Gackstroemia weindorferi (Herzog) Grolle

Engel, John J., 2013, Austral Hepaticae 50. Gackstroemia in New Zealand, together with an interesting new species, Phytotaxa 118 (1), pp. 9-21 : 16-19

Gackstroemia weindorferi (Herzog) Grolle ( Fig. 3 )

Lepidolaena weindorferi Herzog in Verdoorn Ann. Bryol. 6: 103. 1933. Gackstroemia weindorferi (Herzog) Grolle, J. Hattori Bot. Lab. 30: 20. 1967. Type:— AUSTRALIA,. Tasmania, Wilmot, 1927, Weindorfer .

Plants at maturity with principal axis ascending or the entire plant erect, copper-red or pale brown and with stems deep red brown and older sectors of plant warm brown and then, at times, at most tinged with magenta, medium in size, 9–17 mm wide (widest point of opposing primary branch tips). Branching regularly 2(3)- pinnate (3º branches completely lacking in some populations), mostly 2-pinnate, at times 3-pinnate, commonly with some secondary branches bearing 3º branches while others lack them, the primary branches stiffly spreading, always flat and not twisted toward base of main axis; ultimate branches with first branch underleaf bilobed, the lobes typically uniformly galeate, occasionally with upper lobe explanate. Stems rigid, the cortex of main axes in 2–4 layers of strongly thick-walled, bast-fiber like, pigmented cells; medulla of thin-walled, pigmented cells. Rhizoids sparsely and locally developed, in tight fascicles at base of underleaves of main stem. Leaves of main shoot with dorsal lobes imbricate, horizontal or a little elevated above stem, weakly convex and with leaf tips plane or a little decurved, weakly asymmetrically orbicular-ovate to ovatedeltoid to (with an increase in dilation of dorsal margin), strongly asymmetrically broadly ovate, the apex typically abruptly short to more prominently apiculate and terminating in a single cell or a hyaline uniseriate row of 2–3 cells, the tip cell moderately to distinctly elongate and tapering to a sharp summit, the lobe apex at times narrowly acute; dorsal margin (= margin nearest stem) plane and not reflexed, with to 5 small teeth or short cilia or entire, the teeth comprised of a single cell or a uniseriate row of 2–3(4) cells, the cells of cilia (esp. the terminal cell) distinctly thick walled, the margin narrowed to the base grading to weakly to moderately cordate to at most moderately auriculate; ventral margin with armature similar but the cilia often more numerous and longer (with a uniseriate row of to 6 cells). Ventral lobe deeply and asymmetrically divided into a nearly always explanate lobule and a much larger (esp. wider) stylus. Lobule (on leaves of main shoot) narrowly elongate, nearly always explanate and with margins variably reflexed and delimiting a rather broad groove, the lobule thus variously sulcate, only exceptionally and locally transformed into a welldeveloped water sac, the lobule margins otherwise entire or at times with a cilia at the summit and a few cilia on the margins. Stylus cucullate, the margins distinctly reflexed, the stylus shape variable: elliptic to ovate to suborbicular to suboblate, entire or with a few cilia, the free margin often distinctly decurrent. Leaves of 2º branches smaller, simpler, lacking a third lobe (stylus), with dorsal lobe margins dentate-short ciliate or long ciliate, the armature ± regularly spaced, hyaline. Leaves of ultimate branches with dorsal lobe margins long ciliate, the armature ± regularly spaced, hyaline, composed of 2–4 elongate, capillary cells, the longer ones subequal to width of dorsal lobe, the lobules saccate, narrowly elongate-clavate, with a lateral slit, the lobule summit with a long awn composed of 4 elongated cells. Cells with trigones bulging and knotlike, not confluent, the intervening walls between trigones thin, the lumina boundary irregularly sinuate (the uneven line defined by the alternation of bulging trigones and intervening thin walled areas), the median cells 24–34 µm wide × 28–36 µm long; surface smooth. Underleaves of stems and primary branches large, imbricate, ovate-oblate to subreniform, bilobed to ca. 0.2–0.4, the lobes never transformed into water sacs, typically reflexed and canaliculate-cucullate, terminating in a uniseriate row of (2)3–5 (up to 8 in some Tasmanian populations) elongated, often capillare, cells with swollen septa; lamina with margins narrowly and sharply reflexed to revolute and with the reflexed portion confluent with the recurvature of the lobes, the lamina margins entire or with numerous spinose teeth grading to rather long cilia, becoming narrowed and angled to base (ca. 45º to at most 90º), not cordate or auriculate, with tissue adjacent to apex and base of U-shaped insertion line forming an inverted triangle. Underleaves of ultimate branches nearly uniformly saccate, rarely and sporadically with one of lobes explanate, the water sacs with long awns composed of 4–5 elongated cells.

