Schlotheimia spinomitria D.F. Peralta & R. Ristow, 2017

Peralta, Denilson F. & Ristow, Rony, 2017, Schlotheimia spinomitria (Orthotrichaceae, Subg. Schlotheimia), a new species from Brazilian Cerrado, Phytotaxa 305 (3), pp. 217-221 : 218-220

Schlotheimia spinomitria D.F. Peralta & R. Ristow , sp. nov. ( Fig. 1 )

Type: — Brazil, São Paulo, São José do Rio Preto, pasto (29°49’11”S – 49°22’46”W), 14 April 2004, Peralta, D.F. & Jungbluth, P. 2367 (holotype SP!).

Plants medium sized, forming dense mats, dark green, occasionally blackish or brown to reddish at base. Stems creeping, often densely tomentose in the contact with the substrate by the abundance of rhizoids, branches short and erect; in crosssection as in the genus with outer 2–3 rows of cells small, thick-walled, inner cells large, firm-walled, central strand absent; rhizoids smooth. Stem leaves spaced by tomentum, oblong-lanceolate, plane, 1–1.2 mm long, apiculate. Branch leaves appressed and often spirally coiled about stem when dry, crispate at distal portion, wide-spreading when wet, ovate-oblong, 1.5–2.0 mm long, rugose at distal portion, apex with a small apiculum, base often with rhizoids; margins plane, entire; costa single, strong, channeled, short excurrent; median cells isodiametric, 7–8 μm wide, 6–7 μm long, rhombid to oblongrhombic, thick-walled; basal cells elongate, linear, thick-walled and porose, tubercula lacking; basal margin undifferentiated. Perichaetia terminal on short lateral branches, perichaetial leaves lanceolate, 2.0– 2.3 mm long, weak rugose at distal portion, apex with a small apiculum, base often with rhizoids; margins plane, entire; costa single, strong, short excurrent; median cells fusiform, thick-walled; basal cells elongate, linear, thick-walled and porose, tubercula lacking; basal margin undifferentiated. Seta elongate, 2–3 mm long, stout, smooth. Capsule exserted, erect, ovoid-cylindrical, 1.5–1.7 mm long; exothecial cells irregularly oblong-rectangular, thick-walled; stomata at urn base, superficial. Operculum long-rostrate. Peristome double, exostome reflexed when dry, papillose; endostome segments 16, shorter than exostome, or reduced. Calyptra campanulate, spinose, spines sometimes foliose, base often four lobed. Spores spherical, 12(–14)–18(–20) μm, sharply papillose.

Distribution and ecology: — Epiphyte on isolated trees in open Savana. These environments are rapidly decreasing because this vegetation is considered low diversity and are the first areas to be destroyed by livestock and farmers. As such, even when taking into account the large geographical distance between the specimens examined, we believe that this species should be considered threatened.

Etymology:—The epithet spinose refers to the calyptra ornamentation.

Discussion: — Schlotheimia spinomitria belongs to the subgenus Schlothemia by its large, mitrate and lobate calyptra. There are only two species described with hairy calyptra in this subgenus; Schlotheimia trichomitria and Schlotheimia compacta Müll. Hal. both from South America. The type specimens have been examined and both have long uniseriate hairs on the calyptra and here S. compacta is reduced to the the synonym of S. trichomitria . These species are unique with the calyptra ornamentation, but differ from the new species described here because their trichomes are very long, sometimes as long as the calyptra length, and uniseriate, wheres S. spinomitria has the spines short and multicellular. These species is differentiated according the key provided.

We checked the description of all species currently accepted in the genus and this calyptra feature is unique, even to the the family. Even though the epithet of the species S. spinulosa Broth. (1906: 273) (described from Peru) indicates “spines” the original description indicate the calyptra as “spinuloso-aspera”, probably rugose, and the photograph of type material BM000873395 (Accessed via the JSTOR online type image depository—http://plants.jstor.org/stable/viewer/10.5555/ al.ap.specimen.bm000873395) does not have trichomes visible on the calyptra.

After analysing near 1,400 specimens of Schlotheimia from Brazil and nearby countries from the follow herbarium of B, BM, H, ICN, NY, PC, PE, R, SJRP, SP and TUR. We found this new species represented only by three collections in the Brazilian savanna (cerrado), where it occurs on isolated trees on open places. It was not encountered among the many Brazilian collections from all regions and, apparently it does not survive on disturbed places as observed in several samples from these places, this way is therefore considered rare, and vulnerable and potentially threatened.

Additional specimens examined. Brazil. Bahia state: Pirituba , 3 April 1976, Vital, D.M. 6013 ( SP!) ; Goiás state, Luziânia , 17 May 1976, Vital, D.M. 6274 ( SP!) ; idem, Pirenópolis , 18 March 2006, Yano, O. & Sousa, M.A.R. 28619 ( SP!) .

Figures

FIGURE 1. Schlotheimia spinomitria. A) Plants with capsule. B–D) Vegetative leaves. E) Apex of vegetative leaf. F–H) Perichaetial leaves. I) Calyptra. J) detail of calyptra apex. K–N) Ornamentation of calyptra (from the holotype, drawing by DFP).).