Joum. Hattori Bot. Lab. No. 62: 281-288 (June 1987) PHAEOCEROS LAEVIS (L.) PROSK. AND P. CAROLINIANUS (MICHX.) PROSK., THEIR SPORES GABRIELA G. HAsSEL DE MENENDEZl ABSTRACT. Descriptions and scanning electron micrographs of the lectotype of Anthoceros lae vis L., the type species of Phaeoceros Prosk., and of the type of A. carolinianus Michx. are presented to illustrate the characteristics which demonstrate that they belong to different species. Photographs of the type specimens are provided, together with details of the spores of "Anthoceros JaWs majoribus Dill ." , which are identical to those of Phaeoceros carolinianus (Michx.) Prosk. I NTRODUCTION In order to promote further studies on the Anthocerotopsida, the author (1984) began a study of the two Linnean species remaining in the class, Anthoceros punctatus L. and A. laevis L., in which the excellent diagnostic characters of the spores were emphasized. In specimens with mature capsules the spores remain indefinitely in herbaria, and can be recognized in sediments, etc. The spores of the first species, the type species of Anthoceros [Mich.] L., were described and illustrated (l.c.). This paper will deal with the second Linnean species, Anthoceros laevis the type species of the genus Phaeoceros Prosk. which together with P. carolinianus (Michx.) Prosk. are the most frequently encountered species of this genus. P. carolinianus is often considered to be a subspecies of the former (Proskauer 1954a, b, 1958), being disting­ uished from it only by its bisexual gametophyte. Proskauer has denied that spore characters have any value in distinguishing the subspecies (1958: 1316), a statement that would be correct if the two type specimens had the same kind of spore. It is the author's intention to show that these taxa are perfectly distinguishable by the ornamentation of their spores, and should not be regarded as subspecies of a single species. HISTORICAL REVIEW When describing Anthoceros iaevis, Linne (1753, 2: 1139) cited five earlier ref­ erences, although he omitted Dillenius' first description (1719: 211) which was "Licl1en parvus, capitulis hypnoides clavatis" from "Gissa" (Giessen, German Federal Republic). Linne listed 1) "Lichen hepaticus, pediculis gramineis" Buxbaum (1728: 40, tab. LXI, fig. I n, b), from around ditches and springs in Bizant and the Orient, the illustra­ tion representing an anthocerote; 2) "Anthoceros major" Micheli (1729: 11, tab. 7, 1 Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Avda. Angel Gallardo 470, 1405 Buenos Aires, Argentina. 282 Journ. Hattori Bot. Lab. No. 62 1 9 8 7 fig. I), which presumably refers to the same species, found in the gardens of the town of Boboli, in field ditches and near the castle Villa Regia, the plate representing uni­ sexual thallii; 3) "Anthoceros" Linne (1738: 477); 4) "Anthoceros" Royen (1740: 507); and 5) "Anthoceros foliis mayoribus minus laciniatis" Dillenius (1742: 476, tab. LXVIII, fig. 2A & B). Thus in nomenclatural terms Anthoceros laevis L. is based on syntypes. As will be explained later, only the specimens corresponding to 2) and 5) are extant in herbaria. Linne's "Species Plantarum" (1753, 2: 1139) represents the starting point for the nomenclature of the Anthocerotopsida; in it he described A. laevis as "Anthoceros frondibus indivisis sinuatis laevibus", a diagnostic description of the thallus, besides indicating that the habitat of the species is Europe and America boreali. Proskauer (1951: 247) separated from the genus Anthoceros species with thalli lacking mucilage cavities, antheridia in which the wall cells are not organized in de­ finite rows, and yellow spores. For these he established a new genus Phaeoceros Prosk. and designated A. laevis L. as the type species. A few years later (1958: 1316) he chose as the lectotype, the plant referred to as "Anthoceros major" [Micheli 1729]. He stated (1958: 1315) that it was doubtful that Linne had a specimen of A. laevis in his herbarium in 1753, and that the plant of the "Hortus cliffortianus" could not be fo und (confirmed by Dr. A. Harrington 1986 pers. comm.). The plant on sheet no 1272 n. 2, in his herba­ rium could have been present, or sent by Schreber, but is very undesirable for selection as the lectotype since it lacks locality indication, Proskauer's lectotypyfication is not perfect, as indicated by Isoviita (1970 : 10, 16) and Grolle (1976: 217), who had doubts about the existence of Micheli's plant. From Proskauer's notes, "die von Linne zitierte Pflanze Micheli's uber die jeder Zweifel erhaben ist," it is not possible to tell whether he lectotipified on the basis of a specimen or Micheli's drawing. It was essential for the present author to confirm the existence of a type specimen, and to examine the spores of Micheli's original specimen, since drawings alone are quite insufficient for a present-day understanding of the Anthocerotopsida. Fortunate­ ly the pre-Linnean type specimen does exist in Micheli's herbarium in Firenze (Fl fig. I), as confirmed by the author