Plants dioecious. Androecia numerous, confined to apices of secondary and tertiary (ultimate) branchlets, rather short and compactly spicate, straight and not decurved; bracts in 3–4(5) pairs, imbricate, bilobed to less than 0.35, the dorsal lobe much larger, broadly acute, the apex with an awn, the dorsal margin of the dorsal lobe and lamina with several inconspicuous, unicellular, sharp teeth, the lamina margin sharply reflexed toward the base, the ventral lobe with reflexed margins, tapering to a canaliculate-cucullate apex, the summit with a short to long awn, the lobe margins entire, the entire base strongly ventricose; antheridia 1 per bract, the subspherical body occupying a rather small portion of the ventricose bract base, the stalk uniseriate, ca. 15 cells; bracteoles present throughout, shallowly bilobed, strongly spreading to squarrose, the lobes margins strongly reflexed and lobe apex canaliculate-cucullate, the apex with a short awn. Gynoecia with the coelocaule erect, fleshy, narrowly cylindrical-clavate, with sterile archegonia inserted on the caplike, membraneous shoot-calyptra, the coelocaule devoid of paraphyses or paraphyllia, hidden even at maturity by the 4-5 series (gyres) of sheathing, mutually closely shingled bracts and bracteoles, forming a compact, budlike structure; bracts membraneous, narrowly ovate, bifid to ca. 0.2 or less, by the narrowly acute lobes, the lobes and distal sector of lamina densely and copiously armed with long, tortuous cilia, the basal sector of lamina distantly and sparsely armed to subentire; bracts of innermost series inserted near perianth base and closely entheathing it, a little larger than the gyre immediately below, with 2 of the bracts distinctly connate, the third free; perianth present, not or slightly exserted beyond bracts, ± cylindrical, with complete fusion of components to form a complete ring or true perianth, the ring sometimes interrupted (on ventral side of perianth) by 2 of margins totally free to the base (but with the 2 free margins broadly overlapping), the perianth narrowing toward the ± contracted mouth, with several broad plicae, the mouth and free margins densely fringed with markedly tortuous cilia like those of bracts below, the cilia mostly uniseriate to base, with to 13 cells in the uniseriate row, the cells toward base of cilia thick walled, becoming weakly thick walled distally.

Capsule short cylindrical to slenderly long cylindrical, the wall 74–100 µm thick, of 3(4) or 3–4(locally 5) layers, the outer layer of cells very high, 1.7–2.8X higher than wide, the cells within with thin and delicate walls, the cells collapsing with age, the inner face of the valve with local patches of cells that are often sloughed off; outer layer of cells quadrate to rectangular, with all longitudinal walls with thick, even, often ± lens-like, orange-brown sheets of wall material, without nodular thickenings, the transverse walls thin or with moderate even thickenings; innermost layer of cells irregularly rectangular, with weak, often ill-defined, weakly pigmented semiannular bands, the bands often incomplete.

Spores 47–58 µm, the wall distally irregularly reticulate, with irregular, low, fine ridge-like vermiculae that frequently and irregularly anastomose to form a loose and variable network of areolae; proximal field 30- 37 µm wide, distantly and irregularly finely papillose-vermiculate. Elaters tortuous, 6.5–12.5 µm wide, 1- or 2-spiral throughout, or 2-spiral but with the tips 1-spiral, or 2-spiral but locally 3-spiral in median sector, the spirals broad, 2.9–4.3 µm wide, closely wound.

