J Hallori BOI. Lab. No. 97: 249-261 (Jan. 2(05)

STUDIES ON THE () VI: INFRAGENERIC CLASSIFICATION IN ASTERELLA

I DAVID G. LONG

ABSTRACT. A review and assessment are presented of the three existing classifications of species within the genus Asterella. Based on recent morphological and molecular studies additional charac­ ters such as spore colour and ornamentation are considered important in classification. A new sub­ generic classification is presentee!, which groups the 48 provisionally accepted species into five sub­ genera, Asterella, Saccatae, Wallichianae, Phragmoblepharis and Craciles. Subgenus Asterella is di­ vided into two sections, Asterella and Brachyblepharis, subg. Wallichianae into two sections, Wal­ Uchianae and Cal!fornicae, the latter described as a new section containing only A. eaU/arnica. Subg. Phragmoblepharis cannot be satisfactorily divided into sections at present. A key is provided to the subgenera and sections along with descriptions and a list of accepted species in each.

INTRODUCTION The genus Asterella P.Beauv. is the second largest genus of (after Ric­ cia) with approximately 80 species according to Bischler (1998) and is almost world-wide in distribution, but it remains inadequately known in many parts of the world. Recent as yet unpublished revisionary work on Asterella in Eurasia and South and Central America (Long, 2000; Long, in press; Long, in prep.), as well as molecular phylogenetic work on a range of species (Long, Moeller & Preston, 2000) has increased knowledge and under­ standing of the genus sufficiently to attempt a new classification of the species. The genus is now considered to contain about 48 species, but this will be further reduced when Aus­ tralasian species are revised. The recent studies have demonstrated that the existing classifi­ cations are both incomplete and inadequate particularly in the characters they incorporate, and that there are additional characters which can be utilised and which may more accu­ rately reflect affinities and phylogeny of species. It is therefore intended that the new classi­ fication will be both of practical value in grouping species and at least in part reflect phy­ logeny although the phylogenetic studies only included a selection of species.

PAST CLASSIFICATIONS Three classifications of species of Asterella have been published, the first two under the synonymous genus Fimbriaria Nees, by Gottsche, Lindenberg & Nees (1844- 1847) and Stephani (1898- 1900) and the most recent by Grolle (1976, 1989). Other recent treat­ ments such as that by Schuster (1992) are based on Grolle's system. The three classifica­ tions are shown in Tables I, 2 and 3, and are considered in turn.

1. Gottsche et al. (1844- 1847) The first classification of the genus (Table I) was published by the three leading Euro-

I Royal Botanic Garden, Edinburgh EH3 5LR, u.K. 250 1. Hattori Bot. Lab. No. 97 2 0 0 5

Table 1. Classification of species of Fimbriaria Nees by Gottsche, Lindenberg & Nees (1844- 1847).

I. Species genuinae, perianthio involucram §2. Perianthia radiata, i.e. horizontaliter evidenter superante. ( = Fimbriaria subgenus divergentia. [pseudoperianth radiating, i. e. Fimbriaria) diverging horizontally ] fpseudoperianth clearlv exceeding involucre] 14. F raddii Corda § I. Perianthia dependentia. 15. F wallichiana Lehm. & Lindenb [pseudoperianth hanging down] 16. F sanguinea Lehm. & Lindenb. 17. F viridis Lehm. & Lindenb. I. F boryana Mont. 18. F abyssinica Gottsche. 2. F pi/osa Taylor 3. Ffragrans Nees 11. Subgenus Brachyblepharis Gottsche et al. 4. F umbonata Wallr. Perianthii 6- 8-fidi laciniae involucro paulo 5. F saccata Nees longiores. fpseudoperianth 6- 8:fid, lobes scarcely 6. F marginata Nees exceeding involucre] 7. F nepalensis Nees 8. F australis Taylor 19. F chilensis Nees & Mont. 9. F nana Lindenb. 20. F venosa Lehm. & Lindenb. 10. F lindenbergiana Corda 21. F leptophylla Mont. I I. F tenella Nees 22. F af'ricana Mont. 12. F blumeana Nees 13. F elegans Spreng. pean hepaticologists of the day, Gottsche, Lindenberg and Nees von Esenbeck (1844- 1847) in their monumental Synopsis Hepaticarum. A total of 22 species of Fimbriaria were treat­ ed (as well as Rhacotheca azorica Bisch. which was kept as a separate genus, but is now synonymized under Asterella africana) from all continents of the world. Seven of their Fimbriaria species are now considered to be synonyms of other Asterella species. Al­ though they used only two characters (pseudoperianth exsertion and orientation), these proved to be very informative characters and their classification is a good foundation for later work. Subgenus Brachyblepharis was described in that work and is still recognised (as a section) and still contains the species they allocated to it.

