Research Article |
Corresponding author: Harold Robinson ( robinsoh@si.edu ) Academic editor: Peter de Lange
© 2020 Harold Robinson, G. Karen Golinski.
This is an open access article distributed under the terms of the CC0 Public Domain Dedication.
Citation:
Robinson H, Golinski GK (2020) Notes on Brachymenium in Guyana with a new species from Mt. Ayanganna. PhytoKeys 154: 11-17. https://doi.org/10.3897/phytokeys.154.39105
|
A relative of the African species described by Brotherus as Bryum perspinidens, has been discovered in Guyana with erect capsules and a short inner peristome. The Guyana material is recognized as a new species, and both species are placed in the genus Brachymenium. The characteristics that distinquish the genus are discussed with reference to the Guyana specimens of Brachymenium speciosum.
African relationship, Bryaceae, peristome, rostrate operculum
Study of bryophyte collections obtained during the Smithsonian Biological Diversity of the Guianas project, has revealed a number of interesting species. Among these are two two collections of a bryaceous moss with capsules identifiable as a Brachymenium Schwaegr., Spec. Musc. Suppl. 2(1): 131. 1824, with a leaf that superficially matches the illustration of Bryum perspinidens Broth. in the Brotherus treatments in the two editions (1904 and 1925) of Engler and Prantl. The only problems were that the Brotherus illustration was of an African species named as a Bryum. The spiniform teeth of the leaf margins were nevertheless similar, and a relationship seemed to be involved. As for the generic placement, the
Specimens in this study were obtained during the Smithsonian Biological Diversity of the Guianas Program conducted over a period of years from 1985 to 2014 (
A note with the specimens indicates that when they arrived in the US they were irradiated during the Anthrax scare of 2001.
The South American material includes one species that seems to be distinct from others from the Western Hemisphere (see for example
Guyana. Region: Potaro–Siparuni. Mt. Ayanganna, east face, plateau above second of four escarpments. 1380 m, 05°22.550'N, 059°58.350'W. Scrub forest on sandstone and peat, with Clusia, Pagamea and Sphagnum. Epiphyte; sporophytes green. 17 June 2001. H.D. Clarke 9299, with R. Williams, C. Perry, E. Tripp & J. Kelly (US).
Brachymenium ayangannensis H.Rob. & G.K.Golinski. A Leafy stem showing distorted leaves B distal part of leaves, showing well-developed pale margin and spiniform teeth on both margin and long-acuminate tip C remoistened erect capsule showing partially detached short-rostrate operculum D B. perspinidens (Broth.) H.Rob. & Golinski, distal part of leaf of holotype (from H) E tip of capsule mounted in Hoyer’s solution showing short exostome and lack of well-developed endostome. The photographs were taken using a Leica DM4B Compound microscope, using a 5× objective.
Stems up to 3 cm tall, leaves not closely spaced, rather firm in structure but contorted when dry and resistant to wetting. Costa percurrent into a long slender acumination, median cells narrowly oval, with firm walls showing slight porosity, mostly 80–100 μm long and ca. 30 μm wide, without shorter quadrate cells at base, margin with numerous rows of linear pale cells forming a strong border, border with numerous cells projecting as spiniform teeth, such spiniform teeth extending onto apical acumination. Synoicous? Seta pale yellowish-red, ca. 17 mm long, smooth. Capsules erect, ca. 2 mm long, with short hypophysis, operculum short-rostrate, higher than wide. Outer peristome teeth reddish, rudimentary, ca. 80 μm long, inner peristome a low pale membrane ca. 70 μm without projecting segments or cilia. Calyptra not seen. Spores ca. 10 μm in size.
Guyana. Region: Potaro–Siparuni. Mt. Ayanganna, east face, area near camp at base of fourth of four escarpments. Elev. 1545 m, 05°23.083'N, 059°58.550'W. Dense forest on sandstone and peat, with Euterpe, Clusia, and Brocchinia. Sporophytes green. On tree limb. H.D. Clarke 9551 with R. Williams, C. Perry, E. Tripp & J. Kelly (US).
The peristome teeth of the new species have proven extremely fragile, possibly because of the radiation treatment.
