Solenostoma

Váňa, Jiří, Söderström, Lars, Hagborg, Anders & Konrat, Matt Von, 2013, Notes on Early Land Plants Today. 44. Comments on sexuality in Solenostoma (Solenostomataceae, Marchantiophyta) and on some newly described taxa, Phytotaxa 152 (1), pp. 33-47 : 33-37

sexuality in Solenostoma

Bakalin (2013: 139) re-established Jungermannia marcescens Mitten (1861: 91) as a good species, Solenostoma marcescens (Mitt.) Bakalin (2013: 139) , which Váňa (1973: 68) placed in synonymy of Solenostoma sanguinolentum ( Griffith 1849: 302) Stephani (1901: 489) . The experience with relatively copious material by the senior author allows the following comments on the proposed differences between Solenostoma sanguinolentum and Solenostoma marcescens .

Sexuality of plants:—According to the literature information, Jungermannia marcescens is described as “dioica” ( Stephani 1901: 503) or “dioicous?” ( Amakawa 1967: 264). However, Amakawa states “the upper leaves are often ventricose as if they contained antheridia”, but also “male inflorescence unknown”. Solenostoma sanguinolentum is reported as “dioica” ( Stephani 1901: 489) or “dioicous” ( Amakawa 1967: 256). Bakalin (2013: 141) also wrote “Dioicous (? only female organs seen)”. No other information about the sexuality of Solenostoma sanguinolentum or Solenostoma marcescens is known. Váňa (1973: 68) did not give any information about the sexuality of Solenostoma sanguinolentum , only the note that “the type material of Jungermannia marcescens Mitt. is identical in all characteristics with the material of Jungermannia sanguinolenta Griff …”. Váňa & Long (2009: 507) also did not give any information about the sexuality of Solenostoma sanguinolentum , only saying “Androecia (previously unknown in this species) intercalary, bracts 5–7 pairs, relatively remote, slightly saccate at base.” It is of course possible to assume that it can suggest that Solenostoma sanguinolentum (syn. Solenostoma marcescens ) should be dioicous, but that was never explicitly said. Based on the above facts, the senior author was very careful and avoided publishing explicit information about the sexuality of Solenostoma sanguinolentum or Solenostoma marcescen s.

In the years before 1972 (cf. Váňa 1973: 68) and also after 1972 the senior author examined almost all available material of Solenostoma sanguinolentum present in the herbaria BM, E, FH, G, JE, M, NICH, NY, TNS, and W, as well as the material of many recent collections (except some collections made by Chinese bryologists). Lectotypes and many iso(lecto)types of both Solenostoma sanguinolentum (BM – lectotype, FH, G-672, NY - isolectotypes) and Solenostoma marcescens (BM – lectotype, FH, G-14835, NY, Wisolectotypes) were also studied. The material coll. J. Poelt (det. Grolle, M, JE), as well as the collections of Japanese botanists (coll. Z. Iwatsuki, K. Yoda, det. Amakawa, NICH, TNS), the collections of G. and S. Miehe (det. Váňa, MB) and especially the collections of D. Long (det. Váňa, E) contains mostly very good, optimally developed material. Concerning the sexuality, the existence of pure gynoecial shoots with perianths (sometimes with 3–5 ± saccate leaves just below the perianth or sometimes saccate leaves separated by 2–3 not saccate leaves from the perianth), pure androecial shoots (with terminal androecia and also intercalary androecia, terminating by 3–5 pairs of sterile leaves up to the top of the shoot and no trace of archegonia) and one (- three?) paroicous shoot was confirmed.

