BFNA Title: Herbertaceae
Herbertus – Herbertaceae
XX. HERBERTACEAE Müller Frib. ex Fulford & Hatcher
W. B. Schofield
Plants pendent or forming thick wefts; branches from axils of underleaves and sometimes also those of leaves; often with ventral flagella. Leaves alternate, incubous, concave, deeply 2-lobed, with a few teeth near base, lobes entire; underleaves similar to leaves, deeply 2(--3)-lobed. Rhizoids on base of underleaf. Specialized asexual reproduction absent. Gynoecium terminal on an ordinary leafy branch. Perianth often with subfloral branches, well developed, strongly plicate, its mouth deeply lobed, perigynium absent.
Genera 2 (1 in flora): circumtropical: North America, South America, Europe, Asia, Africa, Australia, Pacific Islands.
The Herbertaceae is predominantly epiphytic, but is also found on soil and cliffs. The family extends northward to Arctic and subarctic regions and southward to subantarctic regions, in elevations from near sea-level to above 3000 m. Plants of Herbertaceae are usually robust and rigid, 1--25 cm in secondary branch system in which branches are occasionally lateral, but mainly postical from underleaves. The leaves may be nearly transverse, asymmetrically to symmetrically 2- or 3-lobed, lobes narrowly lanceolate to broadly triangular, usually deeply divided; underleaves symmetrical and transversely attached. Sexual condition is dioicous; androecia are terminal initially but subterminal with growth of androecial shoot, antheridia occur in axils of both lateral and underleaves; the perianth is terminal, oblong-fusiform, 3--6 plicate, its apex divided into 6--9 lobes.
SELECTED REFERENCES: Evans. A. W. 1917. Notes on the genus Herberta, with a revision of the species known from Europe, Canada and the United States. Bull. Torrey Bot. Club 44: 191--222. Feldberg, K, H. Groth, R. Wilson, A. Schäfer-Verwimp and J. Heinrichs. 2004. Cryptic speciation in Herbertus (Herbertaceae, Jungermanniopsida): Range and morphology of H. sendtneri inferred from nrITS sequences. Plant Syst. Evol. 249: 247--261. Hodgetts, N. G. 2003. Some synonyms of Herbertus dicranus (Taylor ex Gottsche et al.) Trevls. J. Bryol. 25: 138--140. Hong W. S., B. Deffinbaugh, and B. Sparrow. 1993. The genus Herbertus in western North America. Lindbergia. 18: 41--45. Schuster, R. M. 1957. Notes on nearatic Hepaticae XV. Herberta. Rev. Bryol. Lichénol. 26: 123--145.
1. HERBERTUS Gray, Natur. Arrang. Brit. Pl. 1: 705. 1821 * [For G. Herbert a patron of Pier’Antonio Micheli, 1679--1737]
Plants beginning as a rhizomatous irregularly branched system with rhizoids arising mainly from underleaves, with leaves lacking well-defined vitta, this system disappearing into the persistent secondary system in which the plants are small to robust, rusty to reddish brown, 2--25 cm, suberect to pendulous, forming moss-like turfs or rounded cushions of sparsely irregularly branched stems, postical flagelliferous branches occasional to frequent. Stems rigid to soft, often brittle. Leaves in 3 rows, the ventral smaller than the two lateral, equally to somewhat unequally 2-fid, usually with apparent forked vitta, imbricate to somewhat postically secund and falcate or straight; base of leaf sometimes auriculate; trigones large, sometimes nearly confluent; rhizoids mainly confined to rhizomatous stems that precede the appearance of main shoots, occasionally at the bases of underleaves; oil bodies 4--15+, homogeneous. Specialized asexual structures absent, some plant parts fragile. Sexual condition dioicous; archegonia surrounded by a catkin-like plicate perianth with laciniate mouth on short lateral branches when mature. Sporophyte barely emergent from perianth; sporangium subspherical, with 4--7 stratose wall, dividing regularly into 4 valves or irregularly. Spores spherical.
Species ca. 30 (3 in flora): nearly worldwide, circumtropical, also interruptedly circumtemperate in both the northern and southern hemisphere, extending to low Arctic and low Antarctic, also islands in the Atlantic and the Pacific.
The key to species is based on presence of persistent secondary branches.