Distribution:— New Zealand: Stewart Is. (5-500 m), South Island (525-920 m), North Island (1200-1280 m); Australia: Tasmania, Victoria, New South Wales.

Comments:—Among the New Zealand species of Gackstroemia , G. weindorferi is median in the size range between the vigorous G. novae-zelandiae and the small G. alpina . At first glance plants of G. weindorferi appear to be most closely related to G. novae-zelandiae , primarily due to the larger plant stature and general similarity in aspect. However, a number of differences will separate the species; these are discussed under that G. novae-zelandiae . On closer examination, G. weindorferi has a much greater similarity to G. alpina than to G. novae-zelandiae . Gackstroemia weindorferi and G. alpina may be distinguished as follows. Plants of G. weindorferi are 9–17 mm wide (at the widest point between opposing primary branch tips) vs. 6–11 mm wide in G. alpina . In G. weindorferi the curvature of the dorsal lobe apex of main shoot leaves is interrupted by a narrowly acute to abruptly and prominently apiculate process, and the tip cell of the process is always well defined and moderately to distinctly elongate ( Fig. 3 : 1-3). In G. alpina the dorsal lobe apex of main shoot leaves is narrowly to broadly rounded with a curvature that is smoothly continuous and not interrupted by an angulation at the summit. At times an apiculus is differentiated in G. alpina , but the curvature of the apex nevertheless forms a smooth continuum. And, in G. alpina , the tip cell of the process is ill-defined and commonly only weakly elongate (only exceptionally moderately elongated). Moreover, the tooth at the lobe apex at times is reduced to an inconspicuous angular creniform projection. In G. weindorferi the underleaf lobes of primary branches are either explanate throughout or (at times) saccate in the distal half or less of the branch vs. primary branch underleaf lobes frequently all or mostly saccate in G. alpina . Plants of G. weindorferi are rust-colored to copper-red, and only sporadically weakly tinged with magenta and then inconsistently so. Plants of G. alpina , on the other hand, have deep red to magenta or piceous pigmentation.

Phases of G. weindorferi that are smaller and have lobules of main shoot leaves sporadically saccate should be handled with care to distinguish them from G. alpina .

Notes:—The lobule of main shoot leaves is narrowly elongate, typically explanate, and variously sulcate due to margins variably reflexed to delimit a rather broad slit-like incision. The lobule on main shoot leaves is only exceptionally and locally transformed into a well-developed water sac.

Figures

FIGURE 3. Gackstroemia weindorferi (Herzog) Grolle. 1. Two leaf pairs of main shoot, dorsal view; note dorsally interlocking insertion lines and plane and not reflexed dorsal margin of dorsal lobes. 2. Two leaf pairs of main shoot, ventral view (underleaves removed for clarity, only the scars indicated); note first branch underleaf (= fbu); (drawn to same scale as fig. 1). 3. Leaf from main shoot. 4. Median cells of dorsal lobe. 5. Underleaf, in situ, of main shoot, ventral view. 6. Underleaf. 7. Distal sector of underleaf lobe. 8. Tertiary branch showing saccate lobes of both first branch underleaf and underleaves of branch (ventral view). Note the bilobed first branch underleaf (= fbu) of the secondary branch (= 2º br), and the next two underleaves of the branch, the first bilobed similar to the first branch underleaf, the second with both lobes saccate. Underleaf scars are shown on short sector of primary branch (= 1º br). 9. Innermost bracts. 10. Perianth (flattened). 11. Spore and elater drawn to same scale; note proximal face. 12. Elater. (Figs. 1, 2, 5, 8, from Engel 19039A, New Zealand, South Is., Westland Prov., Paparoa Range, ridge immediately N of Sewell Peak; 3, 6, 7, from Engel 13154, Tasmania, E side of Tasman Peninsula, W facing, upper slope of Tatnells Hill; 4, 9-12, from Engel 12912, Tasmania, Mt. Field National Park, off Lake Dobson Road.)