The spiniform teeth of the leaf margin are distinctive, but the manner in which they occur on the acuminate apical extension is reminiscent of the illustration by
The African species is well illustrated by
Bryum perspinidens
Broth., Bot. Jahrb. Syst. 24: 246. 1897. Britische Ostafrika, Seengebiet: Ru– Nssóro, 3300–3600 m (Uganda: Ruwenzori, heather forest 10–12000’), Scott Elliot 266, Sterile. Rhodobryum perspinidens (Broth.) Pócs, in Bizot & Pócs, Acta Bot. Acad. Sci. Hungaricae 25: 257. 1979 [1980]. With record of species from Tanzania, also sterile.
Placement of the new species in Brachymenium is based on the capsules being erect with an inner peristome being a low membrane lacking segments or cilia, the traditional distinctions of the genus. Recent DNA studies (
The latter species has been collected on a mountain near Ayanganna as indicated below.
Mt. Wokomung, Little Ayanganna, upper slopes of highest point of Mount Wokomunga massif. 5°5'8"N, 59°50'32"W. elev. 1525 m. Tepui scrub forest on sandstone and peat, with Schefflera, Clusia and Guadua. 5 July 2003, H.D. Clarke 10550, with R. Williams, C. Perry, J. Kelly, D. Gittens, S. Stern; Guiana. Mt. Wokomung, Little Ayanganna, upper slopes of highest point of Mount Wokomung massif. 5°5'8"N, 59°50'32"W. elev. 1525 m. Tepui scrub forest on sandstone and peat, with Schefflera, Clusia and Guadua, elev. 1525 m. 5 July 2003, H.D. Clarke 10575, with R. Williams, C. Perry, J. Kelly, D. Gittens, S. Stern. Guiana. Mt. Wokomung, Little Ayanganna, upper slopes of highest point of Mount Wokomung massif. 5°4'53.1"N, 59°50'26.1"W. elev. 1525 m. Tepui bog on sandstone and peat, with Brocchinia, Bonnetia and Rapatea, elev. 1660 m. 6 July 2003, H.D. Clarke 10576, with R. Williams, C. Perry, J. Kelly, D. Gittens, S. Stern. Mt. Wokomung, area above third of four escarpments, 1 km NE of Mt. Wokomung, 5°4'30"N, 59°51'15"W. elev. 1490 m. dense forest on laterite, with Clusia, Euterpe and Licania, elev. 1490 m. 8 July 2003, H.D. Clarke 10802, with R. Williams, C. Perry, J. Kelly, D. Gittens, S. Stern. The material shows the additional feature of the species, the multistratose leaf margin with teeth on the margin and upper and lower surfaces. The species is otherwise reported from Suriname, Ecuador, and supposedly described from Jamaica (Maracaibo, Venezuela?)(
Brachymenium speciosum (Hook. & Wils.) Steere. A Part of leafy stem showing distorted leaves B tip of leaf showing thickened margin with teeth on margin and upper and lower surfaces, some of these appearing as double teeth C capsule showing rostrate operculum D peristome teeth mounted in Hoyer’s solution, showing elongate exostome teeth erect on one half and reflexed on other half, the latter showing endostome lacking cilia and segments. The photographs were taken using a Leica DM4B Compound microscope, 5× objective.
We thank Eric Schuettpelz, Chair of the Department of Botany, NMNH, for generously allowing us to use his lab and for providing ongoing support of our work on the bryophytes. H. David Clarke collected the specimens of Brachymenium ayanganna and B. speciosum while exploring the mountaintops of Guyana, funded by grants from National Geographic (Grant #6622-990) and the Smithsonian Institution’s Biodiversity of the Guiana Shield Program under the direction of Vicki Funk and Carol Kelloff. We appreciate the help of Sanna Laaka-Lindberg, Collection Coordinator of H Bryophyte Herbarium (Helsinki), for providing the type specimen of Brachymenium perspinidens, and Alice Tangerini, resident artist in the Department of Botany, NMNH, for expertly constructing the plates. Our manuscript greatly benefited from a thorough review by Blanka Aguero and an anonymous reviewer.