1. Lateral leaves deeply 2-lobed to 2/3 leaf length, with lobes narrowly lanceolate, leaf not strongly bulging at base . . . 1. Herbertus aduncus
1. Lateral leaves 2-lobed 1/3--1/2 leaf length, with lobes broadly triangular to broadly lanceolate, leaf strongly bulging at base, especially on antical side.
2. Leaves nearly as broad as long, 2-lobed 1/3 or less leaf length; lobes broadly triangular, decidedly asymmetric . . . Herbertus sendtneri
2. Leaves 2 times as long as broad, 2-lobed 1/2 leaf length, base often bulging outward, lobes lanceolate, symmetric or asymmetric . . . Herbertus dicranus
1. Herbertus aduncus (Dickson) Gray, Nat. Arr. Brit. Pl. 1: 705. 1821
Jungermannia adunca Dickson, Plant. Crypt. Fasc. 3: 12, plate 8, fig. 8. 1793
Plants brownish to red-brown, sometimes dark green or wine-red, in polsters or turfs. Stems erect to reclining, sometimes unbranched or irregularly few-branched, but sometimes with numerous flagelliferous postical branches, main stems 1--10 cm. Leaves deeply asymmetrically or symmetrically 2-lobed with lobes narrow, 4--7 times as long as wide, vitta strong, extending to middle of leaf or beyond, of elongate cells, leaves imbricate to secund postically, occasionally somewhat squarrose. Sexual condition dioicous; androecia intercalary, perigonial leaves less deeply lobed than most leaves, not falcate; gynoecia terminal, with innovations, becoming lateral with continued growth; perianth ovate, narrowed to mouth, divided into 6 lanceolate lobes.
Capsules mature summer, confined to epiphytic populations. Commonly epiphytic, also terrestrial or cliffs; forests and peatland, 0--1000 m; Alta., B.C.; Alaska, Oreg., Wash.
Herbertus aduncus is also found in southeastern Asia (as subsp. schusteri H.A. Miller & G. Scott, and in western Europe (as subsp. hutchinsiae (Gottsche) Schuster, but these subspecies are weakly distinguished, as is subsp. tenuis. Indeed, the literature concerning these variants is extremely confusing, generated by polymorphism. In North America, sporophytes are known only from the west coast, and even then they are confined to epiphytic material and are not frequent except near the open coast. In consequence, clones are probably frequent, and the eastern North American material presumably represents a clone. Isolation modifies color, stature, deepness of lobing and even the abundance of flagelliferous branches.
1. Leaf bases smooth-margined except for sessile slime-papillae. . . 1a. Herbertus aduncus subsp. aduncus
1. Leaf bases frequently with stalked slime papillae or with teeth terminated by a slime papilla . . .1b. Herbertus aduncus subsp. tenuis
1a. Herbertus aduncus subsp. aduncus
Plants commonly rusty brown, slender, 1--13 cm, in tall, forming turfs or cushions. Stems unbranched or few branched, except for postical flagelliferous branches. Lateral leaves erect and nearly symmetric to asymmetric and secund, deeply divided with a narrow V-shaped sinus; vitta forked and apparent, not extending to apices of lobes.
Sporophytes occasional on epiphytic plants, maturing late spring--early summer. Commonly epiphytic, but also terrestrial in peatland, talus slopes, cliffs, mainly near the coast; 0--1000 m; Alta., B.C.; Alaska, Oregon.
Subspecies aduncus is endemic to Pacific North America. It is relatively easy to determine in the field. Terrestrial plants can be confused with H. dicranus, but the latter species usually has bulging auricles and the lobes of lateral leaves are nearly as wide as long with the sinus more U-shaped than V-shaped.
1b. Herbertus aduncus subsp. tenuis (A. Evans) Miller & Scott
Herberta tenuis A. Evans, Bull. Torrey Bot. Club 44: 219. 1917
Plants slender, yellow- to brownish green, rarely vinaceous, forming mats of suberect stems 0.5--4 cm deep, stems unbranched or irregularly and sparingly branched, 0.5 mm in diameter (or less), of somewhat thick-walled cells. Leaves 0.9--1 mm, with narrow but divergent lobes from a V-shaped sinus 2/3--3/4 length of leaf, slightly or not curved, long-acuminate 0.6--0.7 x 0.15--0.17 mm, sometimes with basal teeth and slime papillae; vitta extending well into lobes, but never to apex. Specialized asexual reproduction by brittle leaf lobes.
