Sahara Mustard Consortium

... a UC resource for managing Sahara Mustard, Brassica tournefortii
 
Identification
Pictures

This is a pictorial key that is designed to help you determine if the plant you see or have (collecting a sample is recommended) is Sahara mustard.

It is not perfect, hopefully I have provided enough features to get you to the correct identity. You will need more than one character to get a proper ID, how steps many depends on the sample you took.

IMPORTANT: If your sample does not match, especially the fruit characteristics, its likely not Sahara mustard. (Characters 5 and 6 are especially helpful.)

If you are in the desert and see a large field of mustard plants they are likely Sahara mustard. You will not need all of these steps for a proper identification, but I’ve included many of them to help you be correct in your ID.


The Sahara mustard Consortium is brought to you by Chris McDonald, Natural Resource Advisor with the University of California, Cooperative Extension.


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The cotyledon (seedling leaves) of Sahara mustard has the characteristic shape of many plants in the mustard family, it has two round lobes (or a dip out of the top). Similar to a radish or broccoli seedling.


This will tell you your unknown seedling is likely in the mustard family.

Sahara mustard on Left, sand verbena (native) on right


The growth of young plants forms a basal rosette (a circle of leaves along the ground). As the leaves get older they have 4-12 pairs of lobes on the sides with a white vein running down the middle.


These characters will tell you your unknown plant is in a small part of the mustard family.

Sahara mustard tends to have prickly hairs on the leaves with a raised base (see the tiny white dots), also look at the hairs on picture #1. The native sun cup is the smaller brown plant growing under the Sahara mustard.


Thee characters will tell you your unknown plant is in a small part of the mustard family.

Sahara mustard flowers are yellow and have 4 petals, forming a cross or “X”, they are about the size of a fingertip (1cm, 0.5in). The flower has 6 anthers (the male part of the flower that produces pollen). Look very closely at your sample (you might need a magnifying glass) and 2 of the anthers will be lower and the other 4 will be taller. You can barely see it in this picture (the anthers on the far left and far right are shorter).


Thee characters will tell you your unknown plant is in the Brassica genus.

1

2

3

4

The pedicel (stalk that holds the fruit) of Sahara mustard is at a 45-60 degree angle from the flowering stem (inflorescence). The pedicel is NOT pressed against the flowering stem


This character differentiates Sahara mustard from a few other mustards.

5

Sahara mustard has a long “beak.” A structure at the end of the fruit that contains 1 seed. It looks similar to the beak of a hummingbird. There is one seed in the beak pictured above. NOTE: the beak pictured above is unusual in that it is darker than the rest of the fruit, the beak is usually light brown, (but it works great for this picture to highlight the beak)


This character differentiates Sahara mustard from most other mustards

6

The fruit of Sahara mustard has two chambers, note the red seed on top of the thin membrane separating the chambers. Technically the fruit of a mustard is a silique. The silique of Sahara mustard has two chambers separated by a thin, light brown and translucent membrane. The fruit is about 5 cm long. FYI There is no membrane in a green bean and a green bean fruit is a pod.


This character likely places the unknown fruit in the mustard family

7

The seeds of Sahara mustard are greater than 1mm round (this is larger than 1/32 inch but smaller than 1/16 inch). The seeds are also a brick red color, fading to blackish red as they age. Sahara mustard seeds tend to be larger than other mustards, especially other common mustards.


This character differentiates Sahara mustard from some other mustards.

8

Image courtesy of USDA-ARS. Steve Hurst. Provided by ARS Systematic Botany and Mycology Laboratory. Spain.

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