Ptychanthus striatus (Lehm. & Lindenb.) Nees
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Authority
Thiers, Barbara M. & Gradstein, S. Robbert. 1989. Lejeuneaceae (Hepaticae) of Australia. I. Subfamily Ptychanthoideae. Mem. New York Bot. Gard. 52: 79 p.
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Family
Lejeuneaceae
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Scientific Name
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Description
Species Description - Autoicous; plants to 10 cm long x 2-3 mm wide, dark green to brown in the dried condition, pendent on twigs and branches of trees. Branching Frullania-type, growth habit pinnately compound. Stems approx. 280 µm in diam., in crosssection composed of numerous epidermal cells with thick, brownish walls in 1-3 rows, medullary region of slightly thinner, hyaline cells, 9-13 cells across. Leaves diverging from stem at an angle of approx. 45-60°, contiguous to imbricate, flattened, dorsal lobe broadly ovate, 875-1123 x 600-875 µm, apex acute to apiculate, margins entire or occasionally with a few weak teeth near the apex, acroscopic margin auriculate at dorsal base, slightly overlapping stem, basiscopic margin rounded; marginal cells of dorsal lobe rectangular, 10-15 x 15-23 µm, cells of midportion rhombic, 20-50 x 13-20 µm, cells of leaf base rhombic, 30-50 x 25-30 µm, walls thin, trigones large, cordate, intermediate thickenings present. Lobules basically ovate but very variable, ranging from spherical to rectangular to irregular in outline, 250-300 x 160-200 µm, 1/5-¼ lobe length, inflated basally, keel weakly to strongly rounded, free margin flattened, with 1-3 teeth, all sharply triangular, of 3-4 cells each, sinus between tooth and distal edge of lobule very deep, U-shaped. Underleaves contiguous to imbricate, varying in shape from broadly ovate to spathulate, sides often reflexed, 460-650 x 420-600 µm, 2-3 x stem width, inserted on 6-10 cells, apex rounded to emarginate, irregular to distinctly dentate, margins entire, base auriculate, insertion straight to slightly arched. Gynoecia on short or long branches, innovations usually single, often fertile, bracts erect, bract lobes broadly ligulate, averaging 1100 x 500 µm, apex acute to apiculate, margins entire to irregular or weakly dentate, bract lobules rectangular to ligulate, averaging 350 x 150 µm, apex obtusely to acutely pointed, margins entire; bracteoles rectangular, averaging 800 x 500 µm, apex emarginate, sinus broadly V-shaped, 1/8 bracteole length, lobe apices acute, margins entire. Perianths emergent, elliptical, inflated, averaging 1250 x 700 µm, keels 8-10, extending ¾ perianth length, rounded, not winged, margins entire. Androecia terminal or intercalary on vegetative branches, composed of 5-10 pairs of bracts.
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Discussion
Jungermannia striata Lehm. & Lindenb., Nov. stirp. pug. 4: 16. 1832. Frullania striata (Lehm. & Lindenb.) Mont., Ann. Sci. Nat. Bot. 2:17. 1842. Bryopteris striata (Lehm. & Lindenb.) Mitt, in Seemann, Fl. Vit. 411. 1873. Ptycholejeunea striata Steph., Hedwigia 28: 259. 1889. Type. Nepal. Wallich s.n. & s.d. (holotype, S; isotypes, G, W [3 packets, Herb. Lindenb. #5915, 5918, 5919]). Jungermannia retusa Reinw. et al. var. ß Nees, Enum. pl. crypt. Jav. 39. 1830. Ptychanthus retusus (Reinw. et al.) Nees var. Nees, Syn. Hepat. 292. 1845. Ptycholejeunea retusa (Reinw. et al.) Steph., Hedwigia 28: 258. 1889. Ptychanthus retusus (Reinw. et al.) Steph., Sp. Hepat. 4: 743. 1912. Ptychanthus striatus var. retusus (Reinw. et al.) Verd., Ann. Bryol. Suppl. 4: 122. 1934. Type. Java. Blume s.n. & s.d. (holotype, STR; isotype, W [Herb. Lindenb. #5926]). The original description of Jungermannia retusa by Reinwardt et al. (1824) refers to a species of Thy-sananthus, later named T. planus by Sande Lacoste. Later (1830) Nees designated this plant as var. a. However, in the treatment of Ptychanthus retusus in Synopsis Hepaticarum, Gottsche et al. (1845) implied that var. ß rather than var. a was the type of the species. Presumably this is the source of the subsequent misinterpretation of Jungermannia retusa. Variety ß is clearly referable to P. striatus, and segregation from the typical variety, as suggested by Verdoom (1934), seems unwarranted. On cursory examination, P. striatus might be confused with Spruceanthus thozetianus, Thysananthus fruticosus, or T. spathulistipus, all of which are relatively large plants with a tendency toward forming festoons or projecting shoots. Ptychanthus striatus can be distinguished from all of these species by the absence of Lejeunea-type branches. Ptychanthus striatus is widely distributed in the paleotropics. Verdoom (1934a) recognized three varieties of Ptychanthus striatus: var. perrottetii (Steph.) Verd., var. retusus (Reinw. et al.) Verd. (=var. striatus), and var. intermedius (Spruce) Verd. The Australian plants are closest to var. intermedius, although this variety has somewhat less distinct marginal teeth on the lobule, and the underleaves are more distinctly spathulate and toothed at the apex than in the Australian plants. According to Verdoom, var. intermedius occurs mainly in Australasia and the Pacific. In New Zealand, Ptychanthus has apparently been collected only once, in the 19th century (Wellington, Stephenson s.n., NY). This plant was described by Mitten as Lejeunea stephen-soniana, and transferred to Ptychanthus by Stephani (1912). The species was reduced to synonymy by Verdoom (1934a) under P. striatus var. intermedius. However, we have examined the type specimen of Lejeunea stephensoniana in the Mitten herbarium and find that the plant can be readily separated from P. striatus var. intermedius, as reflected in the following key: 1. Underleaves 2-3 x stem width, with straight or slightly curved insertion line and auriculate base. P. striatus var. intermedius. 1. Underleaves 5-6 x stem width, with deeply arched insertion line and decurrent base. P. stephensonianus. Because of these differences in underleaf features, we are tentatively retaining Ptychanthus stephensonianus (Mitt.) Steph. as a separate species; further work on the infraspecific variation of P. striatus is needed to determine the correct status of this species, and to delimit the varieties of Ptychanthus striatus.
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Distribution
Distribution. Originally reported from Australia by Bailey (1888, 1913, as Ptychanthus squarrosus, a synonym of P. striatus), and later by Mizutani (1977), P. striatus is common in several dense rain forest areas in northern Queensland. This species forms large festoons from the trunks and small branches of trees, especially in very wet areas.
Australia Oceania|