A perennial species, up to 50 cm tall, with stems provided with very sharp opposite leaves and elongated sheath. The red or pink flowers are located in dense clusters on an involucre of bracts of leathery texture. The gamosepalous and ribbed calyx is reddish at the end and is surrounded halfway by the calyx pieces, which have rigid and divergent tips. It flowers from June to September in soils with low humidity.