Journ. HallOl'i BOI. Lab. No. 61 : 309- 332 (Dec. 1986) SCIAROMIADELPHUS A. ABR. & 1. ABR. - THE RELATIONSHIP BETWEEN EXTANT AND FOSSIL MOSS SPECIMENS R YSZARD O CHYRA ABSTRACT. Sciaromiadelphus lon!!.ifolius A. Abr. & I. Abr., a fossil moss from the Pliocene deposits from Bashkiria in the Soviet Union, is redescribed and illustrated . It is congeneric with and closely related to the extant Sciaromium barllellii Crum & Steere from Hispaniola, which is also redescribed and ill ustrated. The new genus Sciaromiella Ochyra is proposed and two new combinations, S . longifolia (A. Abr. & I. Abr. ) Ochyra and S. barllellii (Crum & Steere ) Ochyra, are made. Sciaromiadelphus A. Abr. & I. Abr. , a fossil moss genus is congeneric with the extant Sciaromiella , the latter having a priori ty over the former. Sciaromiella is considered to be closely related to Sciaromiopsis Broth., a monotypic genus from China. Sciaromiopsis is redescribed and ill ustra ted. It includes only S. sinellSLI (Broth.) Broth., and S. brevifolia Broth. is synonymous wit h the former species. S. nipponensis Sak. from Japan is di scussed and this species is inseparable from Brachy rhecium populeum (Hedw.) B., S. & G . var. populeum. T he fa milial placement of Sciaromiella and SCiaromiopsis is di scussed and they are placed in the newl y described su bfamily Sciaromiopsoideae Ochyra of the Donrichardsiaceae Ochyra. A key for genera and spec ies of Donrichardsiaceae is gi ven and the geographical affiliation of the Sc iaromiopsoideae is considered. INTRODUCTION Sciaromiade/phus A. Abr. & 1. Abr. is a fossil moss genus that includes only one species, S. longifolius A. Abr. & I. Abr., that have been found in the Pliocene moss assemblage of the K inelian deposits from Bashkiria in the Soviet Union (Abramova & Abramov (967). The moss was recovered from the unsurpassed well-preserved fossil remain s of considerable thickness (Abramov (965). Contrary to most fossilized moss specimens that have hitherto been reported, there is excellent preservation of plants in these Pliocene deposits and the Abramovs were able to examine cellular details of the leaves and to make transverse sections of the stems and leaves as with extant mosses. This resulted in an excellent description of S. /ongifo/ius and therefore an evaluation of its possible affinities with both fossil and extant taxa of mosses was feasible. Abramova and Abramov (1967) included Sciaromiadelphus in the Amblystegi­ aceae. However, they did not discuss the problem of the taxonomic position of this newly described genus and stated only that the general aspect of S. longifolius is compatible to that of some species of Drepanocladus, for in stance D. aduncus var. kneifJi.i or D. jluitans, especia Jl y in habit and leaf shape. On the other hand, the generic name suggests its si milarity and relationship to Sciaromium (Mitt.) Mitt., a genus characterized by having limbate leaves. During the course of my on-going revision of Sciaromium and potentiaJly related I Laboratory ot Bryology, Institute of Botany of the Polish Academy of Sciences, Lubicz 46, PL-31-512 Krak6w, Poland. 310 Journ. Hattori Bot. Lab. No. 61 I 9 8 6 genera with limbate leaves I critically re-examined the holotype of S. longifolius housed in the Komarov Botanical Institute in Leningrad (LE) and compared it to extant genera having limbate leaves, including Sciaromium and Sciaromiopsis Broth., genera that are currently placed in the Amblystegiaceae (Brotherus 1925; Vitt 1984). Special attention was given to Sciaromium bartlettii Crum & Steere, a species described from two collections from Hispaniola (Crum & Steere 1958). It soon became obvious that the fossil , Sciaromiadelphus longifolius, and the extant, Sciaromium bartlettii, shared many critical and taxonomically important characteristics, suggesting close relation­ ships and affinities between these two taxa, and their possible congeneric status. DESCRIPTION OF SCIAROMIADELPHUS LONGlFOLIUS (Fig. 1) Plants rather robust, rigid and wiry in texture. Stems elongate, 5- 8 cm long, si mple or sparsely fastigiately branched, somewhat curved at tips, in transverse section composed of 2- 3 rows of smaller, thick-walled cortical cells surrounding 5- 6 rows of larger, rather firm-walled FIG. I. Sciaromiadelphus longifolius A. Abr. & I. Abr. 1-3: leaves; 4: portion of side­ branch; 5: mid-leaf cells; 6: angular cells of the upper leaf; 7: upper marginal cells without border; 8: transverse section of the costa in the upper part; 9: transverse section of the costa in the median part; 10-11 : transverse sections of leaf borders; 12: transverse section of the stem (according to Abramova and Abramov 1967). R. OCHYRA: Sciaromiadelphus - relationship between extant and fossil mosses 3 11 inner cells, central strand lacking or inconspicuous. Leaves crowded and appressed at tips of stems and branches, rather loosely arranged below, erect to erect spreading, (3.0- )3.5- 4.0(- 5.0) mm long, (0.5-)0.8-\.0(- 1.3) mm wide, ovate-lanceolate and gradually