Arctoa (2001) 10: 189-200 ON THE AXILLARY HAIRS OF LEPTOBRYUM (MEESIACEAE, MUSCI) AND SOME OTHER ACROCARPOUS MOSSES Î ÏÀÇÓØÍÛÕ ÂÎËÎÑÊÀÕ LEPTOBRYUM (MEESIACEAE, MUSCI) È ÍÅÊÎÒÎÐÛÕ ÄÐÓÃÈÕ ÂÅÐÕÎÏËÎÄÍÛÕ ÌÕΠVALERIJ I. ZOLOTOV1 & MICHAEL S. IGNATOV1 ÂÀËÅÐÈÉ È. ÇÎËÎÒÎÂ1 È ÌÈÕÀÈË Ñ. ÈÃÍÀÒÎÂ1 Abstract Axillary hairs of 55 species of genera Amblyodon, Aplodon, Aulacomnium, Brachymitrion, Breutelia, Bryobrittonia, Bryum, Catoscopium, Encalypta, Funaria, Leptobryum, Meesia, Mnium, Orthodontium, Orthotrichum, Paludella, Philonotis, Plagiomnium, Plagiopus, Pohlia, Pyrrobryum, Rhodobryum, Rhizomnium, Splachnum, Tayloria, Tetraplodon, Timmia, Ulota, Voitia, Zygodon are described (and illustrated for most of genera). Axillary hair morphol- ogy is in agreement with the placement of Leptobryum in Meesiaceae, a family close to Splachnaceae. Similarity of axillary hairs in Encalyptaceae and Timmiaceae, as well as in Mnium and Rhizomnium is outlined. Ðåçþìå Ïàçóøíûå âîëîñêè 55 âèäîâ èç ðîäîâ Amblyodon, Aplodon, Aulacomnium, Brachymitrion, Breutelia, Bryobrittonia, Bryum, Catoscopium, Encalypta, Funaria, Leptobryum, Meesia, Mnium, Orthodontium, Orthotrichum, Paludells, Philonotis, Plagiomnium, Plagiopus, Pohlia, Pyrrobryum, Rhodobryum, Rhizomnium, Splachnum, Tayloria, Tetraplodon, Timmia, Ulota, Voitia, Zygodon îïèñàíû (è äëÿ áîëüøèíñòâà ðîäîâ òàêæå ïðîèëëþñòðèðîâàíû). Ñòðîåíèå ïàçóøíûõ âîëîñêîâ ñâèäåòåëüñòâóåò â ïîëüçó ïîìåùåíèÿ Leptobryum â Meesiaceae, êîòîðîå ðàññìàòðèâàåòñÿ êàê ðîäñòâåííîå Splachnaceae. Îòìå÷åíî ñõîäñòâî ïàçóøíûõ âîëîñêîâ Encalyptaceae è Timmiaceae, à òàêæå Mnium è Rhizomnium. Recent advances in the analysis of DNA all regional floras). Molecular data removed Lep- sequence data of mosses brought the evidenc- tobryum from Bryaceae, and put it very definite- es that both morphological and molecular data ly in proximity to Meesiaceae, in a rather isolat- lead to the generally identical classification, ed clade, which includes also Splachnaceae (Hed- at least at the level of families and genera. derson & al., 2000; Cox & al., 2000; Newton & However, some results of sequence analysis al., 2000; Goffinet & Cox, 2000). Buck & Goffi- appeared to be unexpected, contradicting the net (2000) recognized order Splachnales with 3 traditional ideas of the relationships of this families: Splachnaceae, Meesiaceae and Catasco- or that group. Among them the case of Lepto- piaceae (however without explanation of reasons bryum pyriforme (Hedw.) Wils. is probably for the latter family). the most interesting. Despite of a rather small volume, Meesiaceae Leptobryum pyriforme is the type species are very poor in synapomorphic characters, and of the the genus, and the only widespread and comparing its desription (for example, in Crum well-known species of the genus of 2(-6?) spe- & Andreson, 1981) with those of Bryaceae, one cies (Crosby, 1999). This species was invari- would hardly find any formal key character for ably placed in Bryum or Pohlia (Hedwig, 1801, their separation: Meesia and Paludella have rath- and other authors of the first half of XIX er thick-walled leaf cells, but in Amblyodon cells centure), later, after segregation in separate are thin-walled; Meesia and Amblyodon exhibit genus – near Bryum or Pohlia, and then with- the tendency to reduction of exostome and lack in the family Bryaceae (Brotherus, 1924, and of ciliae, but Paludella has rather normal exos- 1 – Main Botanical Garden of Russian Academy of Sciences, Botanicheskaya 4, Moscow 127276 Russia – Ðîññèÿ 127276 Ìîñêâà, Áîòàíè÷åñêàÿ 4, Ãëàâíûé áîòàíè÷åñêèé ñàä Ðîññèéñêîé Àêàäåìèè Íàóê 190 VALERIJ I. ZOLOTOV & MICHAEL S. IGNATOV tome. Leptobryum has rather thin-walled lam- In the last decade, axillary hairs became one inal cells and perfect peristome with 3-4 ap- of a standart items of morphological descrip- pendiculate ciliae. tions (at least in special monographic studies), So, neither peristome, nor leaf (two main but were not specially reviewed throughout sources of morphological characters in many acrocarps. By this reason we added to this study groups of mosses) are useful to evaluate this some related or otherwise nearby placed groups new placement of Leptobryum from the mor- of acrocarps with double peristomes, despite the phological point of view. In this situation all primary aim of this paper was just to point out other characters become more important, even the similarity of axillary hairs in Leptobryum if they are rarely useful at familial level. One of and Meesiaceae. them, the axillary hair' structure, appears to be MATERAL AND METHOD a good support of relation of Leptobryum with Species, number of studied specimens and both Meesiaceae and Splachnaceae. of axillary hairs, and character states of the Axillary hairs were first used in taxonomy latter are given in the Table 1, and illustrated of the generic level by Saito (1975), for classifi- in Figs. 1-67. The color formula of axillary hairs cation in Pottiaceae. Buck (1987) found them (in Table 1) is introduced here for the descrip- useful in familial classification of Hookeriales. tion of color pattern. The deepness of pigmen- One of the biggest overviews (200 species) of tation is evaluated for each cell in 1 to 6 scale axillary hair morphology has been done by He- (1 – hyaline; 2 – very light; 3 – light; 4 – denaes (1990) for northern (mostly European) moderate; 5 – deep; 6 – very deep), from base pleurocarps. Hedenaes concluded that in taxa to top. List of specimens used for this study is he studied the axilary hairs (a) are usually not in the Appendix 1. family-specific; (b) rather homogeneous within RESULTS AND DISCUSSION one genus, and if not so – might be because of 1. The structure of the axillary hairs described unnaturalness of that genus; (c) the fact of sim- for Meesiaceae by Griffin & Buck (1989) is ilarity in axillary hairs does not mean that taxa found also in Leptobryum. Their axillary hairs can not be quite unrelated; (d) some species have are peculiar in two respects: (1) only one upper peculiar axillary hairs highly diagnostic at the cell is hyaline; other cells are colored, and the species level. No one similar overview has been intensity of pigmentation is commonly increas- done for acrocarps. The only family where axil- ing upwards, so the second cell from the top is lary hairs are useful for intrafamilial classifica- the deepest in color; (2) upper cell is large and tion appear to be Bartramiaceae (Griffin, 1991, slightly to moderately inflated, so the axillary 1998; Griffin & Buck, 1989). Discussing Bartra- hair has club-like shape. Both these features are miaceae, Griffin & Buck (1989) overviewed also observed in Leptobryum, Meesia, Amblyodon axillary hairs of Aulacomniaceae, Meesiaceae and and Paludella, at least in some hairs (Figs. 1- Timmiaceae (neighbors of