BFNA Title: Daltoniaceae
Author: P. M. Eckel
Date: May 11, 2011
Edit Level: R
Version: 2

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden
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Patricia M. Eckel


Plants small to medium, in dark green to yellow-green turfs or mats. Stems short, not or sparingly branched, with crowded leaves spirally inserted; often red, in section with moderately differentiated cells; cortex deeply red pigmented, inner cortical cells somewhat larger than the outer, the walls thinner; outer cortical cell walls somewhat smaller and thicker; rhizoids from stem bases, sometimes clustered proximal to leaf bases, sparingly branched (not 2--3-pinnate); central strand usually lacking; pseudoparaphyllia absent [rarely filamentous]; axillary hairs with hyaline cells 3-4(--12), basal cell usually small and brown. Leaves terete-foliate [complanate], often dorsiventrally differentiated and asymmetric; margins bordered [rarely not bordered], entire to serrate or ciliate  cells short, usually rounded, isodiametric [oval] to (long-) hexagonal, mostly with firm walls, smooth, not differentiated in the basal region; costa usually single, stout. Sexual condition: autoicous, dioicous or synoicous. Specialized asexual reproduction various, common. Seta lateral, usually elongate, smooth, often roughened to spinose. Capsule erect or inclined, annulus absent [present]; peristome double, exostome of 16 teeth, thin, papillose, not bordered or furrowed, [outer plates thick, furrowed, cross-striolate], endostome with low basal membrane, segments papillose; cilia reduced or absent; operculum erect, subulate, beaked. Calyptra mitrate, base with [without] fringe of 1-celled hairs [multicellular], 1-stratose at the middle, usually naked, rarely densely hairy.


Genera 14, species ca. 150 (1 genus, 1 species in the flora): mainly tropical and hyperoceanic southern-temperate.


Most of the genera in the Daltoniaceae are complanate leaved (W. Frey 2009), and it is conspicuous that the only genus in the flora area, Daltonia, one of the three largest genera in the family, has leaves that are spirally inserted and terete-foliate. Daltonia is one of the few genera in the family to display a synoicous sexual condition, in addition to autoicous but not dioicous species. Only Distichophyllum, usually dioicous or autoicous, is rarely synoicous (W. Frey 2009). The leaf shape is also distinctive in the family. Leaves of many Daltonia species are lanceolate with nearly parallel sides, gradually acuminate, quite distinct from the ovate or obovate, abruptly apiculate or obtuse leaves common in other genera and species in the family. Daltonia shares the epiphyllous character of the family.


SELECTED REFERENCES   Frey, W., ed. 2009. Syllabus of Plant Families: A. Engler's Syllabus der Pflanzenfamilien. Part 3. Bryophytes and seedless Vascular Plants. Berlin. Goffinet, B., W. R. Buck, and A. J. Shaw. 2008. Morphology, Anatomy, and Classification of the Bryophyta. In: B. Goffinet and A. J. Shaw, eds. Bryophyte Biology, ed. 2. Cambridge.


1. DALTONIA  Hooker & Taylor, Muscol. Brit. 80. 1818, name conserved * [For Rev. John Dalton, British botanist and bryologist, 1764--1843]


Plants glossy, dark to yellow-green to brownish. Stems prostrate or suberect with short, ascending branches, to 1 cm. Leaves erect or erect-spreading, flexuose when wet, flexuose-twisted and contorted when dry, ovate-lanceolate, ligulate- to lance-acuminate, 1--3 mm, keeled, all similar, symmetric, straight, not dorsiventrally differentiated, laminal cells generally incrassate, generally uniform in shape, rhomboidal to elongate-hexagonal, sometimes rounded, smooth, longer near the base; margins strongly bordered with several rows of incrassate, linear cells, entire, plane or recurved, sometimes variable on same stem; costa ending before the apex in the distal quarter. Specialized asexual reproduction by multicellular gemmae, variously shaped. Sexual condition autoicous or synoicous. Seta scabrous distally [smooth]. Capsule erect; annulus absent; exothecial cells strongly collenchymatous; peristome teeth without striations, densely papillose, with zig-zag longitudinal lines, hygrocastique (teeth incurved when dry and reflexed when moist), not furrowed; segments same length as teeth, narrow, perforate along keels, linear, densely papillose. Calyptra smooth to somewhat roughened distally, with dense basal fringe hairs. Spores papillose.


