BFNA Title: Plicanthus
XX. PLICANTHUS R.M. Schuster, Nova Hedwigia 74: 484. 2002 * [Latin/greek plica fold, anthos flower, alluding to the plicate perianth]
Chandonanthus Mitten in J. D. Hooker, Handb. N. Zeal. Fl. 2: 750. 1867
Plants rather robust, but fragile when dry. Stems in cross section with firm-walled cells throughout; sometimes with paraphyllia. Lateral leaves squarrose and uneven, very deeply and asymmetrically 3-fid; lobes abaxially concave, acuminate, and ± spiny; cells with very coarse trigones and occasionally with intermediate thickenings. Underleaves symmetrically 2-fid and little smaller than lateral leaves. Asexual reproduction lacking. Sexual condition dioicous. Androecia narrower than vegetative parts. Gynoecia: perianth strongly 6- to 8-plicate, mouth not tightly closed and longly ciliate. Sporophytes not observed in the flora.
Species 5 (1 in the flora); North America, Asia, Africa, Indian Ocean Islands, Pacific Islands, Australia.
SELECTED REFERENCES: Schuster, R. M. 2002. Revisionary studies of the Chandonanthoideae (Jungermanniales, Jungermanniaceae). Nova Hedwigia 74: 465--496.
1. Plicanthus hirtellus (F. Weber) R. M. Schuster, Nova Hedwigia 74: 492. 2002
Jungermannia hirtella F. Weber, Hist. Musc. Hep. Prodr. 50. 1815; Chandonanthus hirtellus (F. Weber) Mitten in B. C. Seemann
Plants 30--70(--100) x (0.4--)1.6--2.8(--4) mm, simple or sparingly branched, ascending in loose mats, yellowish green or ocher. Stems mostly 300 μm wide, but from 100 to 400 μm, branching terminal of Frullania type (except for innovations); cells in transverse section firm-walled throughout, gradually increasing in size from epidermis to the center; no paraphyllia seen, sometimes slime papillae in the axils of lateral leaves; rhizoids if any, in loose groups closely below underleaves, hyaline, ca. 11 μm wide. Lateral leaves succubous with oblique insertion, overlapping, hardly different when dry and wet, squarrose and very uneven, irregularly quadrangular in outline, very deeply and asymmetrically 3-fid with the sinuses abaxially protruding, (0.2--)1--1.8(--2) x (0.4--)1.2--2.2(--3) mm, antical base often with a small secondary lobe, this and some basal cilia often ending in slime papillae; lobes unequal, the antical largest, all ± ovate with acuminate apex, abaxially concave, median lobe about 30--40 cells wide at base, margins with many spines of various length, the largest lobe often less spinose; cells somewhat elongated, the subbasal ones (20--)22--38(--41) x (10--)13--20(--22) μm, surface verruculose, cell walls with coarsely nodulose trigones and intermediate thickenings in the longer cells; oil bodies 2--4 per cell, ± spherical, botryoidal. Underleaves tranversely inserted and contiguous, otherwise like the lateral leaves (including the cells), but somewhat smaller, symmetrical, and 2-fid. Specialized asexual reproduction unknown. Sexual condition dioicous. [Androecia intercalary, less wide than vegetative parts (1--1.5 mm), length and number of bracts indefinite, bracts smaller than lateral leaves, saccate, sometimes with paraphyses, bracteoles without antheridia.] Gynoecia terminal on long shoots, innovations usually 1--2; bracts ± 4, free and more crowded than leaves of vegetative parts, similar to these, but somewhat larger and 4-lobed; bracteoles 2, similar to underleaves; fully grown perianths (only young ones seen in North American specimens) exceeding the bracts, 3--4 mm, ± fusiform, some antically curved, 6- to 8-plicate, mouth not tightly closed, somewhat lobed, and with several-celled cilia; ca. 15 archegonia in the perianth. Sporophytes unknown.
Humus under shrubs, cedar forest, dryer places of bogs or rock shelves; mostly with Herbertus sp.; low to moderate elevations; B.C.; Asia, Africa, Indian Ocean Islands, Pacific Islands, Australia.
Plicanthus hirtellus is a rare species in North America confined to westernmost maritime Canada. The few known British Columbia populations are in the most northern stations worldwide.