Lachnagrostis filiformis (G. Forst.) Trin. (syn.: L. avenacea (J.F. Gmel.) Veldkamp, Agrostis avenacea J.F. Gmel.) (Austr., Polynesia, New Zealand) – A very rare and ephemeral alien. Formerly (at least between 1892 and 1967) more or less regularly seen as a wool alien in the valley of river Vesdre in the surroundings of Verviers. In 2013 a single plant was recorded near a grain mill in the Roeselare port area. Australian cereals being rarely imported in Belgium (if ever), this specimen probably originated from a secondary area where the species in naturalized, for instance from the Americas or South Africa.
In general appearance Lachnagrostis filiformis is much reminiscent of Agrostis scabra and both might have been intermixed. Both are caespitose annuals or short-lived perennials with a very diffuse, often detaching inflorescence with numerous tiny spikelets. However, Lachnagrostis filiformis has lemmas that are always awned and densely pubescent, paleas are well-developed (usually at least 2/3 as long as lemma) and leaf blades seem to be flat and slightly wider. In Agrostis scabra plants with awned and unawned lemmas occur (although only the latter have been recorded so far in Belgium) and these are always glabrous. Paleas are absent or minute and leaves are often nearly filiform and involute.
 |
|
 |
 |
Selected literature:
Nava Rojo A., Gómez-Sánchez M. & González Ledesma M. (2002) Agrostis avenacea (Poaceae: Pooideae): first record for the Mexican flora. Sida, Contrib. Bot. 20(1): 423-429. [available online at: https://archive.org/details/cbarchive_38556_agrostisavenaceapoaceaepooidea2002]
Portal R. (2009) Agrostis de France. Vals près Le Puy: 303 p.
Sanchez-Ken J.G. (2018) Lachnagrostis filiformis (Poaceae: Pooideae: Poeae: Agrostidinae) in México: known distribution and suppression of lemma awn development in terminal spikelets. Phytotaxa 350(3): 223–234.
Smook L. & Stirton C. (1979) Notes on African plants: Poaceae. Naturalized Agrostis in South Africa: Agrostis avenacea and A. montevidensis. Bothalia 12(4): 637.