TEK - Identification of Phalaris species

[DarkDead]

It's now season to go hunting for Phalaris and although identifying a plant from this genus is rather easy distinguishing between species is not. This might be a problem as most are looking for the species reported to have a higher alkaloid content.
In the following paragraphs there will be concise information and accompanying images on how to differentiate Phalaris species. You can look online for more details on Wikipedia or on specialized botanical websites.

Grasses of the Phalaris genus can be easily detected even before they show flowers. They're usually taller than others and they have extended ligules.

Originally Posted by _caesar_

The only plant you could confuse it with is Phragmites. However, look for the ligule, Phalaris has an extended one but Phragmites has a ring of hairs instead.

240px-Rietgras_tongetje_Phalaris_arundinacea.jpg 270px-Riet_ligula_Phragmites_australis.jpg Font: Wikipedia and Trout
...... Phalaris ...... Phragmites .......
Please read the thread Detecting phalaris grass in nature? for more information.

Once plants show their panicles (flowering heads) this task becomes even easier and it's now possible to distinguish different species.

- Phalaris aquatica syn. Phalaris tuberosa is the tallest with up to 1,5 m, grows on wet lands and has a cylindrical dense flowering head with 3 to 10 cm. This flowering head has a reddish tone on some cultivars but that's not mandatory.
Phalaris_aquatica.jpg phalaris_aquatica_marin.jpg Font: Wikipedia and Trout

- Phalaris paradoxa might look like Phalaris aquatica however it's panicle is more oval and it usually grows on drier places. Underneath you'll learn how to make a precise distinction between these two.
phalaris_paradoxa_2.jpg phalaris_paradoxa_5.jpg Font: Luigi Rignanese

- Phalaris arundinacea is spoted quickly as it's flowers spread in branches unlike all the other species.
Rohrglanzgras.jpg phalaris_arundinacea.gif Font: king1sebastian and deoxy.org

- Phalaris brachystachys, canariensis and minor all grow on dry soils, are around 30-80 cm tall and have ovoid panicles. They're undistinguishable by the outer look and that's the reason why I wrote this thread. (When fully developed Phalaris minor panicles tend to be slenderer than those of the other 2, like shown in the photo below. However before that stage they look similar.)
0960.jpeg phalaris_canariensis_13.jpg phalaris0100.jpg Font: Luigi Rignanese, Schede di botanica and Forum Natura Italiana
brachystachys .. canariensis .. minor

You'll have to look closer on the panicles. If you put your fingers on these you'll be able to spread the little branches that constitute them. These are called spiklets and each has glumes attached. The glumes look like slender capsules, they're almost transparent but with green stripes. Inside the glumes are the florets (also called lemma) they're dark green and you can see flower parts coming out of them.
glumes_phalaris_lg.jpg Phalmin1.jpg Font: T. M. Jones and gemini.oscs.montana.edu

The distinction between Phalaris aquatica and Phalaris paradoxa can be made by the shape of their glumes:
phalar25.gif phalar40.gif Font: delta-intkey
aquatica ... paradoxa

Each glume has one main fertile floret (where the flower comes out of and that will later become a seed) and on it's base there might be small sterile florets. It's those sterile florets shape and number (per glume) that will allow you to distinguish between the three Phalaris species mentioned above.
glume and floret.jpg Font: gemini.oscs.montana.edu

- Phalaris brachystachys has 2 thin sterile florets that have at most 1/3 of the lenght of the main floret.
Phalaris brachystachys glume and floret 1.jpg Phalaris brachystachys glume and floret 2.jpg Phalaris brachystachys glume and floret 3.jpg Font: Ayahuasca: alkaloids, plants & analogs (Erowid) and ars-grin.gov

- Phalaris canariensis has also 2 sterile florets but these ones are thicker than those of brachystachys and reach 1/2 the lenght of the main floret.
Phalaris canariensis glume and floret 1.jpg Phalaris canariensis glume and floret 2.jpg Font: Ayahuasca: alkaloids, plants & analogs (Erowid) and ars-grin.gov

- Phalaris minor has only one really thin and short sterile floret. It's glumes are keel-winged and minutely toothed and the green stripes on them are broader than in the last two.
Phalaris minor glume and floret 1.jpg Phalaris minor glume and floret 2.jpg Phalaris minor glume and floret 3.jpg Font: Ayahuasca: alkaloids, plants & analogs (Erowid), ars-grin.gov and gemini.oscs.montana.edu

P.S. SWIM is collecting his own detailed photos of different phalaris species and their differentiating characteristics that I'll upload soon. Although my intention was to post this thread with them from the start the recent activity on phalaris threads made me decide to post this now.

Reputation Comments on this post:

	good tek, straight to the point
	Excellent concise guide, great effort.