Gynoecial shoots without saccate leaves below gynoecium were very common, they are present in nearly all specimens examined, as well as in the type specimens of Solenostoma sanguinolentum and Solenostoma marcescens . Gynoecial shoots with saccate leaves below gynoecium were not common, but they were found in the type material of Solenostoma marcescens , and in some other specimens (never in the type specimens of Solenostoma sanguinolentum ). In contrast, pure androecial shoots were very rare. They were never found in the type specimens of Solenostoma sanguinolentum . Neither could Bakalin find the androecia in the isolectotype specimen in NY 967468. Two pure androecial shoots were found in the lectotype specimen of Solenostoma marcescens in BM (Bakalin did not mention pure androecial shoots in the specimen NY 961508), and sometimes found in the specimen coll. Yoda (det. Amakawa as Jungermannia sanguinolenta, TNS 11879), and coll. Long 21570 (det. Váňa as Jungermannia sanguinolenta , E). The issue is complicated by the fact that the leaves are relatively large and only slightly saccate (if at all) at their bases, not characteristically saccate as in many other species of Solenostoma . In the saccate leaves immediately below gynoecia antheridia were never found, only some sterile filaments and primordials of lateral branches were often present. Examination of the saccate leaves somewhat distant from gynoecium resulted in the finding (twice) of some traces which may be interpreted as the rest of antheridial stalk or something like a filament. Well developed antheridia with antheridial stalks were found only once in the course of re-examination of the isotype material of Solenostoma marcescens in BM. One leaf with two relatively well developed antheridia (open) was present. The antheridial stalks were 1-cell wide at the base, and, in part, 2-cells wide above.

Bakalin (at least according the information presented in the article) examined only the isotype specimens of Solenostoma marcescens and of Solenostoma sanguinolenta in NY and there is no information about the study of any additional specimens. He ( Bakalin 2013: 139) found that “the type material of J. marcescens is paroicous, not dioicous as in S. sanguinolentum . Antheridia below the perianth are often lacking in this species, however, and are present in approximately every third shoot. This situation is rather common in the paroicous species of Solenostoma where antheridia are easily washed away when herbarium material is wetted. The paroicous state also suggested by the constant fertilization of the archegonia in the absence of antheridial shoots.” This statement of Bakalin is correct, but he is not the first one showing the described problem.

It should be mentioned that Bakalin, who was the first to discover paroicous inflorescence in the isotype specimen of Solenostoma marcescens , like all previous authors considered Solenostoma sanguinolentum as dioicous (on the basis of examination of the isotype in NY) and on this basis as a separate taxon from Solenostoma marcescens . Unfortunately, it is not possible (at least in the present time by present methods) to confirm the statement by molecular methods because both types were collected in 19 th century.

Taking the above observations of Váňa and of Bakalin into consideration (both considered correct), we have only one species (where the name Solenostoma sanguinolentum has priority), highly proterandrous with heteroicous (not exactly paroicous nor exactly dioicous) inflorescence. The proposed new combination Solenostoma marcescens (Mitt.) Bakalin is superfluous and falls in the synonymy of Solenostoma sanguinolentum . Jungermannia marcescens Mitt. cannot be treated as a “good” species (as already stated by Váňa 1973: 68). Heteroicity is not unknown in the genus Solenostoma and similar genera, but it is not common. It has been reported a few times in Solenostoma paroicum ( Schiffner 1910: 320) Schuster (1953: 402) ( Váňa 1975: 83, Paton 1999: 285), Solenostoma subellipticum ( Heeg 1893: 69) Schuster (1969: 1021) ( Damsholt 2002: 232) , Jungermannia pumila Withering (1796: 866) (cf., e.g., Damsholt 2002: 203, Váňa et Engel 2013: 76), Jungermannia polaris Lindberg (1867: 560) ( Damsholt 2002: 206) , and possibly also in Solenostoma obovatum ( Nees 1833:332) Massalongo (1903: 17) ( Paton 1999: 285) . Also the presence of sterile leaves between perianth and androecium was mentioned e.g. for Jungermannia pumila , Solenostoma paroicum and Solenostoma subellipticum ( Damsholt 2002: 227, 230).

