Ann. Bot. Fennici 36: 271–283 ISSN 0003-3847 Helsinki 14 December 1999 © Finnish Zoological and Botanical Publishing Board 1999 Circumscription of the family Scapaniaceae, with segregation of the new family Diplophyllaceae (Hepaticae) Alexey D. Potemkin Potemkin, A. D., Department of Lichenology and Bryology, V. L. Komarov Botanical Institute, 2 Prof. Popov Street, St. Petersburg, 197376 Russia Received 4 May 1999, accepted 2 September 1999 Potemkin, A. D. 1999: Circumscription of the family Scapaniaceae, with segregation of the new family Diplophyllaceae (Hepaticae). — Ann. Bot. Fennici 36: 271–283. On the basis of phylogenetic analysis, the family Scapaniaceae Mig. is emended to include only the genus Scapania (Dumort.) Dumort. emend. Potemkin. The genus Macro- diplophyllum (H. Buch) Perss. is recognized as a subgenus in Scapania. The new com- binations Scapania subgenus Macrodiplophyllum (H. Buch) Potemkin and Scapania plicata (Lindb.) Potemkin are provided. A new family, Diplophyllaceae Potemkin, with two genera, Diplophyllum (Dumort.) Dumort. and Douinia H. Buch, is segregated from the Scapaniaceae as a group of different origins resulting in a different morphology. Douinia is distinguished as a genus derived from Diplophyllum and its rank as a sub- family is rejected. The distinctive characters of Delavayella Steph. are discussed. Seg- regation of Delavayellaceae R.M. Schust. and Blepharidophyllaceae (R.M. Schust.) R.M. Schust. from the Scapaniaceae is supported. Key words: Blepharidophyllaceae, Blepharidophyllum, Delavayella, Delavayellaceae, Diplophyllaceae, Diplophyllum, Douinia, evolution, hepatics, Macrodiplophyllum, Sca- pania, Scapaniaceae, taxonomy INTRODUCTION lies, Blepharidophyllaceae (R.M. Schust.) R.M. Schust. and Delavayellaceae R.M. Schust., and The family Scapaniaceae Mig. has in recent lit- that resulted in the delimitation of the Scapania- erature included two to four subfamilies. Grolle ceae with two subfamilies, Scapanioideae, with (1983) recognized within it four subfamilies, i.e. the genera Scapania (Dumort.) Dumort., Diplo- Scapanioideae, Douinioideae R.M. Schust., Ble- phyllum (Dumort.) Dumort., and Macrodiplophyl- pharidophylloideae R.M. Schust., and Delavayel- lum (H. Buch) Perss. (mostly distinguished as a loideae (R.M. Schust.) Grolle. Schuster (1961, subgenus of Diplophyllum) and Douinioideae, 1979, 1983) distinguished two of them as fami- with only Douinia H. Buch. 272 Potemkin • ANN. BOT. FENNICI 36 (1999) Phylogenetic study of the genus Scapania led I know, has never been placed as the basal genus me to elucidate the relationships of the major enti- of Scapaniaceae. The known interpretations of re- ties of Scapaniaceae with its type genus, Scapania. lationships of Scapaniaceae appear to be based Analysis of these relationships is provided below. on the concept of gradual transformation of the lophozioid ± indefinite keel and inflated perianth into the acute keel and compressed perianth of TAXONOMIC DISCUSSION Scapania. Apparently, on this basis Scapania usu- ally follows Diplophyllum in virtually all hand- Scapania books. I consider both genera as efficiently spe- cialized in different ways. The initial point for phylogenetic analysis of Sca- Accepting in general the system of Lophozia- paniaceae was definition of the basal genus. I con- ceae suggested by Schuster (1951), with the sec- sider Scapania as the basal genus of the family, tion Kunzeanae R.M. Schust. (i.e. Orthocaulis) since it demonstrates a greater diversity of evolu- of Orthocaulis (H. Buch) R.M. Schust. as the ba- tionary potential (Potemkin 1998). In that paper I sal group, I distinguish Tritomaria and Anastro- assumed Scapania as a genus derived from the phyllum as rather advanced groups to evolve from ancestral type intermediate between the family Scapania. Jungermanniaceae Rchb. (subfam. Lophozioideae Barbilophozia kunzeana (Huebener) Müll. Macvicar) and the family Gymnomitriaceae H. Frib. is exceedingly variabile in width of ventral Klinggr. A position close to the Gymnomitriaceae merophyte, cuticle papillosity, leaf shape (occur- was concluded because of discovery of 2–3-spi- rence of arctic forms with bilobed almost condu- ral elaters and 2–3-stratose capsule walls in Scapa- plicate leaves and reduced underleaves is remark- nia praetervisa Meyl. However, this may be not a able), its 3–4-stratose capsule wall combined with sign of an ancestral type but a result of adaptation many other characters, to convince me that Sca- to harsh ecological conditions of growth on bare pania is a genus derived from an ancestor related soil in an arctic and alpine environment. A simi- to this species. Barbilophozia kunzeana itself, lar structure of elaters is known for Nardia brei- however, is different from Scapania in the