Sporophytes unknown, only female plants known. Mainly on cliffs, shaded walls and ledges, also epiphytic on tree trunks; low to high elevations (0 m in Nfld. but mainly above 2900 m); Nfld. and Labr. (Nfld.); Ga., N.C., N.J., N.Y., Penn., S.C., Tenn., Va., W.Va.
Subspecies tenuis is endemic to eastern North America and might be confused with occasional specimens of subsp. aduncus from western North America, but tends to be considerably smaller and more slender than that taxon.
2. Herbertus dicranus (Taylor) Trevisan, Mem. Real. Inst. Lombardo Sci. Lett. Class. Sci. Mat. Nat., Sec. 3, 4: 397. 1877
Sendtnera dicrana Taylor, Syn. Hep., 239. 1845; H. sakuraii subsp. arcticus Inoue & Steere
Plants in tall or short, loose or tight turfs of erect to suberect shoots, also as polsters, 1--20 cm, rusty brown to occasionally vinaceous or nearly black. Stems unbranched to irregularly or densely branched, especially with flagelliferous postical branches. Leaves asymmetrically lobed, usually closely imbricate, falcate-secund postically, especially on main shoots, almost transversely inserted, 2--3 times as long as wide, with lobes 1/2 or less of leaf length, broadly lanceolate, leaf base on antical side usually bulging to nearly auriculate, often with marginal downward pointing teeth and slime papillae, vita extending 2/3 length of lobes, cuticle smooth. Specialized asexual reproduction via brittle shoots. Sexual condition diocous.
Sporophytes unknown in North America. Mainly terrestrial or on cliffs in North America but epiphytic elsewhere, in hyperoceanic climates in open coniferous forests, peatland and on cliffs; 0--500 m; B.C.; Alaska, Oreg., Wash.; Asia; Africa (?); Pacific Islands.
Included here as H. dicranus are North American specimens determined as H. himalayanus (Stephani) Herzog, H. sakuraii (Warnstorf) Hattori and H. hawaiiensis H. Miller. Herbertus dicranus shows extreme variability throughout its range, with the material from Arctic Alaska and interior northern B.C. (as H. sakuraii subsp. arcticus) distinctive in its small size, shallowly lobed leaves and alpine restriction. Specimens from peatland and open hyperoceanic forest can be unusually large (to more than 20 cm), form an extensive loose turf, and show considerable flagelliferous branching. Material of open sites is usually little branched, and varies from rusty red-brown to nearly black. The Oregon population (Saddle Mt.) is smaller than most material other than that of Arctic and alpine sites, but intergrades with material elsewhere. Some specimens throughout the range resemble H. stramineus (Dumortier) Trevisan of Europe.
3. Herbertus sendtneri (Nees) A. Evans, Bull. Torrey Bot. Club. 44: 212. 1915
Schisma sendtneri Nees, Naturg. Eur. Leberm. 3: 575. 1838
Plants in loose turfs or as isolated shoots, yellow-green to brown, stems 6--10+ cm, unbranched or with occasional postical flagelliferous branches, leaves crowded. Leaves somewhat postically secund, 1--1.5 mm, broadly ovate with broad lobes and sinus 1/3 or less the leaf length, and the leaves only slightly longer than wide, symmetrically or asymmetrically lobed; underleaves smaller, more shallowly and symmetrically 2-lobed; lobes are wider than long and thus broadly triangular.
Sporophytes unknown. Terrestrial, shaded cliffs, shaded sites in tundra; 10--2000 m; B.C.; Alaska; Europe (Alps); Asia (Himalayas).
Herbertus sendtneri is readily determined in the field in most instances, but there are morphs of both the other species that can resemble it in size and lobation. This species occurs mainly near the coast, and may be alpine or subalpine, but only to 800 m in its southern range, and extending lower to ca. 10 m in the Aleutian Islands. K. H. Feldberg et al. (2004) place material named as H. subdentatus (Stephani) Fulford into H. sendtneri, but state that it is not identical with it. Until this is resolved H. sendtneri is treated as North Temperate in distribution.