The objective of this lab is to teach you the floral parts and to expose you to some of the variation there is in flowers of different plant groups. After this lab you should be able to understand and write floral formulas.
The pictures below were taken from the material display in the lab. We have included a detailed picture of the flower and also the whole plant so you can get familiarized with these plants, their scientific name and the plant family.
For all these specimens you should be able to write the floral formula after having dissected these flowers in the lab.
Flowers are pollinated by different type of abiotic and biotic agents, using your lab book and from your lecture in lab try to infer the pollinators of these flowers.
Please know and identify the following terms: peduncle, pedicel, bract, flower, perfect flower, imperfect flower, symmetry (actinomorphic vs. zygomorphic), perianth, sepal (calyx), petal (corolla),
stamen (androecium) [divided into anther and filament], carpel (gynoecium) [divided into stigma, style, ovary, ovule], placentation [divided into parietal, axile, free central, basal, apical], connation vs. addnation
Ranunculaceae - Clematis terniflora (note cyme)
Phytolaccaceae: Phytolacca americana var. rigida
(clockwise starting at top left: plant, flowers and fruits)
Malpighiaceae: Galphimia gracilis
Alstroemeriaceae: Alstroemeria sp.
Fabaceae: Crotalaria lanceolata
Bignoniaceae: Campsis radicans
On the following plant, do not confuse the showy bracts for petals
Which is the floral symmetry?
Lamiaceae: Monarda punctata
Lamiaceae: Vitex agnus-castus
Asteraceae: Vernonia gigantea
In the following specimen please note the anthers and the hypanthium
Myrtaceae: Melaleuca (Callistemun viminalis)
Lythraceae: Lagerstroemia indica
Notice two types of flowers in this head, actinomorphic flowers are yellow and are located in the center and zygomorphic flowers located towards the outside.
Asteraceae: Bidens alba
Notice the raceme
Plantaginaceae: Digitalis purpurea
Notice purple bracts in the inflorescence
Zingiberaceae: Globba sp.
Check the "corona" in this flower
Passifloraceae: Passiflora sp.
This plant has showy staminodea (=sterile stamens)
Cannaceae: Canna x generalis
In the following examples of orchids notice the bilateral symmetry with one perianth part different from others, and one stamen adnate to style
Orchidaceae: Catasetum pileatum
The flowers of this plant lack a perianth and just the showy stigmas can be observed, this is a dioecious plant and only the carpellate flower/inflorescence are displayed
Euphorbiaceae: Acalypha hispida
This is a trap flower, observe the showy fused sepals
This cactus flower is bat pollinated, notice the numerous stamens, stigmas and bracts
Cactaceae: Hylocereus undatus