Gentian affinis / pleated gentian

Adjectives: clonal, fen, native, wet meadows

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The pleated gentian is a brilliantly blue (mostly) flower that stands out even though the plants are crowded in with everything else in a fen, in moist or boggy soils along road sides or in wet meadows. You may even see it in lightly-covered woodlands if they are wet enough. It’s often found in dense clusters of a dozen or more plants, with clusters scattered widely in, for example, wet meadows or fens. Part of this clustering is due to growth of multiple stems from a common base (branched caudex).

Once you see the flowers, the next step, of course, is to establish that this is the pleated gentian and not something else. First, the color… although blue is what you will probably see, purple-ish is also possible. The inflorescence may be a single flower, or a small group at the top of a stem. Flowers arising at the very top are stemless; those arising from leaf axis below that are on short pedicels. The technical term for the inflorescence is a “leafy-bracteate” panicle, i.e. a panicle with leafy bracts.

The flowers are only about 1 – 1.5 inches long. They are erect and funnel shaped (like other Gentian spp). Each flower has 5 fused petals to make the funnel and the lobes have pointed tips, rounded edges and are more or less triangular in appearance. Most diagnostic, however, is the connective tissue between the lobes, being pleated (hence the common name) and ragged at the outer edge. The petals/lobes are covered with whitish/greenish little spots (a distinctive feature) while the surfaces of the funnel tube may be lined with whitish/greenish streaks.

The leaves of pleated gentian, if you can find them amongst all the competing foliage, are simple and opposite, without petioles, teeth, or hairs (at least mostly). They are lance-shaped, i.e. at least 3 times longer than broad. Each set of leaf pairs is at right angles to those above and below, reflecting the fact that the stems are square in cross section. The leaves are what you can use to easily distinguish this from explorer’s gentian.

As with many other flowers on this site, the other key feature is variability. Sometimes, the stems may be reddish, other times green. The flowers may be open or remain closed. The clusters may be large or small. There may be clumps of flowering stems or single shoots.

It is especially refreshing to see this little flower late in the summer or into the autumn when everything else in bloom seems to be an aster of some sort.