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Rorippa islandica

Marsh Cress · Northern Yellow-cress · Yellow Watercress · Northern Marsh Yellowcress

Family BrassicaceaeGenus Rorippa

A sprawling plant of deeply lobed leaves on reddish stems, with small yellow flowers and slim green seed pods, over wet gravel and moss.
The whole plantRagnhild&Neil Crawford from SwedenCC BY-SA 2.0

About the plant

What it is and where it grows — not part of any germination protocol.

Habit
annualPlants of the World Online
Habit
Annual, Biennial, Forb/herbPLANTS Database
Native range
Altay, Austria, East European Russia, France, Germany, Great Britain and elsewhereGBIF Backbone Taxonomy

Toxicity is noted only where a source states it. No note here is not a finding of safety.

Sources: Plants of the World Online — Royal Botanic Gardens, Kew; PLANTS Database — USDA NRCS; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.

This source reports three treatments. All are shown.

Protocol 1

DerivedN. C. Deno, 1996

Difficulty Low Rated by us, not by the source.

Start around March 8, 2027 for a May 3 last frost.

  1. Sow and cover

    Temperature: 70°F 21°C Light: light

No stated waiting before sowing. Then 28 days to germinate.

90% germination in 28 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Rorippa p. 71Public domain
Show the original text
Rorippa (Brassicaceae). R. islandica germ. 70L(90% in 4th w), 70 GA-3(80% in 3rd w), and none in 70D or 40. DS at 70 for 3 m had no effect, but DS for 1 y lowered germination in 70L to 8%.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Rorippa p. 71. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 2

DerivedN. C. Deno, 1996

Difficulty Low Rated by us, not by the source.

Start around March 15, 2027 for a May 3 last frost.

  1. Gibberellic acid soak

  2. Sow and cover

    Temperature: 70°F 21°C

No stated waiting before sowing. Then 21 days to germinate.

80% germination in 21 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Rorippa p. 71Public domain
Show the original text
Rorippa (Brassicaceae). R. islandica germ. 70L(90% in 4th w), 70 GA-3(80% in 3rd w), and none in 70D or 40. DS at 70 for 3 m had no effect, but DS for 1 y lowered germination in 70L to 8%.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Rorippa p. 71. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 3

DerivedN. C. Deno, 1996

  1. Sow and cover

    Temperature: 70°F 21°C Light: dark

No stated waiting before sowing.

0% germination.

Nothing germinated at 70.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Rorippa p. 71Public domain
Show the original text
Rorippa (Brassicaceae). R. islandica germ. 70L(90% in 4th w), 70 GA-3(80% in 3rd w), and none in 70D or 40. DS at 70 for 3 m had no effect, but DS for 1 y lowered germination in 70L to 8%.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Rorippa p. 71. Quoted exactly. Every value on this card comes from this record; the step names come from a fixed list.

How each step is done, in Deno’s words, and what Verified and Derived mean.

Germination trials

Readers’ own records of sowing this species, published after review. Share your trial · All trials

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