rediScovery of Timmiella acaulon (Timmiellaceae) in  
The chaco Province, norTheaSTern argenTina  
redeScubrimienTo de Timmiella acaulon (Timmiellaceae) en la  
Provincia de chaco, noreSTe de argenTina  
1
2
3
Soledad Jimenez * , Richard H. Zander & David Iriart  
Summary  
Backgroundandaims:Herbarium specimens were reviewed as part of broader project  
that deals with the diversity of bryophytes from the Chaco province (Argentina).  
One of the samples matched the description of Timmiella acaulon, a species poorly  
known. The aim of this work is to record T. acaulon as new to Chaco Province and  
to describe morphologically and illustrate in detail this remarkable species.  
M&M: Herbarium samples were analyzed with standard techniques for bryophytes.  
Examination with scanning electron microscope was made using samples mounted  
directly on double-sided tape and coated in gold-palladium.  
1
. Instituto de Botánica del  
Nordeste (IBONE, CONICET-UNNE),  
Corrientes, Argentina  
2
. Missouri Botanical Garden, St.  
Louis, Missouri, United States  
. Laboratorio de Ecología (FaCENA,  
UNNE), Corrientes, Argentina  
3
Results: Timmiella acaulon is newly registered for Chaco province. A complete and  
detailed morphological description, and illustrations are here presented.  
*msoledadjimenez@exa.unne.edu.ar  
Conclusions: Due to the rediscovery of the species more than 100 years after its  
original description, the distribution range of T. acaulon is extended to northeastern  
Argentina, and details of morphological characters of systematic value are provided.  
Citar este artículo  
, R. H. ZANDER & D.  
IRIART  
JIMENEZ, S  
2023. Rediscovery of  
.
.
Timmiella acaulon (Timmiellaceae)  
in the Chaco Province, northeastern  
Argentina. Bol. Soc. Argent. Bot. 58:  
Kew wordS  
Haplolepidous, Timmiellaceae, Timmielloideae, Trichostomum.  
521-527.  
reSumen  
DOI: https://doi.  
org/10.31055/1851.2372.v58.  
n4.41102  
Introducción y objetivo: Se revisaron especímenes de herbario como parte de un  
proyecto más amplio que trata sobre la diversidad de briófitas de la provincia del  
Chaco (Argentina). Un ejemplar coincidió en su descripción con Timmiella acaulon,  
una especie escasamente conocida. El objetivo de este trabajo es registrar a T.  
acaulon como nueva para el Chaco, y describir morfológicamente e ilustrar en  
detalle esta singular especie.  
M&M: Los ejemplares de herbario se analizaron según técnicas tradicionales para  
briófitas. Los análisis en microscopio electrónico de barrido se realizaron con  
muestras montadas directamente en cinta doble faz y recubiertas de oro-paladio.  
Resultados: Timmiella acaulon se registra por primera vez para la provincia del  
Chaco. Se presenta una descripción morfológica detallada e ilustraciones.  
Conclusiones: Debido al redescubrimiento de la especie después de más de  
100 años de su descripción original, la distribución de T. acaulon se amplía al  
noreste argentino, y se proporcionan detalles de caracteres morfológicos de valor  
sistemático.  
PalabraS claveS  
Haplolépido, Timmiellaceae, Timmielloideae, Trichostomum.  
Recibido: 4 May 2023  
Aceptado: 2 Oct 2023  
Publicado en línea: 30 Nov 2023  
Publicado impreso: 22 Dic 2023  
Editor: Guillermo Suárez  
ISSN versión impresa 0373-580X  
ISSN versión on-line 1851-2372  
521  
Bol. Soc. Argent. Bot. 58 (4) 2023  
inTroducTion  
maTerial and meThodS  
Timmiella (De Not.) Limpr. is an haplolepidous  
Specimens were studied morphologically following  
genus of mosses placed in the monogeneric subfamily classical techniques for bryophytes, and mounted  
Timmielloideae in family Pottiaceae following Zander in Hoyer’s solution (Anderson, 1954). Microscopic  
(1993). Based on molecular analysis performed by characters were analyzed by using LM Arcano XSZ-  
Inoue & Tsubota (2014), Timmiella and Luisierella 100BNT, and SEM JEOL 5800 LV operating at 20  
Thér. & P. de la Varde were segregated to a separate KV. Characters illustrated using SEM were obtained  
family Timmiellaceae. The former genus includes ca. from samples mounted directly on double-sided  
13 species easily recognized by the presence of a well- tape and coated with gold-palladium. Spores were  
developed central strand in the stem, margin of leaf obtained from mature capsules by removing with  
plane and dentate, laminal cells bistratose at midleaf, alcohol, mounted directly on aluminum stubs, and  
adaxially bulging and abaxially flat, and peristomes subsequently coated with gold-palladium. Spores  
sinistrorse or straight, when present (Zander, 1993; were described following the concepts of McClymont  
Inoue & Tsubota, 2014). It is usually found growing (1955) and Punt et al. (2007).  
on soil or rocks, in arid lands and mountainous areas  
of North and South America, Europe, Asia and Africa  
(
Zander, 1993).  
