Guide to Hornworts of Oregon: Phaeoceros hallii (Aust.) Prosk.

HOME         SPECIES INDEX        KEY


Hornworts 1b ventral tubers absent > Hornworts 2b spores yellow to brown > Phaeoceros 1b spores not brown > Phaeoceros 2b sporophytes less than 2cm > Phaeoceros 3a spores bumpy > P. hallii


Synonyms: Anthoceros hallii Aust.; Paraphymatoceros hallii (Aust.) Hässel de Menéndez

Special status: None

Recognition: Solitary chloroplasts in young epidermal cells characterize the family; yellow spores and a smooth thallus lacking stalked ventral tubers characterize the genus. This species has bright yellow spores that are ornamented (as seen under a light microscope) on their distal face with medium sized, coarse, round or crescentic, wart-like bumps (verrucae). Pseudoelaters are all one celled, unique in the genus; multicellular pseudoelaters are the norm. However, unicellular elaters may be found among two or more celled elaters in P. carolinianus (Doyle, pers. comm). The capsules are short for the the genus, usually less than 1 cm and distinctly curved. The only other species that is similar with short, curved horns is P. oreganus, whose capsules are up to 2 cm. The thallus of P. hallii often has rather dark, globose, tuberous thickenings at the apex and on marginal forks; tubers are lacking in P. oreganus.

Distribution: On wet soil, in wet prairies or next to seasonal seeps or springs. Not common, I have seen it from only four sites in Oregon. Specimens examined: Jackson Co.: Slagle Creek Wagner 9579 (DHW); Lane Co.: Coyote Prairie, Wagner m2691 (DHW); Fall Creek Reservoir, Wagner m0721 (DHW); Yamhill Co.: Deer Creek Park, S. Rose s.n. (DHW).

Comments: Hässel (2006) separated the genus Paraphymatoceros from Phaeoceros and Phymatoceros and included P. hallii in Paraphymatoceros. The segregate genus is based on having tubers which are different from those of Phymatoceros. However, Crandall-Stotler et al. (2008) have demonstrated clearly that P. hallii is closely related to P. pearsonii. These two form a complex within Phaeoceros that includes the recently described P. proskaueri from California (Crandall-Stotler et al. 2008).


Phaeoceros hallii. Coyote Prairie, Lane Co., Oregon. DHW field photo, April 2011.



Phaeoceros hallii. Left, very young sporophytes; right,thalli with marginal tubers. Coyote Prairie, Lane Co., Oregon. DHW m2720.



Phaeoceros hallii. Left, chloroplasts at 40X; right, chloroplasts at 100X. Coyote Prairie, Lane Co., Oregon. DHW m2720.



Phaeoceros hallii. Coyote Prairie, Lane Co., Oregon. DHW m2691.



Phaeoceros hallii. Coyote Prairie, Lane Co., Oregon. DHW m2691.



Elaters of Phaeoceros hallii. Coyote Prairie, Lane Co., Oregon. DHW m2691.



SEM spore images: distal, proximal, and side views. Calif., Madera Co., Oak Grove Rd., south of Mariposa. Doyle 8445 (UC); W.T. Doyle June 2007. Used with permission.



GO BACK ONE STEP


Copyright 2011 Northwest Botanical Institute