Species ca. 22 (1 in the flora):  nw North America, South America, Europe, Asia, Africa, Indian Ocean Islands (Reunion), Pacific Islands (New Zealand), Australia.


1. Daltonia splachnoides (Smith) Hooker & Taylor, Muscol. Brit., 80. 1818  C F


Neckera splachnoides Smith, Engl. Bot. 36: 2564. 1813; Daltonia gracilis Mitten


Stems to 10(--15) mm, often deep red. Leaves 1--3 mm, to 0.4 mm wide; margins plane or variably revolute on leaves from the same stem (throughout one side, partially distally or proximally); entire, carinate as a narrow median fold; margin border distinct to the insertion, well defined in 6--8 rows at the base,  3--4 rows at midleaf and reduced to ca. 2 rows in the acumen; distal cells ovate to rhomboidal to narrowly rhomboid-hexagonal, 12(--24) x (6--)7 \um,  incrassate, pellucid basal cells linear-oblong, to 50 \um, hyaline, stem cortical cells attached at the leaf insertion. Seta 6--7 mm, red to red-brown, papillose-scabrous in distal 1/2. Capsule red-brown to dark brown, erect to subinclined, obovoid with a short neck, papillose; exothecial cells collenchymatous, papillose; operculum rostrate. Calyptra slightly roughened distally. Spores ca. (10--)14--16 \um.


Capsules mature summer. Base of trees, fallen branches, trunks of shrubs and trees, forests, foggy, hyperoceanic areas, 0--300 m; B.C. (Queen Charlotte Islands); California (San Francisco Co.); Mexico; West Indies; Central America; South America; Europe (Ireland); Asia (China); Atlantic Islands; Pacific Islands (New Zealand); Australia.



In the flora area Daltonia splachnoides is known only from San Francisco Co., California, Eucalyptus and Cupressus forest, in partial shade on fallen branches of Cupressus or trunks of Myoporum laetum or bases of Eucalyptus, and the Queen Charlotte Islands, British Columbia, being first collected by W. B. Schofield on Moresby Island (W. H. Welch 1972). Commonly, D. splachnoides is distinguished by plane laminal margins. In the Moss Flora of Mexico (F. D. Bowers 1994), the five Daltonia species reported from that country fall into two groups: one with the leaf margins plane throughout or occasionally reflexed proximally and the other with leaf margins narrowly revolute. For D. gracilis, the margins are described as “narrowly revolute nearly throughout or only here and there and on 1 side or the other, or both.” In the introduction to E. B. Bartram's (1931) review of the genus, he repudiated reports of D. splachnoides from Mexico and the Antilles, although admitting the closeness of that species to D. gracilis. He reiterated the rejection of D. splachnoides from American stations again under his treatment of D. longifolia. Examination of specimens from Ireland and Australia reveal to the present author that variation in leaf marginal recurvature of D. splachnoides is the same as that described for D. gracilis in Mexico. In a paper by J. Yu et al. (2010), the two species are treated as synonymous since all South American exemplars are given as D. splachnoides, none as D. gracilis. Given that D. spachnoides exemplars group well worldwide, molecular analysis supports the synonymy of the two species as does the morphological similarity observed. In press is a revision of the American species of Daltonia by Piers Majestyk (personal communication), who provided the above estimate of the actual number of species and information on asexual reproduction..





Bartram, E. B. 1931. A review of the American species of Daltonia. Bull. Torrey Bot. Club 58: 31--48.


Dixon, H. N. 1924. The Student's Handbook of British Mosses, ed. 3. London.


Smith, A. J. E. 2004. The Moss Flora of Britain and Ireland, ed. 2. Cambridge.


Yu, J., N. Devos, P. Majestyk and A. J. Shaw. 2010. Intercontinentally disjunct species are derived rather than relictual in the moss genus Daltonia (Bryophyta). Taxon 59: 459--465.


Welch, W. H. 1972. Hookeriaceae: North America and West Indies, Additions and Appendix. Bryologist 75: 456--461.