Mystery Seed of the Week 197: Challenge 6

As a run up to our 200th Mystery Seed, we are doing few new challenges as a contest.  The idea of the challenges will be to introduce some real world reasons why someone might need to identify seeds. Prizes will be awarded in post 200.

Challenge 6.

Scenario:  You work for the Department of Agriculture in Australia. It is your job to keep invasive weeds out of the country.

A shipment of seeds arrives with some round black seeds mixed in.


A. What kind of seeds are they?


B. Should the shipment be rejected or not? To help with your decision, see the lists of Australian invasive weeds at Weeds of National Significance. (Google is okay for this, as well.)

Edit:  For this week’s challenge, you only need the genus and/or common name of the plant because the species names are somewhat in flux. A. 5 points for the first correct identification, 1 point for each subsequent correct answer. B. 5 points for the first correct response indicating whether the plant is invasive in Australia, 1 point for each subsequent correct answer.

Challenge 6 is now closed. The answer is posted in challenge 8.

Only 2 more challenges to go.


Answer to challenge 4:

The brown, rounded seeds were indeed radish seeds, Raphanus sativus, and the oval, spiky seeds were carrots, Daucus carota subsp. sativus.

By the way, this seed mixture works well when planted together as the radishes germinate and grow quickly, whereas the carrots are much slower. Pulling out the radishes allows the carrots plenty of room to develop roots.

Challenge 4 is now closed. Thank you to everyone who participated.

The answers to challenge 5 will be revealed next week.

New mystery seeds and Seed of the Week answers are posted on Tuesdays.


  1. Anna

    I think this is prickly pear cactus. (Sorry if this is a repeat comment. I’m having trouble with buttons this morning. Please delete if so, thanks).

  2. Craig

    Is the image of the seed itself or is it a fruit (ie is the black part able to be peeled off to reveal the seed?)

  3. Roberta

    The seed comes in a round red fruit that I peeled away to reveal this.

    Anna, because you already answered without this information, you may enter a second answer if you’d like.

  4. Craig

    Asparagus sp.

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