some- dleri (Limpr.) Lindb., Prasanthus jamalicus Po- what angulate gemmae, inflated perianths, mostly temkin, Marsupella alpina (Limpr.) Bern., M. bre- regular development of underleaves, and some vissima (Dumort.) Grolle, M. sparsifolia (Lindb.) other characters. I think the gemma shape was Dumort., and some other species of Marsupella apparently not strongly fixed at the base of the Dumort., mostly characteristic of “difficult”, bare evolution of Lophozioideae, and this lead to ap- soil habitats. These features of the elaters were pearance of ovoid gemmae in two evolutionary lin- also observed in Scapania scandica (Arnell & H. eages of Lophozioideae (Lophozia heterocolpos Buch) Macvicar var. argutedentata H. Buch (Po- (Hartm.) M. Howe and L. capitata (Hook.) Macoun temkin 1993) and S. spitsbergensis (Lindb.) Müll. s. lato) and in Scapania. On the basis of the high Frib. (Potemkin 1994). The complete absence of plasticity of the Barbilophozia kunzeana-like an- gemmae in all known gymnomitrioid taxa sup- cestor, the idea of perianth compression correlated ports the assumption of ecologically induced par- with leaf keel development seems possible. allelism of elater structure. On this basis a lopho- Analysis of the present distribution of Scapa- zioid origin of Scapania seems most probable. nia shows that the highest endemism and richest Relationships between Scapaniaceae and Lo- representation of diverse taxonomic groups is in phoziaceae have repeatedly been suggested (e.g., SE Asia. The few species known from the South- Buch 1928, Schuster 1951, 1974, Kitagawa 1965). ern Hemisphere (except the highly advanced sub- These authors considered the genera Tritomaria genus Macroscapania R.M. Schust.) are more or Loeske and Anastrophyllum (Spruce) Steph. less advanced representatives of the northern (Schuster 1951) as closest to Scapaniaceae. How- groups. Therefore Scapania is considered as a ever, before Potemkin (1998), Scapania, as far as genus of Laurasian origin. ANN. BOT. FENNICI 36 (1999) • Circumscription of the family Scapaniaceae 273 Macrodiplophyllum pania sphaerifera to elucidate a possible evolu- tion of Macrodiplophyllum through S. sphaerife- The genus Macrodiplophyllum (H. Buch) Perss. ra-Macrodiplophyllum microdontum “bridge”. (≡ Diplophyllum subgen. Macrodiplophyllum H. Scapania sphaerifera resembles M. microdontum Buch in most modern treatments) is considered in (1) ± sheathing and rounded leaf bases, (2) acute to be closest to Scapania. It includes three spe- distal keel sectors, (3) shape of ventral lobes, (4) cies, M. imbricatum (M. Howe) Perss., M. micro- spinous terminal cells of marginal leaf teeth and dontum (Mitt.) Perss., and M. plicatum (Lindb.) distribution of teeth to the leaf base, (5) leaf areola- Perss., occurring mostly in the area of the North tion, (6) cuticle structure, (7) multicellular gem- Pacific Arc. All species of Macrodiplophyllum mae with intersecting internal walls, (8) pattern have a scapanioid leaf dentition (if any), areola- of modification of gemmiparous leaves with char- tion, and insertion (short decurrent to arcuate), as acteristic elongation of marginal cells, (9) stem well as ventral intercalary branching (character- anatomy with frequent occurrence of ventral my- istic of many Asian Scapania), that provide rea- corrhiza infection, and (10) pluriplicate perianths son to associate them with Scapania rather than slightly contracted to the mouth, with the mouth with Diplophyllum. lobulate-ciliate (cf. Figs. 1 and 2; Buch 1928: fig. VI, Distinctions of Macrodiplophyllum imbrica- Konstantinova & Potemkin 1994: fig. 2). Moreo- tum, M. microdontum, and M. plicatum are not ver, they have similar ecological requirements and equivalent. If M. microdontum has a ± scapanioid were collected together in the Verkhoyansky appearance and stands close to S. sphaerifera H. Range (9.VII.1998 Akimova, LE). The character Buch & Tuom., the two other species resemble a of special significance connecting S. sphaerifera robust Diplophyllum due to the leaf bases long and M. microdontum is the 3–4-celled gemmae sheathing the stem, and more narrow lingulate fal- with intersecting internal walls. Regular produc- cate ventral lobes. tion of multicellular gemmae with intersecting I hypothesize evolution of Macrodiplophyllum internal walls is known within Scapaniaceae only through Scapania sphaerifera-Macrodiplophyl- in these species. lum microdontum “bridge” (which is considered The principal distinctions of Macrodiplophyl- below). Macrodiplophyllum microdontum is a spe- lum microdontum from Scapania sphaerifera are cies with a less specialized “macrodiplophylloid” (1) ± falcate ventral and particularly dorsal lobes, morphology, a broader range and probably a great- (2) stronger arched comissura,