West Highland Flora

One-rowed Watercress


Nasturtium microphyllum

 

Nasturtium microphyllum

Photo Carl Farmer
(16 Sep 2003 Musselburgh)

Occasional in ditches and wet ground

Flower diameter c 5-7 mm.  Ripe pods c 16-23 mm x 1.3-1.8 mm on stalks 14-19 mm (Stace)

ID: Use pod measurements above (ripe pods only, average several).  Alternatively, split open pods.  Seeds are in one row in each of the two pod cells, not in two overlapping rows as in Two-rowed Watercress.  The seeds may not be in an exact straight line but in a single wavy line, with possibly one or two opposite pairs at the base.  Watercresses are told from other crucifers with fully pinnate leaves, white flowers and linear pods by complete absence of hairs on leaves or stems.

Other features: Leaves turn purple-brown in autumn, see pic below.  The two Watercresses hybridise quite often.  The hybrid is easy to recognise as it does not produce proper pods but small and distorted ones with few or no seeds.

 

Nasturtium microphyllum

Photo Carl Farmer
(14 Sep 2003 Longniddry, E Lothian)

 

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