Laboratory 3: Reproductive Characters

Objectives for this lab are to:
  • become familiar with a dissecting scope and its features
  • learn definitions for reproductive terms (look for bold words in this lab)
  • learn to identify and count the parts of a flower
  • learn to interpret floral symmetry, fusion of floral parts, and ovary construction
  • learn to write and interpret floral formulas
  • learn inflorescence types
  • learn fruit types
  • practice keying skills
Safety concerns for this lab:  Use caution with dissecting tools, wear goggles if working with specimens preserved in Carosafe, dispose of Carosafe specimens in proper waste container

This lab covers the reproductive parts of flowering plants--flowers, fruits, and seeds. This lesson can be divided into two parts: Most of this material is linked to images; some is not. This topic is covered fully in Vascular Plant Taxonomy by Walters and Keil. 

Basic Concepts

Parts of a Flower

Ovary Position

Floral Symmetry

Perianth shape (usually applied to corolla, but may be applied to calyx)

Rotate--shallow and relatively flat or dish-shaped
Stellate--star-shaped  (this is not as commonly used as some other terms)
Urceolate--urn-shaped; somewhat flared out or inflated and then narrowed at the opening
Campanulate--bell-shaped, with the segments gently flaring
Tubular--parts fused into a usually slender, uniform tube, usually with the free tips proportionately small and/or only slightly spreading
Funnelform--with parts fused into a tube that widens gradually from base to tip
Salverform-- with a narrow tube and an abruptly expanded, spreading portion which is often called the limb.  Here is another example.
Bilabiate--two-lipped (like a sock puppet); usually the perianth parts are fused at least below.  Here is another example.
Geniculate-- with an "elbow" or bend where the perianth changes direction suddenly
Papilionaceous--from the French word for "butterfly."  Applied to members of the Fabaceae in which the flower has one large petal, the banner or standard, two similar side petals called wings, and two folded or usually fused-together lower petals called the keel.  Here is a labeled image.
Spurred--with a spur-- a hollow, usually nectar-bearing, backward or downward extension of a sepal or petal.  A flower may have more than one. Spurs may be short as in Viola (spur is at the top of the flower, behind the pedicel)
Ligulate or Ray--zygomorphic and with all the petals pulled to one side into a flat, strap-like structure.  Typical of the sunflower family, e.g., the "petals" of a daisy

Cruciform--cross-shaped, with four petals arranged at right angles. 
Galeate--with a galea or hood.  Applies to flowers in which the upper lip is drawn forward, over, and often down.  Here is another example.
Gibbous--bulging or inflated (this example is only mildly gibbous, but you can see that the flower is expanded more on one side than the other)
Personate--with an arched upper lip and a lower lip that pushes up into the throat of the flower, forming a "palate"  (The flowers in the image are also spurred)
Fenestrate--(from the French for "window") with the parts fused into a tube and with a "window" or unfused opening in the side of the tube.  Typical of Lobelia.

NOTE:  That the above terms may be combined.  For example, a corolla may be both bilabiate and geniculate, or it could be tubular and spurred, etc.

Inflorescence Types

For each, the stalk of the inflorescence is called the peduncle and the stalk of an individual flower is the pedicel.

Fruit Types

Fruits can be categorized according to whether they are dry or fleshy and whether or not they dehisce (split open) at maturity

Placentation Types

Placentation refers to the pattern of attachment of ovules within the ovary.