141. The burdock

The lesson, step by step

1. When and where

   Burdock grows in waste places, barnyards and roadsides. It flowers in mid to late summer; the brown burs stay on the dead plant through winter. Burs tangle in hair and pets' fur, so keep dogs back.

2. The leading thought

   The burdock wins because its great leaves shade down plants in its vicinity, and also by having taproots. It scatters its seed by hooking its seed-heads fast to the passer-by.

3. The shady leaves

   Note a young plant. How much space does its leaves cover? Is anything growing beneath them?

   Measure across the biggest leaf with the tape. Lift it and look underneath.

4. Leaves that don't shade each other

   Study the arrangement of leaves on a burdock plant, to discover how it manages to shade down other plants with its leaves and yet does not let its own upper leaves shade those below.

5. Flowers and burs

   Where do the flowers appear on the stem? Are there many flowers developed? Count all the flower-heads on a thrifty burdock.

   What insects visit the burdock flowers? Can you make baskets from the flower-heads?

   With gloves on, press burs together; they hook to each other and make little baskets.

6. Hitch-hikers

   How are the seed-heads carried far away from the parent plant?

   Look at a bur with the lens: every bract ends in a tiny hook. A Swiss engineer got the idea for hook-and-loop fasteners (Velcro) from burs like these stuck to his dog.

7. Nature notebook

   Draw one bur, enlarged, with its hooks. Then, for a writing day, Comstock's question:

   Write the biography of a burdock plant which came to America as a seed, attached to the tail of a Shetland pony.