Botanica Pacifica. A journal of plant science and conservation. 2017. 6(2): 49–51 DOI: 10.17581/bp.2017.06206 On the identity of Riccia vulcanicola Eb. Fisch. (Marchantiophyta: Ricciaceae) Eugene A. Borovichev 1,2 * & Vadim A. Bakalin 3 Eugene A. Borovichev 1,2 * ABSTRACT e­mail: [email protected] The study of type specimen of Riccia vulcanicola Eb. Fisch. recently described from Vadim A. Bakalin 3 Africa (Rwanda) has revealed its identity with R. nipponica S. Hatt., the imper fectly e­mail: [email protected] known East Asian taxon. Two names are synonymized under R. nipponica having priority over R. vulcanicola. The present result considerable extends the known 1 area of the species and expects its distribution in some wetter areas of Medi ter­ Polar­Alpine Botanical Garden­Institute ra nean and mountain system of equatorial and subequatorial Africa. of the Kola Science Center of RAS, Kirovsk, Russia Keywords: Riccia vulcanicola, Riccia nipponica, Ricciaceae, taxonomy 2 Institute of Industrial Ecology Problems РЕЗЮМЕ of the North of the Kola Science Center of RAS, Apatity, Russia Боровичев Е.А., Бакалин В.А. О статусе Riccia vulcanicola Eb. Fisch. (Marchan tiophyta: Ricciaceae). Изучение типа Riccia vulcanicola Eb. Fisch., не­ 3 Botanical Garden­Institute FEB RAS, дав но описанного из Африки (Руанда) вида, показало его идентичность с ма­ Vladivostok, Russia ло из вестным восточноазиатским R. nipponica S. Hatt., в синонимы с которым све­ дено первое название. Учитывая существенное расширение известного ареала R. nipponica, можно ожидать его находок также в некоторых районах Сре ди зем­ * corresponding author но мо рья и горных системах экваториальной и субэкваториальной Африки. Ключевые слова: Riccia vulcanicola, Riccia nipponica, Ricciaceae, таксономия Manuscript received: 09.08.2017 Review completed: 09.11.2017 Accepted for publication: 21.11.2017 Published online: 26.11.2017 Riccia vulcanicola Eb. Fisch. was described from Virunga were combined from several optical sections using the soft­ Volcanoes area of Rwanda by E. Fischer (1993) as the new ware package Helicon Focus 4.50 (Kozub et al. 2008). Ad­ species of the R. crystallina complex. The taxa of this comp­ di tionally, a type specimen of Riccia nipponica S. Hatt. from lex are characterized by intergrading morphology that re­ NICH and other specimens of the species from VBGI and quires considerable amount of the material to find more or KPABG were studied. less stable differentiating features. The most pronounced Results and discussion example is R. cavernosa which for a long time has been re­ garded as conspecific with R. crystallina until Jovet­Ast According to the protologue (Fischer 1993) R. vulcanico­ (1964) showed two taxa are distinct, although closely re­ la differs from R. crystallina in: 1) thalli 2–4­times furcate, lated. R. nipponica is another taxon of the same complex we mostly with segments 2–3 mm wide, rosette incomplete, have recently reviewed (Borovichev & Bakalin 2015). Since segments eventually overlapping vs thalli (2–)3–4­times being involved into study of this group, we were in teres ted fur cate, soon breaking into two semirossetes, segments to test the status of African endemic R. vulcanicola that (due 1.5–2.5 mm wide in R. crystallina; 2) air­chambers in 2–3 to original description) seemed to be very closely related to super posed stra ta, 125 μm wide at base, polygonal vs air­ East Asian R. nipponica. The main goal of the present ac­ cham bers rather narrow canals, in one stratum (locally 2) in count was to check the status of the former and its relation­ R. crystal li na; 3) up per thallus surface collapsed and promi­ ships with the latter. The recent occasion to study the iso­ nently la cunose, pores enlarging, thallus spongy vs epider­ type of R. vulcanicola in G has inspired the present paper. mis persistent, pores not or tardily exposed in R. crystallina; 4) ventral scales tiny vs small, ephemeral narrowly lineate Materials and Methods distinct ventral scales in R. crystallina; 5) ventral tissue pres­ Specimens of Riccia vulcanicola are kept in the type collec­ ent in median part of thallus only, flanks formed by large tion in Conservatoire et Jardin Botanique de la Ville de air­chambers vs ventral tissue extended almost to lateral Genève (G). Dry thalli and spores were inspected with a margins of segments, flanks without large air­chambers in light microscope. The spore surface was analyzed with Leica R. crystallina; 6) spores more or less perfectly areolate, with DMLS light microscope, equipped with Canon EOS1100D large areolae (10–)12–15(–17) μm in diameter, their edges ca me ra and NDPL­1(2X) optical adaptor. In order to better not extending to the wing vs spores more or less perfectly il lust rate the three­dimensional object, photomicrographs areolate, with small areolae, approximatelly 