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Published In: Phytologia 65: 427. 1989. (Phytologia) Name publication detailView in BotanicusView in Biodiversity Heritage Library

Project Name Data (Last Modified On 10/25/2011)
Acceptance : Accepted
Project data     (Last Modified On 10/25/2011)

75. HILPERTIA                  Plate 112.

Hilpertia Zand., Phytologia 65: 427, 1989. Type: Hilpertia velenovskyi (Schiffn.) Zand.


     Found on soil in Canada (Northwest Territories) and countries of eastern central Europe.


     Corley et al. (1981) suggested that Tortula velenovskyi is probably best placed in a separate section of Tortula. It is here treated, together with T. scotteri, as a separate genus, Hilpertia.

            Schiffner (1893) reviewed the extensive variation in sexuality in the type species. The modification of the upper laminal margins of Hilpertia into tubes of photosynthetic tissue (Pl. 112) is paralleled in species of Pseudocrossidium and to a lesser extent in Tortula revolvens (Pl. 89, f. 4). Hilpertia has many of the features of species of Acaulon including the ovate (rather concave) leaf shape, thin costa, upper laminal cells often hyaline apically and dorsally superficially thick-walled (as easily seen in section, Pl. 112, f. 4–5), a hyaline awn, and red KOH color reaction. The concave leaves may indicate an ancestry of taxa with a somewhat bulbiform habit, thus Hilpertia may well be derived from Acaulon-like ancestors through desuppression of the sporophyte and elaboration of the leaf margins (but cf. Cladograms 13 and 14). Hilpertia is easily distinguished from Acaulon by its revolute leaf margins, elongate stems, elongate setae, and peristomate, cylindrical capsules. On the other hand, the leaves of Stegonia latifolia and S. hyalinotricha (Pl. 69) are quite similar morphologically to those of Hilpertia, thus Hilpertia may have been derived from ancestors shared with Stegonia by development of photosynthetically specialized laminal margins, differentiated perichaetial leaves, and red laminal KOH reaction. Cladistic analysis (see Cladogram 14), contrarily, indicates that Stegonia is best hypothesized as rather distantly related, and that Acaulon does not share immediate ancestors with Hilpertia.

Literature: Boros (1941), Karczmarz (1961), Kuc (1960), Peciar (1960b), Pospísil (1977), Waclawska (1958), Zander (1989), Zander and Steere (1978).
Number of accepted species: 2
Species Examined: Hilpertia scotteri (BUF), H. velenovskyi (FH, NY).


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            Plants growing in loose cushions, greenish brown above, light brown below.  Stems branching irregularly, to 1.0 cm in length, transverse section rounded-pentagonal, central strand distinct, sclerodermis not or weakly differentiated, hyalodermis absent; axillary hairs to 8 cells in length, all hyaline or the basal one yellow-brown; rhizoids rare.  Leaves crowded, larger above, appressed and tightly spiralled when dry, weakly spreading when moist, ovate to circular, 1.3–2.0 µm in length (including awn), upper lamina flat to more usually quite concave, margins strongly revolute (to 2 times), entire or broadly toothed at or near the base of the awn; apex broadly acute, hyaline in an apical patch or triangle; base not differentiated in shape; costa narrow but broader above, excurrent as a hyaline awn, costa with lamina inserted laterally, superficial cells long-rectangular and smooth on both sides, 2–4 rows of cells across costa ventrally at midleaf, costal transverse section rounded, stereid band rounded in shape, ventral epidermis present but dorsally absent, guide cells 2 in 1 layer, hydroid strand present; upper laminal cells hexagonal to short-rectangular or rhomboidal, 14–25 µm in width, 2–4:1, internal walls thin to thickened and porose, dorsal superficial walls much thickened, weakly convex superficially on both sides, cells of leaf apex rhomboidal to fusiform, smooth, cells of revolute margin enlarged, strongly chlorophyllose; papillae absent medially, usually hollow-papillose on revolute margins; basal cells weakly differentiated, rectangular, ca. 16–18 µm in width, 2–3:1, walls thin. Propagula when present (1–)3–4 celled, brown, spherical to elliptical, mostly 30–50 µm in length, borne on basal rhizoids.  Synoicous, paroicous, autoicous or apparently dioicous but probably rhizautoicous. Perichaetia terminal, inner leaves usually differentiated, long-oval, margins usually little differentiated, to 1.7 µm in length, basal portion of leaf sheathing, lower cells rectangular, very thin-walled. Perigonia lateral or occasionally terminal on a separate plant. Seta 3.5–4.0 µm in length, 1 per perichaetium, yellow-brown, twisted counterclockwise above, clockwise below; theca 1.2–1.5 µm in length, yellow-brown, elliptical, occasionally weakly ventricose, exothecial cells ca. 16–23 µm in width, 2–3:1, thin-walled, stomates phaneropore, on capsule neck, annulus of 3 rows of smaller, quadrate, highly vesiculose cells; peristome teeth 32, linear, densely branching-spiculose, 300–700 µm in length, with many articulations, twisted counterclockwise about 1/2 turn, basal membrane short, to 45 µm in height, papillose-spiculose. Operculum broadly short-conic to long-conic, 0.4–1.0 µm in length, cells twisted 1/2 turn counterclockwise.  Cal

yptra cucullate, smooth, ca. 2.8 µm in length. Spores 13–16 µm in diameter, light brown, indistinctly papillose. Laminal KOH color reaction red.

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