|
Go to last lab (Mustards) Go to next lab (Gentians) Go to lab syllabus
101. & 102. Ericaceae
Diagnostic family characters
Leaves: Typically coriaceous, evergreen, alternate and simple
Flowers: More or less pendulous, except in the Rhododendroideae (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.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 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
SPECIES TO LEARN:
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. Dodecatheon meadia (Primulaceae) 'Shooting star'
This is such a beautiful flower that a picture of a close relative features prominently on the homepage of this course. 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) that is on your table. As to why Linnaeus named this genus after an ancient Hellenic religion, the Dodecantheon; consisting of twelve Olympian gods and the pantheon of demons and heroes, nobody seems to know.
GENERA TO LEARN:
107. Monotropa (Monotropaceae) 'Indian pipe,' 'Pinesap'
This genus of non-photosynthetic plants is now placed in the Ericaceae family. It consists of two species, Monotropa uniflora, with a single flower per stalk, and M. hypopithys, with several flowers. 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 (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. Find the prominent declined style. Can you think of any advantages of having this overall shape?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. Find some characteristics that will help you distinguish this genus from others we have looked at with zygomorphic flowers.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.