not,' comes from the manner in which the capsule fruits of some dehisce explosively when touched or jarred. These plants often have a “juicy” look to them. The juices from the stems and leaves are thought to alleviate the irritation from poison-ivy and stinging nettles.

110. Phlox (Polemoniaceae) phlox

This genus has opposite leaves and may be confused superficially with Dames' Rocket (Hesperis) in the Brassicaceae, but the latter has 4-merous flowers without fused petals. We have several species native and at least two that are often used as ornamentals. Phlox divaricata (woodland phlox) is a common species at exam time in spring woodlands. Phlox pilosa (prairie phlox) is one of our more showy prairie species.