2. Stephani (1898- /900) Stephani was a prolific author who had access to many new collections in the late 19th and early 20th centuries, such as the herbarium of E. Levier. His major work was the 6-vol­ ume Species Hepaticarum in the first part of which (Stephani, 1898- 1900) he treated 69 species of Fimbriaria (Table 2). Nineteen of these were described as new species, though no key was provided, and with modern taxonomic revision 33 of these are now considered to be synonyms of others. In the final sixth volume (Stephani, 1917- 1925) he added a fur­ ther 22 species of Fimbriaria. His "Obersicht der Arten" (conspectus of the species) arranged the species into four main groups based on carpocephalum shape and then into IS smaller groups based on the shape of the ventral scale appendages, but did not in any way D. G. LONG: Studies on the genus Asterella (Aytoniaceae) VI 251

Table 2: Classification of species of Fimbriaria Nees by Stephani (1898- 1900).

A. Capitula disciformia. 34. F khasiana. a. appendicula squamarum brevia, subovata 35. F bachmannii. I. F. leptophylla . 36. F violacea. 2. F. incrassata. 37. F pilosa. 3. F. venosa. 38. F. vesicu/osa. 4. F. raddii. k. appendicula setacea. b. appendicula lanceo/ata. 39. F californica. 5. F. blumeana. 40. F echinella. 6. F. zollingeri. 41. F abyssinica. 7. F. viridis. 42. F sanguinea. c. appendicula dentata vellaciniata. 43 . F multiflora. 8. F. angusta. 44. F. elegans. 9. F. maculata. 45. F. cubensis. 10. F. wallichiana. 46. F bo/anderi. d. appendicula sefacea. 47 . F. stahlii. 11. F atrispora. 48. F lateralis. e. capitula maxima, squamae ignotae. 49. F linearis. 12. F gigantea. 50. F commutata B. Capituli centrum hemisphaericum. 51. F austinii. f. appendicula dentata vellacerata. C. Capitula distincte conica (haud alle umbonata) 13 . F lindmannii. 1. appendicula magna, ovata, obtusa. 14. F. volkensii. 52. F miilleri. IS. F nepalensis. 53. F australis. 16. F africana. 54. F conocephala. 17. F pringlei. 55. F whiteleggeana. 18 . F. muscicola. m. appendicula lanceolata. 19. F wrightii. 56. F caucasica. 20. F persica. 57. F tasmanica. g. appendicula maxima, late ligulata, acuta 58. F subplana. 21. F drummondii. 59. F tenella. 22. F longebarbata. 60 . F mandonii. h. appendicula brevia, oblonga velovata. 61. F macropoda. 23. F. macounii. n. appendicu/a setacea. 24. F canelensis. 62. F. lindenbergii. 25. F. angolensis. 63. F setisquama. 26. F innovans. 64. F. preussii. 27. F vulcanica. o. appendicu/a dentata i. appendicula lan ceo/ata. 65. F. chilensis. 28. F tenera. D. Capitula alte umbonata. 29. F dissoluta. 66. F a/pina. 30. F parvipora. 67. Ffragrans. 31. F wilmsii. 68. F nudata. 32. F marginata. 69. F palmeri. 33. F boryana. 252 1. Hattori Bot. Lab. No. 97 2 0 0 5

Table 3. Classification of species of ASferella P.Beauv. by Grolle (1976, 1989).

