BFNA Title: Amphidium
Author: D. H. Vitt  
Date: October 6, 2003
Edit Level: R Brum+
Version: 1

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden
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Amphidium  - Orthotrichaceae


1.  Amphidium Schimper, Coroll. Bryol. Eur. 39.  1856 * [a variant of Amphoridium (nomenclaturally unavailable) and means like an urn, referring to the capsule shape].

Dale H. Vitt

Plants small, in dense cushions.  Stem leaves twisted and contorted when dry, linear to narrowly lanceolate, acute; margins entire or toothed above, costa strong; distal laminal cells small, rounded, obscured by numerous, elliptic cuticular papillae over lumens and transverse walls; basal cells yellow-clear, smooth. Sexual condition autoicous or dioicous.  Perichaetial leaves larger and ± clasping seta; gemmae not produced. Seta short 1.0--3.5 mm.  Capsule oblong, 8-ribbed, constricted below mouth, mostly emergent to immersed; peristome none; stomates superficial.  Calyptra cucullate, naked, smooth.  Spores isomorphic.


Species 12 (3 species in the flora); North America, Europe, Asia, Africa, Pacific Islands, Australia.


Limey green cushion-forming plants in seepages of non-calcareous rocks is descriptive and diagnostic for all species.  The lack of a peristome has lead to considerable discussion of the placement of the genus.  J. Lewinsky (1976) suggested correct placement in the Orthotrichaceae while D. H. Vitt (1973) proposed the Rhabdoweisiaceae.  Although treated here in the former family, recent DNA evidence indicates closer relationships with the Haplolepideae (Goffinet et al. 1998) and the latter family (Stech 1999).


1.  Leaves toothed or notched above . . 1. Amphidium californicum

1.  Leaves entire.

2.  Autoicous; leaves ligulate-lanceolate; distal laminal cells 8--11 µm, obscured by relatively large, warty cuticular papillae; operculum short-rostrate, less than diameter of capsule; capsules immersed to half emergent . . 2. Amphidium lapponicum

2.  Dioicous; leaves linear; distal laminal cells 5--9 µm, somewhat obscured by numerous, small, elliptic cuticular papillae; operculum rostrate, greater than diameter of capsule); capsules barely exserted. . . . 3. Amphidium mougeotii


SELECTED REFERENCE   Goffinet, B., R. J. Bayer, and D. H. Vitt. 1998.  Circumscription and phylogeny of the Orthotrichales (Bryopsida) inferred from rbcL sequence analyses.  Amer. J. Bot. 85: 1324--1337.   Stech, M. 1999.  A molecular systematic contribution to the position of Amphidium Schimp. (Rhabdoweisiaceae, Bryopsida).  Nova Hedwigia 68: 291--300.


1. Amphidium californicum (J. K. A. Müller) Brotherus, Nat. Pfl. 1(3): 460.  1902 


Zygodon californicus J. K. A. Müller, Bot. Zeit. 20: 361.  1862


Plants 1--4 cm.  Stem leaves 1.5--4 mm, linear-lanceolate; margins toothed to notched distally, toothed or entire proximally, recurved; basal laminal cells thick-walled, yellowish; distal laminal cells 9--11 µm wide, lightly obscured by numerous tiny elliptic cuticular papillae, these often in longitudinal lines.  Sexual condition dioicous.  Perichaetial leaves subsheathing at base, elongate, narrow, long-pointed.  Seta 1.5--2 mm.  Capsule immersed to emergent, 1.2--1.6 mm.  Operculum conic-apiculate.  Spores 10--15 µm.


Crevices of neutral to acidic rocks; mostly at middle elevations; B.C.; Calif., Idaho, Oreg., Wash.


The leaves with notched distal leaf margins and linear leaves distinguish this species.  Amphidium lapponicum has decidedly broader leaves and distal cells obscured by large, warty, cuticular papillae.


2. Amphidium lapponicum (Hedwig) Schimper, Coroll. Bryol. Eur. 39.  1856 


Anictangium lapponicum Hedwig, Spec. Musc. 40.  1801


Plants 0.5--3.5 cm.  Stem leaves 2--3 mm, ligulate-lanceolate; margins entire, plane; basal laminal cells firm-walled, clear; distal laminal cells 8--11 µm wide, obscure, densely warty-papillose.  Sexual condition autoicous.  Perichaetial leaves sheathing, enlarged, erect, short-pointed.  Seta 1--1.5 mm.  Capsule immersed to half emergent, 0.8--1.3 mm.  Operculum short-rostrate.  Spores 9--13 µm.


Seasonal wet crevices of neutral to acidic cliffs; 100--2000 m; Greenland; Alta, B.C., N.B., Nfld., N.W.T., N.S., Nun., Ont., Que., Sask., Yukon; Ala, Ariz., Calif., Colo., Conn., Idaho, Maine, Md., Mich., Minn., Mont., Nev., N.H., N.J., N.Y., Oreg., Pa., Vt., Va., Wash., Wis., Wyo.; Europe; Asia.


Amphidium lapponicum differs from the two other North American species by broader leaves and larger, warty, cuticular papillae that obscure the distal leaf cells.  It is autoicous and frequently fruiting, in which case the immersed to emergent capsules serve to identify it.  Additionally, the larger leaf cells (8--11 µm) differentiate this species from the other entire-margined species, A. mougeotii, which has distal leaf cells smaller (5--9 µm).


3.  Amphidium mougeotii (Bruch, Schimper, & W. Gümbel) Schimper, Coroll. Bryol. Eur. 40.  1856


Zygodon mougeotii Bruch, Schimper & Gümbel, Bryol. Eur. 3: 39. 206. 1836


Plants 2--5 cm.  Stem leaves 1.5--3 mm, linear-lanceolate; margins entire, plane; basal laminal cells thick-walled, yellowish; distal laminal cells 5--9 µm wide, opaque, lightly obscured by numerous tiny elliptic cuticular papillae. Sexual condition dioicous.  Perichaetial leaves subsheathing at base, elongate, narrow, long-pointed.  Seta 2.2--3.5 mm.  Capsule barely exserted, 1--1.5 mm.  Operculum rostrate.  Spores 9--12 µm.


Seasonally wet crevices of neutral to acidic cliffs; 10--1500 m; Greenland; B.C., N.B., Nfld., N.W.T., N.S., Nun., Ont., Que., Yukon; Ala., Alaska, Calif., Colo., Conn., Ga., Idaho, Ky., Maine, Minn., Mont., N.H., N.Y., N.C., Ohio, Oreg., Pa., S.Dak., Tenn., Vt., Va., Wash., W.Va.; Europe; Asia.


This species has linear, entire leaves and small leaf cells (5--9 µm).  The cuticular papillae are numerous, elliptic, and only lightly obscure the distal cells, whereas in A. lapponicum they are larger, warty, and much more noticeable.