Vascular Plants of the Gila Wilderness

Presented in Association with the
Western New Mexico University Department of Natural Sciences

Marrubium vulgare Linnaeus
(Horehound)


Family: Lamiaceae

Status: Exotic

Synonyms:
None

Marrubium vulgare is a pest. It grows anywhere and everywhere it can get started at lower to middle elevations, frequently in the shade of trees in a ring around the trunk but also in sidewalks and waste areas. The wrinkled, grayish leaves and nearly hidden white flowers are easy to recognize. The ten spreading and hooked calyceal teeth act like velcro and are dangerous to pets as they can work themselves deeply into fur. The flowers have 4 stamens that are adnate (fused to) the corolla-- epipetalous stamens. The lower corolla lobe is made up of 3 fused petals and the upper lobe is made up of 2 fused petals. There are a total of 4 stamens- 2 long and 2 short ones, a morphology known as didynamous stamens. The style is divided into two unequal lobes.
Please click on an image for a larger file.



Marrubium vulgare, photo Russ Kleinman, Silver City, May 19, 2007



Marrubium vulgare, closeup of flowers, photo Russ Kleinman, Silver City, April 30, 2009



Marrubium vulgare, macro of calyx and four black nutlets, photo Russ Kleinman, Pinos Altos Range, Pinos Altos, December 2, 2009



Marrubium vulgare, macro of group of calyces each with 10 hooked teeth to stick in fur, photo Russ Kleinman, Pinos Altos Range, Pinos Altos, December 2, 2009



Marrubium vulgare, macro of stem cross sections, photo Russ Kleinman, Pinos Altos Range, Pinos Altos, July 16, 2011



Marrubium vulgare, floral dissection, photo Russ Kleinman, Pinos Altos Range, Pinos Altos, November 8, 2022



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