Laboratory 9: Liliopsida, Subclasses VII andVIII

Alismatidae and Commelinidae

Objectives for this lab are to:
  • review the characters which distinguish monocots from dicots
  • know the characteristics of the subclasses Alismatidae and Commelinidae
  • learn key features of families and genera within the Alismatidae and Commelinidae
  • be able to identify structures in preserved, fresh, or mounted material of plants from these subclasses
  • identify subclass, family, and genus for selected members of these subclasses.
Safety concerns for this lab:  Use caution with dissecting tools, wear protective eyewear if working with specimens preserved in Carosafe, dispose of Carosafe specimens in proper waste container.  

Note: Family study exercises are designed to acquaint you with the major characters of some important flowering plant families. Follow the guidelines on your instruction sheets. Answer questions and diagram structures ON THE SHEETS and save them to study from. Diagrams, in addition to those requested in the lab instructions, will be useful. For exams, you will be expected to be able to identify structures present in preserved or fresh floral material. Herbarium specimens will be on display during each laboratory period. You should be able to identify these to genus, family, and subclass by recognizing the characters we discuss. For a copy of the overhead presented in lab, click here.


1. Sagittaria - Alismataceae -Alismatales:



 1. Tradescantia - Commelinaceae- Commelinales:

  2. Avena (Oat) - Poaceae (Gramineae) - Cyperales:

4. Carex - Cyperaceae - Cyperales:

5. Juncus (Rush) - Juncaceae - Juncales:

COMPLETE this lab exercise by making a comparison chart Concentrate on and list those features that consistently characterize each family. CONSIDER leaf arrangement, sheath features (open/ closed), stem shape (round/ angled), stem structure (solid/ hollow/ pithy), inflorescence structure, presence/absence/number of bracts, presence/absence of perianth, fruit type, etc. Make what drawings or notes you need to tell the families apart.

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last updated June 25, 2010 by MDR