In Argentina, three species of the genus have been  
described and recorded to date: Timmiella acaulon Taxonomic treatment  
Müll. Hal.) R.H. Zander, T. argentinica Broth. and  
reSulTS  
(
T. umbrosa (Müll. Hal.) Broth. (Matteri, 2003). Timmiella acaulon (Müll. Hal.) R. H. Zander, Bull.  
Originally, current T. acaulon was described by Müller Buffalo Soc. Nat. Sci. 32: 70. 1993. Fig. 1-4.  
(1879) as Trichostomum acaulon Müll. Hal. based on  
collections from province of Córdoba (in the center  
Tortella acaulon (Müll. Hal.) Broth., Nat.  
of the country) by German-Argentine botanist Paul Pflanzenfam. 1(3): 397. 1902. Trichostomum  
Lorentz.Later,itwastransferredtoTortella(Müll.Hal.) acaulon Müll. Hal., Linnaea 42: 320. 1879. TYPE:  
Limpr. by Brotherus (1902), and finally to Timmiella ARGENTINA. Córdoba, Colón, “Ascochinga, cum  
by Zander (1993). In making this last combination, Barbula umbrosa”, IX-1871 (syntype, not seen);  
Zander (1993) also proposed T. argentinica Broth., a “cum Barbula sedifolia et B. amphidiifolia aliis loci  
species described by Finnish botanist Viktor Brotherus circa Ascochinga”, IV-[1871, P. G. Lorentz s.n.]  
in 1918 based on samples collected in province of (syntypes, B not seen; NY 01448932!).  
Jujuy (northwestern Argentina), as a new synonym  
Timmiella argentinica Broth., Ark. Bot. 15(6): 3.  
of T. acaulon. Timmiella umbrosa has also been 1918. TYPE. ARGENTINA. Jujuy, Santa Bárbara,  
described by Müller based on samples collected in “Quinta prope Laguna de la Brea, loco salso ad  
Córdoba, and it is distinguished from T. acaulon, “salina”, 1901-1902, R. E. Fries 23” (Type, H!).  
mostly by its monoicous sexual condition. Despite the  
fact that T. acaulon has been well described by Müller,  
it has been sparsely recorded, and consequently poorly brown below. Stem simple to branching irregularly,  
illustrated so far. to 0.5 cm long, transverse section rounded,  
Plants forming cushions, yellow-green above,  
As part of a major project that aims to study central strand very strong, sclerodermis in 1 layer,  
the diversity of bryophytes in the Chaco province hyalodermis present, absent in older section of stem.  
(northeastern Argentina), a revision of herbarium Leaves incurved and tubulose when dry, spreading  
samples has been performed. As a result of the when moist, ligulate, 0.2-3.2 × 0.4-0.5 mm; upper  
discovery of a complete specimen, T. acaulon is lamina broadly channeled across leaf, margins  
rediscovery more than 100 years after its original incurved, plane at base, entire to weakly serrate at  
description, and its distribution range is extended to apex, lamina bistratose except along margins; apex  
northeastern Argentina. For the first time, a detailed acute; base broadened, sheathing; costa percurrent  
morphological description with illustrations in SEM tapering to apex, superficial cells isodiametric  
and LM of the taxon is here presented.  
and ventrally bulging, costal transverse section  
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Fig. 1. Illustration of T. acaulon. A: Habit with sporophyte, wet. B: Habit of male plant, wet. C: Two cauline  
leaves. D: Basal laminal cells. E: Distal marginal cells. F: Leaf apex. G: Stem cross section. H: Section at  
mid leaf. Scales= A-B: 2.5 mm (scale bar a); C: 2 mm (b); D-H: 100 µm (c) (Iriart 282-4, MO; illustration by  
P. Eckel).  
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Bol. Soc. Argent. Bot. 58 (4) 2023  
Fig. 2. Morphological characters of T. acaulon with a light microscope. A: Stem leaf. B: Leaf apex. C: Leaf  
margin. D: Detail of the costa section. E: Detail of lamina section. Scales= A: 0.1 mm; B-E: 50 µm. (Iriart  
282-4, CTES; photo by S. Jimenez)  
flattened to reniform, two stereid bands present, rectangular 10-20 × 7-8 µm, hyaline. Dioicous.  
ventral epidermis present, unistratose, guide-cells Perichaetia terminal. Seta ca. 1-1.5 cm long, reddish  
10-12 in 1(-2) layers, hydroid strands 2-3; upper brown, twisted clockwise, theca 2.8 × 0.8 mm, brown,  
laminal cells isodiametric, 9-10 × 6-8 µm; bulging elliptical, exothecial cells rectangular to oblong-  
ventrally and nearly flat dorsally, basal cells bulging- rectangular, 58-71 × 21-33 µm; annulus absent.  