in July 1985. Sheet "Anthoceros" 3355 (?3255) of Micheli's herbarium (a folder of yellowish paper with a pink reinforced back) contains a folded sheet to which is pinned a piece of paper, 7.5 x 10 cm. Stuck to this are two anthocerote plants, each with five sporo­ phytes. There is also an envelope containing four plants, each with two or three sporo­ phytes. All sporophytes are papyraceous and contain yellow spores. "Anthoceros punct." is written in pencil on the piece of paper to which the two plants are stuck whilst "Anthoceros punctatus" is written in another old hand on the back of the folded sheet ; there is no other labelling. These labels undoubtedly more recent, confuse the identity of the plants to which they refer. The specimens should be regarded as the "Iectotype" of Phaeoceros laevis (L.) Prosk. and should not have been labelled Anthoceros punctatus. Proskauer's choice (1958) was correct, since the only other extant specimen in Dillenius's herbarium comes from Virginia (U.S.A.). G. G. HASSEL DE MENENDEZ: Phaeoceros laevis and P. carolinianus spores 283 In his work "Historia muscorum ... " (1742) Dillenius described once again the plant from "Gissa" (corresponding to his fig. A) but added another plant from Virgi­ nia, sent to him by 1. Mitchell (indicated as 2B on the same plate). Dillenius mentions in his description that he did not notice "thecae" at the base, but that these were certain­ ly present on the specimen from Virginia. If "thecae" are the antheridial chambers, one can assume that this was a monoecious specimen. D illenius's herbarium at Oxford (U.K.) contains only the specimen from Virginia (see Hassei de Menendez 1984, lam. 1 right upper corner). A portion of this specimen is housed at H-SOL (lsoviita 1970: 16) (Fig. 3). Its spores are identical to those of "Anthoceros carolinianus", which Michaux (1803, 2: 280) described from a specimen from Carolina Inf., North America (fig. 2). It was S. O. Lindberg (1883: 37), in his revision of Dillenius' herbarium, who indicated that fig. B of Anthoceros JoWs majoribus" (1742, pI. LXVIII) represents A. laevis var. carolinianus (Michx.) Lindbg. and that figure A on the same plate, corresponds to A. laevis (specimen not extant), thereby originating the infraspecific status of "A. caro­ linianus" . DESCRIPTIONS OF THE SPORES AND PSEUDOELA TERS 1) Phaeoceros laevis (L.) Prosk., Bull. Torrey Bot. Club 78: 347, 1951 = Anthoceros major Mich., Nova Genera 11, tab. 7 fig. I (1729), A. laevis L., Spec. Plant. 2: 1139, 1753 p.p. basionym; P. laevis subsp. laevis. (fig. 1). Spores yellow green, 33- 38 flm diam., distal surface with conic slightly curved spines, 1- 1,5 flm high, distributed irregularly up to the border, 11 - 13 spines across the diam., re­ maining surface smooth; equatorial rim (in transmitted light) 2- 3 mm wide; proximal surface with trilete mark (Iaesura) lower than the approximate verrucae of the margo, each verruca ca. 0.5-1 .urn high and wide; triangular areas covered with nearly round verrucae of ± 1 .urn diam., closer together than the distal spines, the intervening surface with low interwoven ornamentation. (With OM at x 600, distal spines visible, even around the border when seen in proximal view; triangular areas nearly flat, verrucae clearly distinguishable, trilete mark lower than margo verrucae). Pseudoelaters pale brown, transparent, simple or formed from 2- 3 adherent, cylindric, thin walled straight to curved cells, each 42-82 .urn long, 5-8.um in diam. Specimens examined: Anthoceros (Hb. Micheli, sheet 3355 or 3255?) (F1), holotype of Anthoceros major Mich ., lectotype of Anthoceros laevis L. fide Prorkauer 1958; Asciano ad radic. Mt. Pisani, Arcangeli 1897-1898 (fI). 2) Phaeoceros carolinianus (Michx.) Prosk., Bull. Torrey Bot. Club. 78 : 347, 1951 = Anthoceros loWs majoribus minus laciniatis Dill., Hist. musc. 476, pI. 68 fig. 2B, 1742; A. laevis L., Spec. Plant. 2: 1139, 1753 p.p.; A. carolinianus Michx., Flora bor.-amer. 2: 280, 1803, basionym; A. laevis var. carolinianus Lindb., Kritisk. Gr. Moss. Dill. Hist. Muse. Helsingsf. 371, 1883; P. laevis subsp. carolinianus (Michx.) Prosk., Rapp. et comm. VIII Congr. Int. Bot. Paris 14--16 : 69, 1954; P . laevis forma carolinianus Schust., Am. MidI. Natural. 49 : 296, 1953 (as fo. "carolinianus (Schweinitz)". (Fig. 2 and 3) Spores pale yellow, 42-47 (49) .urn diam.; distal surface with irregularly placed straight to curved, cylindric, simple or bifurcate at the apex attenuate spines, 2 .urn long in the centre, 0.5 .urn at the border, intervening surface smooth ; 17-21 spines across the diam.; equatorial 284 Journ. Hattori Bot. Lab. No. 62 1 987 FrG. 1. Phaeoceros laevis (L.) Prosk. 1) Detail of lectotype of Anthoceros laevis L. ( = ho)otype of Anthoceros major Micheli, 1729); 2) folder and sheets of the Micheli hepatic and anthocerote herbarium (Fl); 3-4) distal surfaces of spore; 5) detail of distal surface; 6) proximal surface; 7) detail of proximal face, margo and trilete mark to the left; 3-7 from Asciano ad radic Mt.