12 μm in diam­ ©Botanical Garden-Institute FEB RAS. 2017 49 Borovichev & Bakalin eter, the aereo lation extended clearly to the wing. The spe­ The differentiations of this species from R. crystallina are: 1) cies was re ported from several localities in Rwanda and its spore distal face with 4–5 large (8–10(–12) μm in diame ter), general distribution was regarded as imperfectly known. complete alveoli across spore diameter vs 7–10 complete The isotype (G 00064713) consists of many thalli in small alveoli across spore diameter in R. crystallina; 2) pre­ ro settes or semirosettes incrusted by fine soil. Plants have sence spine in center of alveoli, but not in angles vs with R. cavernosa­like habit. The description prepared from the tubercles or spines at the angles in R. crystallina; 3) width of type is as following: thalli medium­sized, 1.5–3 mm wide, spores wings: (4–)6–8(–12) μm vs 3–4(–6) μm in R. crystal­ 5–7 mm long; 2–4 times furcate; ultimate branches short, lina; 4) color of thallus upper surface light green to some­ wide, obcordate; apex thick, rounded to emarginate; up­ what bluish green, in older parts becoming whitish or yel­ per surface light green to gray green with whitish portions lowish vs bluish to grayish but turning whitish upon drying (Fig. 1); spongy, not or slightly lacunose towards the apex in the field inR. crystallina. and sparsely lacunose in older parts. Ventral surface green or It should be noted that one of the most characteris­ yellowish; thallus midrib fleshy, 250–550 μm thick in cross­ tic features of R. nipponica is in the spore surface sculpture, section. Rhizoids are smooth and pegged, hyaline, covering where in the center of each alvelola one prominent and ventral surface of midrib of thallus. Sporangia are numer­ sharp spine is developed. This distinct feature was unfortu­ ous, dorsal, protruding dorsally. Spores are 50–65(–72) μm na tely not mentioned in original description of R. vulcanicola in diameter; light brownish; distal surface alveolate, with (Fischer 1993) nor depicted, although is obvious both in laminae forming 3–5 complete, rounded alveoli across the type and other materials of the taxon. As it is evident the face, 10–14 μm in diameter; lamellae thin and low, usually dif feren tiating features of R. niponica from R. crystallina are with a spine in the center of each alveola; proximal surface the same with differentiation of R. vulcanicola from the lat­ similar to distal surface, with a distinct trilete scar; wings ter. The descriptions and morphology observed in the types 6–10 μm wide; wing margin crenulate (Fig. 2). of R. nipponica and R. vulcanicola are the same that requires The key features mentioned in the description above synonymyzing both name under R. nipponica described 40 as well as listed in the protologue (Fischer 1993) are the years before R. vulcanicola: same with East Asian R. nipponica S. Hatt. The latter was Riccia nipponica S. Hatt., J. Hattori Bot. Lab. 9: 38. described in 1953 by S. Hattori from Obi in Miyazaki Pre­ 1953. – Riccia vulcanicola Eb. Fisch., Trop. Bryol. 8: 74. f. fecture of Japan (Shimizu & Hattori 1953) as belonging to 1–2. 1993. syn. nov. Riccia crystallina­complex. For a long time, R. nipponica was The ecological requirements of African and East Asian treated as a Japanese endemic and the taxon merely com­ po pulations of the species seem to be somewhat similar. As mon there (Higuchi 2011, Katagiri & Furuki 2012). Recent­ it was showed by Borovichev & Bakalin (2015) the species ly, the species was found in China (Guizhou Province) and inhabits fine earth in sandy loam stream banks and (more in the Russian Far East (Khabarovsk Territory) (Bakalin et rarely) clayish soil in agricultural field edges, with surround­ al. 2015, Borovichev & Bakalin 2015, 2016). The distinc­ ed communities varying from wet evergreen subtropical tions of R. nipponica from closely related R. crystallina and forests in the South to the hemiboreal ‘Ussuri’ taiga in the R. ca ver no sa are provided by Borovichev & Bakalin (2015). Figure 1 Riccia vulcanicola Eb. Fisch. from isotype G 00064713. A, B – habit of plants. Scale bars: 1 mm for both 50 Botanica Pacifica. A journal of plant science and conservation. 2017.6(2): 49–51 The identity of Riccia vulcanicola (Marchantiophyta: Ricciaceae) North (the latter locality was expected as hav­ ing re lict nature). In known localities in Africa (where the ecology of the species is likely im­ perfectly known) the species was observed in fine soil along trail, thus in the conditions rath­ er similar to that observed in agricultural fields. Taking into account the elevations (2700–3000 m a.s.l.) the mountain subtropical to oreotem­ perate character of surrounded communities may be also expected (that is similar to those observed in mountainous Guizhou Province of China).