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Fig. 3. Morphological characters of T. acaulon with a light microscope. A: Stem in transverse section. B:  
Detail of the stem central cylinder. C: Detail of peristome, annulus absent. D: Detail of shape, color and  
position of the capsule. Scales= A-C: 50 µm; D: 0.1 mm (Iriart 282-4, CTES; photo by S. Jimenez)  
Peristome teeth very short, straight. Spores spherical,  
Distribution and habitat. Originally T. acaulon  
4-19 µm diam., yellowish, finely verrucose, verrucae (Fig. 1-4) was described from central Argentina  
.2-0.3 µm wide, evenly distributed on the surface. in Córdoba province. Later, Zander (1993) with  
1
0
Laminal color reaction to KOH yellow.  
the synonymy of T. argentinica under T. acaulon  
expanded its distribution range northwards up  
Specimens examined. ARGENTINA. Chaco Prov.: to northwestern Argentina, in Jujuy province. In  
Libertador General San Martín Dept., Gral. San this work, its range of distribution is extended to  
Martín, 26° 32’16.33” S, 59° 20’54.12” W, on old brick northeast Argentina, in the Chaco province. It was  
wall, 6-III-1997, Iriart 282-4 (CTES, CTESN, MO).  
found growing in crevices of a shady old brick  
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Bol. Soc. Argent. Bot. 58 (4) 2023  
Fig. 4. Morphological characters of T. acaulon with a scanning electron microscope. A: Stem leaf. B: Laminal  
cells at base. C: Capsule, deoperculate. D: Detail of the capsule mouth. E-F: Detail of spores ornamentation.  
Scales= A: 0.1 mm; B-D: 100 µm; E-F: 10 µm. (Iriart 282-4, CTES; photo by S. Jimenez)  
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wall in an urban area in the locality of San Martín, BROTHERUS, V. F. 1902. Pottiaceae. In: ENGLER, A. &  
profusely fructified. Wet shaded ancient walls  
represent a singular habitat for mosses and ferns  
K. PRANTL (eds.), Natürlichen Pflanzenfamilien, pp.  
380-439. Wilhelm Engelmann, Leipzig.  
in urban environments from northern Argentina BROTHERUS, V. F. 1918. Contributions à la flore  
(
Iriart, 2015).  
bryologique de l’Argentina. Ark. Bot. 15: 1-15.  
INOUE, Y. & H. TSUBOTA. 2014. On the systematic  
position of the genus Timmiella (Dicranidae, Bryopsida)  
and its allied genera, with the description of a new family  
Timmiellaceae. Phytotaxa 181: 151-162. https://doi.  
org/10.11646/PHYTOTAXA.181.3.3  
auThorS conTribuTionS  
SJ determined, described and illustrated, the  
samples. RZ corroborated the identity of the IRIART, D. E. 2015. Comunidades vegetales urbanas del  
species. DI collected the samples. All authors  
contributed to the writing of the manuscript.  
norte de Argentina: Variabilidad florística y corológica.  
Doctoral Thesis. Universidad Nacional de Córdoba,  
Argentina.  
MATTERI, C. M. 2003. Los musgos (Bryophyta) de  
Argentina. Bryophyte Diversity and Evolution 24: 33-  
acKnowledgemenTS  
100. https://doi.org/10.11646/BDE.24.1.8  
Special thanks are owed to the staff of Servicio McCLYMONT, J. W. 1955. Spores of the Musci: their  
de Microscopía (UNNE), and to Patricia M. Eckel  
who generously provided the illustration. This  
research was supported by PICT 2019-00888.  
structure and significance in systematic research.  
Doctoral Thesis. University of Michigan, United States.  
MÜLLER, C. 1879. Prodromus bryologiae Argentinicae. I.  
Linnaea 42: 217-460.  
PUNT, W., P. P. HOEN, S. BLACKMORE, S. NILSSON &  
A. LE THOMAS. 2007. Glossary of pollen and spore  
terminology. Rev. Palaeobot. Palynol. 143: 1-81. https://  
doi.org/10.1016/j.revpalbo.2006.06.008  
ZANDER, R. H. 1993. Genera of the Pottiaceae: Mosses of  
Harsh Environments. Bull. Buffalo Soc. Nat. Sci. 32:  
I-VI, 1-378.  
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