Subgenus Asterella Subgenus Phragmoblepharis Grolle TYPE: A. lenella (L.) P.Beauv. Section Phragmoblepharis Other species: A. gracilis (EWeber) Underw. TYPE: A. elegans (Spreng.) Trevis. Other species: A. lateralis M.Howe Subgenus Brachyblepharis (Gottsche et al.) Grolle TYPE: A. lepfophylla (Mont.) Grolle Section Pappiae Grolle Other species: A. abyssinica (Gattsche) Grolle TYPE: A. pappii (Gala) Grolle A. a{ricana (Mont.) A.Evans Other species: A. persica (Steph.) M.Howe A. chi/em'is (Nees & Mont.) A.Evans A. dissoluta (Steph.) Grolle Section Lindenbergianae Grolle A. dominicensis S.W.Arnell TYPE: A. lindenbergiana (Nees) Arnell A. khasyana (Griff.) Pande et al. Other species: none . A. fen era (Mitt.) R.M.Schust. A. venosa (Lehm. & Lindenb.) A.Evans Section Saccatae Grolle TYPE: A. saccafa (Wahlenb.) A.Evans Other species: none.

build on the earlier classification of Gottsche et al. (1844- 1847). Unfortunately, carpocephalum shape is dependent on maturity and many of Stephani's specimens were inadequate or immature and his observations were often of poor quality. As a result many related species and synonyms (e.g. taxa belonging to subg. Brachyble­ pharis) ended up in several different groups. This classification, far from being an advance on the earlier one, is therefore of little value in arranging the species.

3. Grolle (1976, /989) The third system is that published quite recently by Grolle (1976, 1989), in which he recognised three subgenera: Asterella, Brachyblepharis and Phragmoblepharis, the last subdivided into four sections (Table 3). Grolle used a much wider array of characters, in­ cluding thallus anatomy, ventral scales, carpocephalum shape, involucre, pseudoperianth structure, spore colour and primary spore ornamentation. His treatment is limited by the narrow range of taxa covered, and some characters were not fully utilised e.g. pseudoperi­ anth structure, capsule dehiscence, elater spiralling and spore ornamentation and in addi­ tion no molecular data were available to him. However, it provides an excellent basis for the new classification presented below.

EVIDENCE FOR A REVISED iNFRAGENERIC CLASSIFICATION During course of revising Eurasian and Neotropical species of Asterella (Long, 2000; Long, in prep.; Long, in press) a wide range of morphological characters have been studied in detail for 26 species (more than half the total number now accepted). A large number of these are discontinuous characters which are particularly useful for grouping species to­ gether. These characters are summarized below and are grouped into three categories. Table 4. Summary of subgeneric differences in Asterella. p-a= par-autoicous; t-a= terminal-autoicous; v-a = ventral-auto- icous.

Wallichianae Saccatae Phragmoblepharis Asterella Graciles !:l 0 Thallus texture ± xeromorphic xeromorphic xeromorphic hygromorphic ± xeromorphic r Branching mostly terminal mostly terminal mostly terminal or terminal & ventral mostly terminal 0z c:: mostly ventral [/) ;::' No. ventral scale appendages 1 ( ~2) or 2-4 (1 ~)2 111 ~2 1 ~2 0- (ii' Sexual condition dioicous p-a/t-a p-a/v-a p-a/t -a/v-a p-a en 0 :::l Carpocephalum shape hemispheric tall-hemispheric hemispheric flat, umbrella-shaped hemispheric ::r to conical or hemispheric (I)

(I) Involucre free margin entire or deeply cleft deeply cleft entire/c1eft/emarginate entire cleft "":::l "en Pseudoperianth lobes free/united united united united free free :... Pseudoperianth constriction not constricted constri cted not constricted not constricted not constricted '" Pseudoperianth division depth 60% 50% 50~65% 50% 80% '"os ~ Capsule lid irregular irregular irregular irregular regular ~ Spore colour brown, red-brown black/brown-yellow brownlred-brownlpale yellow/orange-yellow yellow 0 :::l or yellow yellow Oi' Cl Spore primary ornamentation ridged ridged regularly areolate regularly areolate irregularly (1) ( distal) areolate ~"' Spore ornamentation uniformity uniform uniform uniform non-uniform uniform ~ Spore shape trilete trilete trilete trilete alete Elater spirals 1( ~2) 2 1 ~2 2 3(-4)

N V> W 254 J. Hattori Bot. Lab. No. 97 2 0 0 5

Table 5. Differences between and A. tenel/a.