It is also worth mentioning that Bakalin described Nardia geoscyphus ( De Notaris 1859: 486) Lindberg (1874) var. dioica Bakalin et al. (2010: 87) on the basis of different sexuality only. ( N. geoscyphus var. geoscyphus is paroicous). In the footnote on the same page Bakalin correctly presented the published information of Váňa (1976: 379) which in the type plants of Nardia geoscyphoides Amakawa (1957: 167) (described as dioicous) found two subinvolucral bracts on the female inflorescence with antheridial stalks and fragments of an antheridium wall; this species was reduced into synonymy of Nardia geoscyphus . Maybe Nardia geoscyphus var. dioica represents the same problem as was found in the cases of Nardia geoscyphoides and Solenostoma sanguinolentum / marcescens , simply high proterandry.

A probably identical case concerns Lophoziopsis excisa ( Dickson 1793: 11) Konstantinova & Vilnet (2010: 66) and Lophoziopsis propagulifera ( Gottsche 1890: 451) Konstantinova & Vilnet (2010: 67) , discussed in detail in Váňa et Engel (2013: 75–76) where Lophoziopsis excisa is reported as paroicous and Lophoziopsis propagulifera as dioicous ( Stephani 1902: 139), paroicous ( Schuster 1969 a: 521) or dioicous, rarely paroicous or autoicous ( Bakalin 2005: 100). This problem was intensively studied by molecular methods by Vilnet et al. (2007, 2008); and the authors could not resolve Lophoziopsis propagulifera as a distinct species. In that study Lophoziopsis propagulifera (based on a specimen from the Kamchatka region) forms a separate clade with Lophoziopsis excisa (based on collections from the Murmansk area and Spitzbergen). They stated ( Vilnet et al. 2008: 412) that “in view of the quite similar level of sequence divergences within Lophozia excisa , and between Lophozia propagulifera and Lophozia excisa , it is not possible to resolve the taxonomic status of Lophozia propagulifera . If we recognize the latter taxon at the species level, then the Spitzbergen specimens of Lophozia excisa should be treated as separate species, too.” The cladograms in the molecular studies of Vilnet et al. (2007, 2008) reveal that Lophoziopsis propagulifera should be separated at the specific level only if we accept additional “microspecies” within the Lophoziopsis excisa complex and disregard influence of ecological factors on the sexuality of the plants. Maybe similar problems are more common in autoicous species where this phenomenon is more complicated as the autoicity sometimes is difficult to detect because of disintegration of basal parts of the shoots. The many times discussed and not yet fully clarified problem of Lophocolea bidentata / coadunata may be mentioned in this context (cf. also discussion in Váňa et Engel 2013: 41–43).

Perianth:— Bakalin (2013: 139) stated “The perianth in J. marcescens is bistratose in the lower 2/3 of its length, and in S. sanguinolentum only in the lower third” and “The perianth of S. sanguinolentum is much larger than in J. marcescens (up to 6 mm long, vs. to 1.5 mm long)”. In all of about 40 specimens examined by the senior author the perianths were bistratose from 1/4 to 3/4. Young perianths were bistratose only in the lower half whereas mature perianths were bistratose mostly to 2/3–3/4. This character is naturally correlated with the length of the perianth and also with the length of the emergence of perianth from the female bracts. It should be mentioned that the perianths are fully mature in the type of Solenostoma sanguinolentum , which is the source of Bakalin’s observation (and thus bistratose to 2/3–3/4 and 0.7–0.8 emergent), whereas the ones in the type of Solenostoma marcescens are not fully mature (and thus bistratose to 1/3–1/2 and about 0.5 emergent). The maturity of the perianth is the reason no antheridia were found in the type plants of Solenostoma sanguinolentum by any author including Bakalin. Thus, bistratosity and the size of the perianth does not separate Solenostoma sanguinolentum from Solenostoma marcescens .