Bartramiaceae in Fleis- 13). Club-like shape is very distinct in Splach- cher-Brotherus' family arrangement). Their com- naceae (Figs. 15-28), and in this family Lepto- parison revealed (1) Bartramiaceae have 3 main bryum-like color pattern (second upper cell hav- types of axillary hairs, well correlated with oth- ing deepest pigmentation) is observed in some er characters of plants and therefore taxonomi- species of Tayloria, Brachymitrion and in Apl- cally useful; (2) Aulacomniaceae have rather odon; in Splachnum, Tetraplodon and Voitia generalized pattern of axillary hairs; (3) axil- this pattern is inapparent. Thus, the placement lary hairs in Meesiaceae are very peculiar in hav- of Leptobryum in Meesiaceae is supported by ing only one very long upper hyaline cell, and axillary hair morphology; Splachnaceae (at least deeply brick-red other cells; this peculiar pat- some genera) also share this pattern of pig- tern allowed to suggest no close relationships mentation of axillary hairs, which support its between Meesiaceae and Bartramiaceae; (4) close to Meesiaceae. Timmiaceae were found very odd in having very Besides these families, club-like axillary hairs long (to 700 μm) filiform axillary hairs, hyaline have been observed in Catascopium (Fig. 14) throughout, a case known in Bartramia (thus and Funaria (Figs. 47-48). Few club-like hairs considered allied with the Timmiaceae). were seen in genera with commonly not club- On the axillary hairs of Leptobryum and some other acrocarpous mosses 191 3 4 2 1 5 6 7 10 8 9 100 μm 14 13 11 12 Figs. 1-14: Axillary hairs of: 1-6 – Leptobryum pyriforme (Hedw.) Wils.; 7-8 – Meesia longiseta Hedw.; 9 – M. muelleri C. Muell. et Hampe; 10 – M. triquetra (Richter) Aongst.; 11-12 – Amblyodon dealbatus (Hedw.) B.S.G.; 13 – Paludella squarrosa (Hedw.)Brid.; 14 – Catascopium nigritum (Hedw.)Brid. like hairs: Rhizomnium (Figs. 42, 44) and Mni- 2. In many groups axillary hairs are rather um (Fig. 46). The distant position of at least “average”, without any sound peculiarities, con- Funariaceae was demonstrated recently in most sisted of 1-2(-3) short colored basal cells and of studies (Newton & al., 2000; Goffinet & Cox, (1-)2-5(-8) longer hyaline cells. This case is 2000; Cox & al., 2000). Therefore, we can just known in most of pleurocarps (cf. Hedenaes, conclude, that the club-like shape alone is not a 1990). In this study it was observed in Bryum, very specific character. Therefore we hesitate to Pohlia, Rhodobryum, Pyrrobryum, Plagiomni- comment the placement of Catoscopiaceae in um, Bartramia, Aulacomnium, Orthotrichum, and proximity to Meesiaceae and Splachnaceae Ulota. This character state is obviously plesio- (Buck & Goffinet, 2000). morphic and can be used pro or contra in tax- 192 VALERIJ I. ZOLOTOV & MICHAEL S. IGNATOV 15 17 16 18 19 20 100 μm 21 22 23 24 25 27 26 28 Figs. 15-28: Axillary hairs of: 15 – Aplodon wormskjoldii (Hornem.) Kindb.; 16 – Brachymitrion moritzianum (C. Muell.) A. Kop.; 17-18 – Tayloria acuminata Hornsch.; 19-20 – T. lingulata (Dicks.)Lindb.; 21 – T. froelichiana (Hedw.) Mitt. ex Broth.; 22 – Splachnum ampullaceum Hedw.; 23-24 – S. luteum Hedw.; 25 – Tetraplodon angustatus (Hedw.) B.S.G.; 26-27 – T. mnioides (Hedw.) B.S.G.; 28 – Voitia nivalis Hornsch. On the axillary hairs of Leptobryum and some other acrocarpous mosses 193 31 29 30 34 38 36 37 32 35 33 40 41 39 44 43 42 100 μm 45 46 Figs.