long to filiform acuminate, straight or slightly secund, somewhat rounded to the insertion, not auriculate and non-decurrent; margins plane, entire to sli ghtly and distantly serrulate, bordered by 6--12 rows of narrow, elongate, thick -walled, brown cells in 2 layers; borders well-developed and conspicuous in older, lower leaves, reaching usually the apex and confluent with the costa or ending somewhat below the apex, in uppermost stem and branch leaves narrower and indistinct or lacking; costa single, terete, stout, 70-80/lm wide at base, sli ghtly tapered, percurrent to long excurrent as a stout, cuspidate point, in transverse section bi-convex, composed of uniform, small, thick-walled cells, and only sometimes with some ventral outer cells at the base larger than inner cells; lamina cells unistratose, frequently with bistratose, longi tudinal streaks extending as spurs from costa and margins or developing independently; upper median cells flexuose, somewhat prorate, linear-rhomboidal, becoming longer downwards, (26- )40-55(-60)/lm long, 8- 9/lm wide; basal cells wider and shorter in several rows, short-oblong to oblong-hexagonal, rather thin-walled, more lax, 15- 25 ~lm long, 10-13 /lm wide. Sexual organs and sporophytes unknown. The distinctive features of the monotypic fossil genus Sciaromiadelphus are erect to erect-spreading, ovate-lanceolate to lanceolate leaves that gradually taper into a long acumen and in general aspect resemble those found in a variety of Drepanoc/adus species; distinct, bistratose borders of the leaves composed of 6-- 12 rows of narrow, thick-walled, linear cells that are usually confluent with the percurrent to long excurrent costa; and linear-rhomboidal, flexuose and prorulose lamina cells. DESCRIPTION OF SCIAROMJUM BARTLETTlI (Fig. 2) Plants stiff, yellow-green or golden-green to brownish, glossy, in loose mats. Stems up to 6 cm long, prostrate, sparsely fastigiately branched, brown, naked, in transverse section composed of 2-3 rows of small cortical cells with incrassate walls and 5-7 rows of larger, rather firm-walled cells in an inner area, central strand absent or inconspicuous and obscure; paraphyllia none, pseudoparaphyllia not abundant, foliose to suborbicular, entire to irregularly serrulate. Leaves erect, densely set, sl ightly flexuose and twisted in the upper part of stem and branches when dry, \.9- 2.1 mm long, 0.8- 0.9 mm wide at the base, ovate-lanceolate, gradually tapering into a rather short acumen, flat or somewhat concave; margins plane, entire or si nuate to distantly indistinctly serrulate, bordered all around by 5- 10 rows of narrow, elongate, linear­ flexuose, thick-walled, yellowish-brown to brownish cells, not sharply demarcating from lamina cells, in transverse section bistratose, consisting of thick-walled, homogeneous cells; costa single, yellow, 95-110/lm wide at the base, gradually narrowed to the apex, percurrent to short excurrent, confluent with bistratose margins and forming bistratose, cuspidate point, in transverse section composed of uniform, thick-walled cells, bi-convex; lamina cells unistratose, occasionally with bistratose strands radiating from costa and margins as spurs, rather obscure, green to yellowish-green, Iinear-flexuose throughout the lamina, 60-110 /lm long, 8-9/lm wide, with moderately incrassate walls, papillose by projections of the upper ends; basal cells noticeably wider and shorter than upper cells, short rectangular to oblong-hexagonal, greenish to yellowish-green, ll- 14/lm wide, 40-55/lm long; cells at the insertion similar in shape, not coloured and not forming auricles. Sex apparently dioicous. Male gametangia bud-like, 312 Journ. Hattori Bot. Lab. No. 61 I 9 8 6 , . 2 01 22 19 j16 1\ ." J 20 18 00-0\ , \ F IG. 2. Sciaromium barllettii Crum & Steere. I: habit; 2: portion of branch when dry; 3--6: leaves; 7- 9: pseudoparaphyllia; 10: transverse sections of leaves; 11 : transverse section of the stem; 12: angular cells of the leaf base; 13: median leaf cells; 14: median leaf cells at margin; 15: perigonium; 16-18: outer perigonial bracts; 19-22: inner perigonial leaves [1-4, 7- 14 drawn from isotype (KRAM); 5- 6, 15- 22 drawn from paratype (MICH)] . R. OCHYRA: Sciaromiadelphus - re lationship between extant and fossil mosses 313 0.7- 0.8 mm long; outer perigonial bracts lingu late, truncate or broadly rounded at the apex, entire and irregul arly si nuose, 0.2- 0.4 mm long, 0.2-0. 3 mm wide; inner perigonial leaves broadly ovate-lanceolate , deeply concave, graduall y narrowed into a broad, short apex, 0.5- 0.6 mm long; antheridia few, claviform, short-stalked, about 250 JLm long; paraphyses few, hyaline, filiform, reach ing beyond the antheridia. Perichae ti a and sporophytes unknown . G ENERIC POSITION OF S CIAROMIUM BARTLETTlI The generic position of S. bart/ellii was one of the most problematic and difficult tasks of my revisionary study of Sciaromium. This sterile moss does not seem to fi t the concept of any extant genus of pleurocarpous mosses.