Asterella marginata (Nees) S.W. Arnell
  • Hepat. S. Africa


Cite taxon page as 'WFO (2020): Asterella marginata (Nees) S.W. Arnell. Published on the Internet;http://www.worldfloraonline.org/taxon/wfo-0001199000. Accessed on: 06 Jul 2020'

Morphology

Thalli medium-sized, in crowded mats; bright green, firm and compact, hardly areolate, air pores slightly raised, scattered, margins with narrow to wide black border, occasionally reddish purple, very wavy to almost frilly; when dry, thallus margins raised to inrolled. Branches simple or once, rarely twice pseudodichotomously furcate, sometimes with apical or ventrolateral innovations, obovate to obcordate or ligulate, frequently widening rapidly from narrow base, up to 23 mm long, 2.3-5.0 mm wide, 550-565 µm thick medianly, in section 4-9 times wider than thick, apex notched, tips of ventral scales recurved over edge; groove absent, thallus dorsally flattish to somewhat concave, margins acute, thin; flanks sloping obliquely, purple to black; ventral face medianly keeled. Scales in 2 ventral rows, obliquely triangular, deep purple to lightly pigmented, body ± 675 µm long, at margins few small papillae, base crescentic, 825-925 µm wide, narrowed above, not constricted where joined to 1 or 2(3) lanceolate appendages, equally long or not, length 675-925 µm, tapering above to single apical cell, basally ± 375 µm wide, up to 20 smaller oil cells scattered throughout scale. mostly hyaline, walls thin, slightly thickened at corners, 5- or 6-sided, 30.0-45.0 x 17.5-20.0 µm; air pores slightly raised, simple, ± 10.0 x 7.5 µm, surrounded by innermost ring of small, collapsed cells, and then by 2 concentric rings of 5-7 larger cells in each. Assimilation tissue 200-250 µm thick, air chambers small, empty, in 2 or 3 storeys, bounding walls chlorophyllose; storage tissue confined to keel, cell walls porate, thickened, often with striate network of bands; oil cells scattered throughout tissues. Autoicous or monoicous. Androecia in sessile cushions on ventrolateral innovations or at base of main branches, antheridia immersed, opening above into raised, purple papillae. Gynoecial receptacles proximal to apical notch of main branch, single, occasionally paired at apices of 2 furcate branches, almost sessile when young, at maturity raised on stalk; carpocephalum ± 3 mm across, µmbonate, air pores compound, slightly raised, sometimes quite conspicuous, (1-)3-5(-6) capsules borne below. Stalk arising ± 1 mm proximal to branch apex in notch, foot slightly wider than at midlength, width ± 575 µm, with single rhizoid furrow, length variable, 2.5-18.0 mm, white or reddish purple, at summit (and along length) numerous pale, occasionally purple paleae, some very long, up to 8400 µm, others 1250-2750 µm, base ± 100 µm or 4 cells wide, tapering to single apical cell. Involucre membranous, partly covering capsule. Pseudoperianths descending obliquely downward, extending ± 1100 µm beyond involucre and divided into 15 segments, tapering toward connate tips. Sporophyte with globose capsule, ± 600 µm diam. Spores (102-)125-140 µm diam., triangular-globular, yellow; wing undulate, 20 µm wide, margin crenulate; distal face convex, centrally with (4-)6-9 complete alveoli, ± 32.5 µm wide, outer alveoli incomplete, ridges up to 12.5 µm high, seldom extending across wing, smaller, subsidiary alveoli, 2.5-5.0 µm wide (and occasionally even further divided up), generally covering floor of larger alveoli and extending over crests of main ridges; proximal face with prominent triradiate mark, its arms 15 µm high and continuous from pole across wing to margin, each of 3 facets with complete or mostly incomplete alveoli, main ridges sometimes extending across wing, small subsidiary alveoli covering floor and ridges of main alveoli, as well as arms of triradiate mark. Elaters ± 145 µm long, 12.5 µm wide in centre, slightly tapering to ends, bispiral, yellow.

  • Provided by: [B].e-Flora of South Africa
    • Source: [
    • 2
    • ]. 

    Habitat

    Dense mats on clayey soil or on weathered, soil-covered rocks at seepages or riverbanks, between rock crevices and under ledges.

  • Provided by: [B].e-Flora of South Africa
    • Source: [
    • 2
    • ]. 

    Distribution

    Northern, Western and Eastern Cape.

  • Provided by: [B].e-Flora of South Africa
    • Source: [
    • 2
    • ]. 

      Bibliography

    • 1 Hepat. S. Africa
    • 2 Perold, SM. 1999. Hepatophyta. Fl. S. Africa (1,1): 1 - 252.

     Information From

    Aytoniaceae
    World Flora Online Data. 2017.
    • A CC0 1.0 Universal (CC0 1.0).
    e-Flora of South Africa
    e-Flora of South Africa. v1.21. 2018. South African National Biodiversity Institute. http://ipt.sanbi.org.za/iptsanbi/resource?r=flora_descriptions&v=1.21
    • B All Rights Reserved
    World Flora Online consortium
    http://www.worldfloraonline.org/organisation/WFO
    World Flora Online Data. 2018.
    • C CC0 1.0 Universal (CC0 1.0).