Colouration:— Bakalin (2013: 139) wrote “The typical coloration of J. marcescens plants is yellowish brownish to brown, as was noted by Mitten (1861), Amakawa (1966) and observed in the study of the first author. In contrast, the typical coloration of S. sanguinolenthum [sic!; in the article Bakalin used both forms: “ sanguinolentum ” and “ sanguinolenthum ”] is light to deep pink. As noted by Váňa (1972 [= 1973]) greencoloured plants of S. sanguinolenthum may occur, but the green coloration can be treated as merely the absence of secondary pigmentation. The presence of brown pigmentation versus pink in the well-exposed phases is quite another matter. Correlated with this feature is the rhizoid coloration; it is colorless to pinkish in S. sanguinolenthum versus brown to golden brown and red-brownish in J. marcescens .”

This information (except “brown”) is the same as presented in Amakawa (1966: 256, 264). It is more precise in Stephani (1901: 489 “superne sanguinea” and 508 “pallide flavo-virens”). Examining a wide spectrum of specimens, it will be found that the colour may be green, yellow-green, yellowish brown, pinkish to in some parts tinged with purplish. Also the type plants of Solenostoma marcescens have partly purplish perianths. The purplish colour is the reaction to the occurrence in sunny places (a similar situation is very well known e.g. in Mylia taylorii ( Hooker 1813: pl. 57) Gray (1821: 693)). The colour of old specimens is mostly pale or yellowish, which probably is caused by the decolouration of green plants after many years. Recent collections (at least the ones examined) are mostly green and tinged with purple.

Rhizoid colouration should, according to Bakalin, be correlated with the colour of plants. The source of this information is probably Stephani (1901: 489, 508), who described rhizoids of Solenostoma sanguinolentum as “pallidis” and of Solenostoma marcescens as “purpureis”. This statement cannot be fully confirmed; golden brown to red brownish rhizoids are also present in some plants of the type of Solenostoma sanguinolenta as well as in many other specimens, and this character is never correlated with the colour of leaves or perianths. Many times rhizoids of the same specimen may be light brown to intensive purple. Thus, “brown” rhizoids and “yellowish brownish to brown” pigmentation can not be used to separate Solenostoma marcescens and Solenostoma sanguinolentum .

Pachydermous leaf cell structure:— Bakalin (2013: 139) stated that “ J. marcescens has rather pachydermous leaf cells, versus leptodermous in S. sanguinolenthum ; this character correlates with the former’s more rigid plant habit than the latter”. This character was also given by Amakawa (1967: 264 “walls slightly thickened”). This character of cells, based on ecology (light), is not constant even in the type plants of Solenostoma marcescens as some plants have cells with thin walls. Bakalin’s drawing (fig. 8: 5) also does not agree with this. Again, a wide spectrum of this character (slightly pachydermous to leptodermous cells) can be found in the examined material. Thus, we conclude that leaf cell structure (leptodermous or pachydermous) is based on the ecological conditions and cannot be used to separate the taxa mentioned.

Bakalin (l.c.: 139) also stated that Solenostoma marcescens resembles species of the Solenostoma pyriflorum Stephani (1917a: 83) group, whereas Solenostoma sanguinolentum is similar to those of the Solenostoma fusiforme ( Stephani 1897: 99) Schuster (1969: 944) group. It is difficult for us to find similarity with Solenostoma pyriflorum or with Solenostoma fusiforme . Unpublished molecular data also confirms that Solenostoma sanguinolentum is very distantly related to Solenostoma pyriflorum and Solenostoma fusiforme .

Conclusions:—Based on the characters discussed above, Bakalin (2013) concluded that Solenostoma marcescens “is a ‘good’ taxon which is rather distant from S. sanguinolenthum ” and makes the necessary combination under Solenostoma . Our observations show no difference between Solenostoma sanguinolentum (if we accept the heteroicous inflorescence for the taxon) and Solenostoma marcescens on the morphological basis as the facts discussed above confirm the opinion presented in Váňa (1973: 68) and Váňa et Long (2009: 507) treating the taxa as conspecific. Until population studies based on molecular methods are at hand, there is no reason to keep the two taxa apart.