Asterella gracilis Asterella ten el/a

Xeromorphism xeromorphic hygromorphic Smell non-aromatic aromatic Ventral scale appendages not constricted constricted Pseudoperianth lobing to base to just below middle Pseudoperianth lobe margins flat recurved Pseudoperianth lobe apex flat, finely pointed boat -shaped, blunt Involucral lobing deeply cleft undivided Capsule lid circular, unlobed irregular, lobed Spore diameter 55- 7O .um 86- 12O .um Spore shape alete trilete Spore areolae irregular, incomplete regular, complete Spore areola diameter 9- 17 .u m 18- 27 .um Elater spirals mostly 3-spiral mostly 2-spiral

i) Vegetative characters ofgametophyte Thallus texture ranges from hygromorphic to xeromorphic. In hygromorphic taxa such as Asterella africana the thallus is thin and delicate with large air chambers in over­ lapping layers; in xeromorphic taxa such as Asterella persica the thallus is thick and leath­ ery and assimilation tissue spongy with small irregular air chambers. In a few species, the condition can be rather intermediate. Branching: branches mostly terminal dichotomies or ventral intercalary, arising from lower surface of midrib. Both may occur in many taxa, but usually one type predominates. Ventral scale appendages: these vary in number from one to 4 per scale, and vary in shape from linear to lanceolate or oblong, and the apex may be acuminate, acute or obtuse. ii) Reproductive features ofgametophyte Sexual condition appears to be a remarkably constant character for all Asterella species, although it is not always visible at certain times of the year, and many early de­ scriptions were inaccurate. Only two species are considered to be dioicous (Asterella cali­ fornica and A. wallichiana), the rest show three distinct types of autoicy as defined by Long (1999): par-autoicous, terminal-autoicous and ventral-autoicous, according to the po­ sition of the androecia in relation to the archegoniophore. Carpocephalum shape ranges from flat or umbrella shaped to hemispheric in many species or conical in a few species; this must be observed at maturity as young carpocepha­ la can be quite different in shape. Involucre: the involucre in Asterella encloses the archegonia and later the ; it may be undivided, emarginate or deeply cleft. Pseudoperianth lobes: these are either completely free or remain fused at their tips. Pseudoperianth constriction: in a few species of Asterella the lobed part of the pseudoperianth is laterally compressed especially when young, and strongly constricted at D. G. LONG : Studies on the genus ASferella (Aytoniaceae) VI 255

the junction of the lobes and base. Pseudoperianth division depth: in most species the depth of lobing is 50 to 65% but in Asterella gracilis it is lobed almost to the base (80%).

iii) Sporophyte characters Spore colour and ornamentation under SEM are now known to be very useful taxo­ nomic characters in many genera of Marchantiales (Bischler, 1998) and this is especially true in Asterella (Long, 1998). Colour appears to be constant in most species and can range from black to brown, red­ brown, orange or yellow. Spore shape shows two distinct types, trilete with a conspicuous trilete mark on the proximal face and alete where there is no trilete mark as is shown only in A. gracilis. Similarity of sculpturing on distal and proximal faces clearly divides species into two groups: those where the ornamentation is similar and those in which it is dissimilar. Ornamentation of distal surface: species fall into three groups, those with a ridged surface, those which are regularly areolate and those which are irregularly or incompletely areolate. These spore types have been described and illustrated by Long (1998) who classified Asterella spores into 8 well-defined groups. Other spore characters such as fine structure of the areolae and muri and the presence of equatorial pores were also of value in distinguish­ ing species. Long (1998) also found that these spore groups supported several well-known species groupings in the genus, such as the species placed in subg. Brachyblepharis which all have yellow spores with similar types of ornamentation. One important grouping, that of A. tenella (the type species of Asterella) with A. gracilis, both placed in subg. Asterella by Grolle (1976, 1989), is contradicted by the spore evidence where the spores are striking­ ly different (Long, 1998). This is now corroborated by a range of morphological differ­ ences (Table 5) and as a result A. gracilis has now been transferred to its own subgenus Craciles (Grolle & Long, 2000).

iv) Evidencefrom molecular studies Long et al. (2000) carried out a phylogenetic reconstruction of Asterella and other genera of Aytoniaceae using two chloroplast genes (matK and trnL) and the results provid­ ed considerable insight on relationships both at genus and species level in the family. The two main conclusions from this study were that (a) Asterella was shown to be paraphyletic with , , and all nested within it, but it was still considered convenient to distinguish Asterella as a genus on the basis of its pseudope­ rianth; the other four genera are postulated to have lost their pseudoperianth by three sepa­ rate evolutionary events; (b) the molecular c1ades gave strong support for the species groupings based on spore colour and ornamentation, and supported the five main groups which are now recognised as subgenera.

