Echinochloa crus-galli -ryhmä

When you come across a barnyard grass in bloom in Finland, you can immediately tell that this is an exotic grass. None of the permanent grass families in this country have a similar branching compound spike, in which the spikelets are located in one or several rows on quadrangular, sturdy branches. Even the minor features of the spikelets are unique, for example: a hemispherical outer and flat inner surface, the lower flower being sterile (no stamens nor pistils) and the upper hermaphroditic, the lemma of the upper flower is hemispherical, cartilaginous, glossy and pale. The lemma of the lower flower is often awned, but the same compound spike often has both awn-pointed spikelets and ones without, and the length of the awns may vary greatly from one spikelet to another, making the inflorescence appear somewhat untidy. On the other hand, there are forms whose compound spike resembles a neat collection of pipe-cleaners or a brush, as almost all of the spikelets have short or long awns. The colour of the inflorescence also varies, partly in accordance with the degree of light in the habitat, ranging from dull light green via partly reddish to completely dark reddish brown. Barnyard grasses without inflorescence can be identified based on features such as their fairly flat, often purplish base and the glabrous, rough-edged, non-ligulate leaves, but this requires experience that can be gained by examining the vegetative parts of flowering individuals.

In Finland, the barnyard grass species Echinochloa crus-galli, the actual barnyard grass, and rough barnyard grass (E. muricata) are important in this context. They should be reviewed at group level when checking for alien species, for three reasons: (1) in Finland, they were not considered separate species until the 2000s, (2) not everyone is able to tell them apart; indeed, this is not possible unless the individuals are flowering, and (3) their requirements, and habitats and control methods, are similar (however, see the statement on herbicides below). In practice, barnyard grasses must or can be discussed collectively. This species card ‘Echinocloa’, barnyard grasses, therefore covers both species and all observations should be reported using the card, unless the species is identified with absolute certainty.