REVISED INFRAGENERIC CLASSIFICATION OF A S TERELLA The revised classification is presented below as a key, descriptions of subgenera and 256 J. Hattori Bot. Lab. No. 97 200 5 sections, and a list of the recognised species in each group and a summary of their geo­ graphical range. The differences are also summarized in Table 4.

Key to subgenera and sections of Asterella 1. Pseudoperianth lobes free at maturity; spores yellow to orange-yellow ...... 2 + Pse udoperianth lobes remaining firmly joined at apex ; spores brown, red-brown to black or yel- low...... 4 2. Involucre deeply cleft; pseudoperianth lobed almost to base; capsule lid disc-like, not fragment­ ing; spores prox imally apolar, distally irregularly areolate...... subg. Graciles + Involucre undivided; pse udoperianth lobed almost to 50%; capsule lid fragmentin g; spores prox- imally polar, distally with regular areolae or (in A. blumeana) with bulging 'crown ' ...... 3 3. Mature carpocephala hemispheric ...... subg. Asterella sect. Asterella + Mature carpocephala flat or umbrella-shaped ...... subg. Asterella sect. Brachvblepharis 4. Spores distally areolate or alveolate but not ridged...... subg. Phragmoblepharis + Spores distally ridged (the ridges sometimes alveolate) ...... 5 5. Par-autoicous or terminal-autoicous; pseudoperianth with median constriction . .. subg. Saccatae + Dioicous; pseudoperianth without median constriction ...... 6 6. Ventral sca le appendages 2-4; involucre deeply cleft; spores yellow ...... subg. Wallichianae sect. Ca lijornicae + Ventral scale appendages 1(- 2); invo lucre entire; spores brown or red-brown ...... subg. Wallichianae sect. Wallichianae

Asterella subgenus Saccatae (Grolle) D.G. Long, Journal of Bryology 22: 13,2000. Thalli xeromorphic, without strong smell; vegetative branches terminal and with ven­ tral innovations; assimilation tissue with a single layer of air chambers or with 'spongy tis­ sue' below; ventral scale appendages I or 2 per scale, lanceolate, not constricted, entire or toothed. Sexual condition par-autoicous or terminal-autoicous; androecia aggregated in cush­ ions; carpocephalum tall-hemispheric or rounded-conical; shortly-lobed or almost unlobed; involu cre with free margin with median cleft; pseudoperianth laterally compressed when young, transversely constricted, lobes united at apex, divided approximately to half-way. Capsule lid fragmenting irregularly; spores yellow-brown or black, with ridged orna­ mentation similar on proximal and distal surfaces, trilete, with distinct proximal pole; elaters 2-spiral. Type: Astere//a saccata (Wahlenb.) A.Evans

Constituent species and distribution: Asterella alpina (Steph.) D.G.Long: S. America (Bolivia). Asterella grollei D.G.Long: E. Asia (China, Nepal). Asterella muscicola (Steph.) S.W.Arnell: Africa (southern Africa). Asterella palmeri (Austin) Underw.: N. & c. America (California, Mexico). Asterella pringlei Underw.: C. & S. America (Mexico, Guatemala, Colombia). Asterella rugosa A.Evans: S. America (Mexico). Asterella saccata (Wahlenb.) A.Evans: Europe, Asia, N. America. D. G. LONG: Studies on the genus Asterella (Aytoniaceae) VI 257

Asterella subgenus Wallichianae D.G. Long, Lindbergia 26: 43, 2001. Thalli xeromorphic or somewhat hygromorphic, aromatic; vegetative branches mostly terminal with occasional ventral innovations; assimilation tissue of an upper layer of tall broad air chambers and a lower layer of spongy tissue; ventral scale appendages 1(- 2) or 2--4, lanceolate to broadly ovate, acute to obtuse, constricted at base or not, margin entire or weakly toothed. Sexual condition dioicous; androecia forming cushions; carpocephalum broadly hemispheric, shallowly lobed; involucre with free margin entire or deeply cleft; pseudope­ rianth not compressed or constricted, lobes united at apex, divided to middle. Capsule lid fragmenting irregularly; spores brown to red-brown or yellow, coarsely ridged on both surfaces, trilete with conspicuous proximal pole; elaters l- 2-spiral. Type: Asterella wallichiana (Lehm. & Lindenb.) Pande et at. ex Grolle

Asterella subgenus Wallichianae section Wallichianae Characters as for subgenus but with ventral scales with 1- 2 appendages, undivided in­ volucre, spores brown or red-brown with ridges finely striate or papillose. Type: Asterella wallichiana (Lehm. & Lindenb.) Pan de et at. ex Grolle

Constituent species and distribution : Asterella wallichiana (Lehm. & Lindenb.) Pande et at. ex Grolle: E. and S.E. Asia, Oceania (Solomon Islands).

Asterella subgenus Wallichianae section Californicae D.G. Long sect. novo A sect. Wallichianis squamis ventralibus 2--4 appendiculis gerentibus, involucro mar­ gine profunde fisso, sporis flavis porcis alveolatis praeditis distinguenda. Characters as for subgenus but ventral scales with 2--4 appendages, involucre deeply cleft; spores yellow with ridges alveolate. Typ e: Asterella californica (Hampe) Underw.

Constituent species and distribution: Asterella californica (Hampe) Underw. : N. & C. America (Arizona, California, Mexico). Asterella californica is a distinctive species whose relationships are not clear, and further investigation is needed. It is placed in subg. Wallichianae on account of its dioicous sexual condition and ridged spores, but it differs significantly from A. wallichiana in many re­ spects and may prove to be worthy of subgeneric rank.

Asterella subgenus Asterella Thalli hygromorphic, sometimes with seasonal xeroshoots, usually strongly aromatic; vegetative branches terminal and ventral; assimilation tissue of one to several layers of spreading, overlapping air chambers; ventral scale appendages single, rarely two, oblong to lanceolate, rarely ovate, acute to obtuse, constricted or not at base, margins entire, rarely toothed. Sexual condition par-autoicous, ventral-autoicous or terminal-autoicous; androecia of scattered ostioles or weakly cushion-forming; carpocephalum hemispheric to almost flat, 258 1. Hattori Bot. Lab. No. 97 2 0 0 5 rarely conical, lobes shallow to deep; involucre with free margin entire or cleft; pseudope­ rianth not compressed or constricted, lobes free at apex, divided approximately to half. Capsule lid fragmenting irregularly; spores yellow or orange-yellow, regularly areo­ late distally, proximally dissimilar, trilete, with distinct proximal pole; elaters 2- or 3-spiral. Type: Asterella tenella (L.) PBeauv.

Asterella subgenus Asterella section Asterella Characters as for subgenus but with carpocephalum hemispheric when mature. Type: Asterella tenella (L.) P.Beauv.

Constituent species and distribution: Asterella tenella (L.) PBeauv.: eastern N. America (Canada, U.S.A.). As discussed above and in Table 5, A. tenella is now considered to be unrelated to A gracilis but shows many features in common with the old subg. Brachyblepharis and ac­ cordingly these have been merged into a larger subg. Asterella.

Asterella section Brachyblepharis (Gottsche et al.) D.G.Long, Journal of Bryology 22: 113, 2000. Characters as for subgenus, but with carpocephalum flat or umbrella-shaped, not hemispheric when mature. Type: Asterella leptophylla (Mont.) Pande et al. ex Grolle

Constituent ~pecies and distribution: Asterella abyssinica (Gottsche) Grolle: Africa (tropical and southern Africa). Asterella africana (Mont.) A.Evans. : S. Europe, Macaronesia, Africa. Asterella blumeana (Nees) Kachroo: Asia (Indonesia). Asterella chilensis (Nees & Mont.) A.Evans: S. America (Chile, Argentina). Asterella cruciata (Steph.) Horik.: E. Asia (Japan, Korea, China). Asterella dissoluta (Steph.) Grolle: E. Africa. Asterella dominicensis S.W.Arnell: C. & S. America. Asterella khasyana (Griff.) Pande, K.PSrivast. & Sultan Khan: SE. Asia, tropical Africa. Asterella leptophylla (Mont.) Pande et al. ex Grolle: E. and SE. Asia. Asterella limbata D.G. Long & Grolle: SE. Asia (Indonesia, Malaysia). Asterella shimizuana H.Inoue: SE. Asia (Papua New Guinea). Asterella tenera (Mitt.) R.M.Schust. : Australia, Tasmania, New Zealand. Asterella venosa (Lehm. & Lindenb.) A.Evans: C. & S. America.

Asterella subgenus Phragmoblepharis Grolle, Feddes Repertorium 87: 246, 1976. Thalli xeromorphic, aromatic or not; vegetative branches mostly terminal or mostly ventral; assimilation tissue of 1(- 3) layers of narrow vertical or irregular spongy air cham­ bers, with or without lower spongy layer; ventral scale appendages 1- 2 (- 3), linear, lanceo­ late or ovate, constricted or not at base, apex acute or obtuse, margin entire. Sexual condition par-autoicous or ventral-autoicous; androecia cushion-like; car­ pocephalum hemispheric, shortly to deeply lobed; involucre with free margin entire, sinu- D. G. LONG: Studies on the genus Asterella (Aytoniaceae) VI 259 ate-lobed, emarginate or deeply cleft; pseudoperianth not flattened or constricted, lobes united at apex, divided approximately to half. Capsule lid fragmenting irregularly; spores dark brown, red-brown or yellow, with regularly and completely areolate or alveolate ornamentation similar on proximal and distal surfaces, trilete, with distinct proximal pole; elaters (1-)2-spiral. Type: Asterella elegans (Spreng.) Trevis.

Constituent species and distribution: NB: some Australian species may prove to be synonyms when revised. Asterella australis (Hook.f. & Taylor) Verd.: New Zealand Asterella bachmannii (Steph.) S.WArnell: southern Africa (S. Africa to Malawi). Asterella bolanderi (Austin) Underw.: N. America (California). Asterella conocephala (Steph.) R.M.Schust. : Australia, Tasmania. Asterella echinella (Gottsche) Underw.: N. & C. America. Asterella drummondii (Taylor) R.M.Schust. ex D.G.Long: Australia, New Zealand. Asterella elegans (Spreng.) Trevis.: C. America (W Indies). Asterella heterojiora (Steph.) H.A.Mill. : Oceania (New Caledonia). Asterella innovans (Austin) H.A.Mill.: Oceania (Hawaii). Asterella lateralis M.Howe: C. & S. America (Mexico to Ecuador). Asterella lindenbergiana (Corda ex Nees) Arnell: Europe, N. America. Asterella linearis (Steph.) M.Howe: tropical Africa. Asterella longebarbata (Steph.) H.A.Mill.: Australia. Asterella macropoda (Spruce) A.Evans: C. & S. America (Andes). Asterella marginata (Nees) S.WArnell: S. Africa. Asterella multiflora (Steph.) Pan de et al. ex Kachroo: E. Asia (Himalaya, China). Asterella mussuriensis (Kashyap) Verd.: E. Asia (Himalaya, China, Japan). Asterella pappii (Gola) Grolle: Africa (Ethiopia), SW Asia (Socotra). Asterella persica (Steph.) M.Howe: SW Asia (iran, Arabia). Asterella syngenesica (Bory) Grolle: E. African Islands. Asterella versicolor A.Evans: C. America (Mexico, Costa Rica, Panama). Asterella vulcanica (Schiffn.) Pande et al. ex Kachroo & Bapna: SE. Asia (Indonesia, Papua New Guinea). Asterella whiteleggeana (Steph.) R.M.Schust.: Australia. Asterella wilmsii (Steph.) S.WArneIl: southern Africa (S. Africa to Angola and Malawi).

Subg. Phragmoblepharis is the largest subgenus, and may in future be subdivided into two sections based primarily on spore colour (the largely Australasian group of species in­ cluding A. vulcanica and A. drummondii have yellow spores whereas the others have dark brown or dark purple spores). Grolle (1976) split this subgenus into four sections (Table 3), sect. Phragmoblepharis, Sect. Pappiae Grolle, sect. Lindenbergianae GroIle and sect. Sac­ catae GroUe. Apart from sect. Saccatae which is now elevated to subg. Saccatae, the other three sections all have dark brown spores and are considered here not to constitute different sections. However, further research is needed on this subgenus, a vital precursor of which 260 J. Hattori Bot. Lab. No. 97 200 5 is a revision of Australasian Asterella species.

Asterella subgenus Graciles D.G. Long, lournal ofBryology 22: 113,2000. Thalli xeromorphic, not aromatic; vegetative branches mostly terminal dichotomies, occasionally ventral; assimilation tissue of a single layer of tall air chambers; ventral scale appendages 1- 2, lanceolate to oblong, not constricted at base, apex acute to obtuse, mar­ gins weakly toothed. Sexual condition par-autoicous; androecia ill-defined, of scattered ostioles; car­ pocephalum hemsipheric, shallowly lobed; involucre with free margin deeply cleft; pseudoperianth not flattened or constricted, lobes free at apex, divided almost to base. Capsule lid disc-like, not fragmenting; spores yellow, with irregularly and incomplete­ ly areolate ornamentation on distal surface, proximal surface with similar ornamentation, but lacking trilete ridges and proximal pole (alete); elaters 3-spiral. Type: Asterella gracilis (F. Weber) Underw.

Constituent species and distribution: Asterella gracilis (FWeber) Underw.: Europe, Asia, N . America. A. gracilis, as discussed above and shown in Table S, is now considered to constitute a subgenus of its own.

CONCLUSIONS The new classification presented above will require further refinement in future, par­ ticularly when African and Australasian species have been revised, and when more compre­ hensive molecular data become available. The only one of Grolle's three subgenera which remains unchanged is Subgenus Phragmoblepharis, the largest. Both subg. Saccatae and subg. Phragmonblepharis may require further subdivision as the spores within the sub­ genus are quite diverse.

ACKNOWLEDGM EN TS Thanks to: Riclef Grolle (Jena), Helene Bischler (Paris), Daniela Schill (Edinburgh), Lawrie Springate (Edinburgh) and Sally Rae (Edinburgh).

REFERENCES Bischler, H. 1998. Systematics and evolution of the genera of the Marchantiales. Bryophytorum Bib­ liotheca 51: 1- 20 I. Gottsche, K. M., J. B. G. Lindenberg & c. G. Nees von Esenbeck. 1844- 1847. Synopsis Hepati­ carum. Hamburg, Meissner. Grolle, R. 1976. Verzeichnis der Lebermoose Europas und benachbarter Gebiete. Feddes Repertori­ urn 87: 171 -279. Grolle, R. 1989. Uber Asterella subg. Brachyblepharis in Lateinamerika. Wissenschaftliche Zeitschrift der Friedrich-Schiller-Universitiit Jena, Naturwissenschaftliche Reihe 38: 231 - 239. Grolle, R. & D. G. Long. 2000. An annotated check-list of the Hepaticae and Anthocerotae of Europe and Macaronesia. Journal of Bryology 22: 103- 140. Long, D. G. 1998. Spore colour and ornamentation in the of Asterella (Marchantiales, Ay- D. G. LONG: Studies on the genus Asrerella (Aytoniaceae) VI 261

toniaceae). In: J. W. Bates, N. W. Ashton & J. G. Duckett (eds.) Bryology for the Twenty-first Century: 99~112. Leeds, Maney. Long, D. G. 1999. Studies on the genus Asterella. IV Asterella grollei sp. nov., a new species from Eastern Asia related to the American A. paimeri. The Bryologist I 02: 169~ 178. Long, D. G. 2000. Revision of the liverwort genus Asterella P.Beauv. (Marchantiales, Aytoniaceae) in continental Eurasia, Malesia and Japan. PhD thesis. Dublin, Trinity College. Long, D. G. (in prep.). Revision of Asterella in Eurasia. Long, D. G. (in press). Asterella . In : H. Bischler-Causse, S. R. Gradstein, S. Jovet-Ast, D. G. Long & N. Salazar Alien, Flora Neotropica Monograph 20. The Marchantiidae. Long, D. G., M. Moeller & J. Preston. 2000. Phylogenetic relationships of Asterella (Aytoniaceae, Hepaticae) inferred from cpDNA sequences. The Bryologist 103: 625 ~644. Schuster, R.M. 1992. The Hepaticae and Anthocerotae of North America. Vol. 6. Chicago, Field Mu­ seum of Natural History. Stephani, F. 1898~ 1900. Species Hepaticarum. Vol. I. Geneva, Basel & Lyon, Herbier Boissier. Stephani, F. 1917~ 1925. Species Hepaticarum. VOI. 6. Geneva, Basel & Lyon, Herbier Boissier.