J OURNAL of the A DELAIDE B G OTANIC ARDENS AN OPEN ACCESS JOURNAL FOR AUSTRALIAN SYSTEMATIC BOTANY flora.sa.gov.au/jabg Published by the STATE HERBARIUM OF SOUTH AUSTRALIA on behalf of the BOARD OF THE BOTANIC GARDENS AND STATE HERBARIUM © Board of the Botanic Gardens and State Herbarium, Adelaide, South Australia © Department of Environment, Water and Natural Resources, Government of South Australia All rights reserved State Herbarium of South Australia PO Box 2732 Kent Town SA 5071 Australia J. Adelaide Bot. Gard. 22 (2008) 1–4 © 2008 Board of the Botanic Gardens & State Herbarium, Government of South Australia © 2008 Department for Environment & Heritage, Government of South Australia A new species of Marsilea (Marsileaceae) from arid Australia D.E. Albrechta & R.J. Chinnockb a Northern Territory Herbarium, Department of Natural Resources, Environment and the Arts, P.O. Box 1120, Alice Springs, Northern Territory 0871 E-mail: [email protected] b State Herbarium of South Australia, Plant Biodiversity Centre, P.O. Box 2732, Kent Town, South Australia 5071 E-mail: [email protected] Abstract Marsilea cryptocarpa Albr. & Chinnock is a new fern from three widely disjunct populations growing in cracking clay depressions in arid central Australia. Superficially it is similar to M. drummondii A.Braun and is probably mistaken for vegetative plants of this species. Marsilea cryptocarpa is readily distinguished from M. drummondii by the dense cluster of very small short-stalked sporocarps that are completely enveloped in cottony hairs. Its conservation status is considered ‘data deficient’. Introduction densely cottony hairy with hairs 1.5–7 mm long, those towards base of stipe longest, sometimes glabrescent. A localised population of a distinctive new species of Leaflets obdeltoid, pulvinate, 8–35 mm long, 8–35 mm Marsilea L. was discovered in July 2000 approximately wide, flanks straight, outer margins rounded, crenate, 300 km north of Alice Springs. This remained the sometimes deeply so, initially villose on under surface only known location until 2007, when two additional with mostly ascending hairs c. 0.8–1.5 mm long forming specimens, from the Lake Eyre region and Simpson a thick indumentum, sparsely to moderately densely Desert, were located in the collections held at the State hairy on the upper surface with hairs appressed to Herbarium of South Australia (AD) and Alice Springs ascending, c. 0.5–1 mm long, later leaflets glabrous on Herbarium (NT), respectively. This new species was both surfaces or hairy in patches on under surface, green included in a recent treatment of ferns of the Northern finally turning orange-brown from the margin inward; Territory (Short et al. 2003) under the name Marsilea venation obscure except in older dried leaves, veins (Neutral Junction entity). The opportunity is taken close, anastomosing. Sporocarps closely packed together here to formally describe the species to facilitate its and enveloped by dense cottony hairs to such an extent recognition and conservation. that individual sporocarps are difficult to discern, 6–12 Taxonomy in a row on one side of the stipe base; stalks yellowish- brown, simple or sometimes two arising from the same Marsilea cryptocarpa Albr. & Chinnock, sp. nov. point and appearing branched, 1–2 (–3) mm long, fine Ab omnibus aliis speciebus Australianis sporocarpis and c. 0.2 mm wide at midpoint, broader towards base, minimis in fasciculis densis quoque 6–12 sporocarpio hairy to almost glabrous, shorter than or rarely equal occultibus in pilis longis ad basim stipitis, conceptaculi to the conceptacle, rather fragile and readily breaking; dente superno vix evoluto vel absenti et inferno conceptacle subrectangular to obtusely triangular in plerumque absenti differt. lateral view, oblong-narrow elliptic in dorsiventral Typus: WNW of Claypan Bore, Neutral Junction cross-section, dorsally slightly convex to almost flat, Station, N.T., 20 Oct. 2006, D.E.Albrecht 12094 & P.K.Latz; holo: DNA A112376; iso: NT, AD, BRI. ventrally curved, 2–3 mm long, 2–3 mm wide, densely Marsilea (Neutral Junction entity): Short et al., Beagle 19: and persistently cottony hairy with hairs 3–6 mm long; 29 (2003). lateral ribs obscure or faint beneath hairs, minute pits Marsilea sp. Neutral Junction (D.E.Albrecht 9192): Albrecht on surface apparently absent; raphe distinct, attached et al., Vasc. Pl. Checkl. S. Bioreg. Northern Terr. (ed. 2): along c. three-quarters the length of the conceptacle 34 (2007). base; inferior (lower) tooth absent or rarely represented Perennial fern with ventrally attached filiform snow by a slight protuberance; superior (upper) tooth absent white (aging fawn or yellowish) hairs over most parts, or obscure and represented by a yellowish-orange hairs slightly dilated towards attachment. Rhizome protuberance where the basal and dorsal sides of the long-creeping, branched, rooting at the nodes, initially conceptacle meet. Megasporangia 2–5 per sporocarp, densely hairy becoming sparsely hairy or glabrous later; oval, c. 1-1.2 x 0.6-0.9 mm, white, apical cap brown; hairs 3–7 mm long. Fronds usually clustered. Stipe embedded in mucilage containing numerous small stout, to c. 20 cm long, 0.8–1.3 mm diameter, initially microsporangia. Fig. 1–4. 1 D.E. Albrecht & R.J. Chinnock J. Adelaide Bot. Gard. 22 (2008) Fig. 1. Marsilea cryptocarpa. a plant habit; b arrangement of frond leaflets with enlargement (above) showing anastomosing veins; c–d upper and lower surfaces of leaflets showing variations in hair density; e–f front and side view of stipe base showing developing sporocarps (hairs removed); g lateral view of sporocarp with hair partially removed to show poorly developed tooth and enlargement of hair; h dorsal view of sporocarp (hairs removed); i longitudinal section through sporocarp showing two megasporangia embedded in mucilage with numerous microsporangia (small circles); j top and side view of megasporangium. Scale bars: a–b 10 mm; c–d 5 mm; e–f 5 mm; g–j 0.5 mm. a–c, e–j Albrecht & Latz 12094; d Weber 5837. 2 J. Adelaide Bot. Gard. 22 (2008) New species of Marsilea (Marsileaceae) Fig. 2. Marsilea cryptocarpa population at Neutral Junction Station. Fig. 3. Branch of Marsilea cryptocarpa showing the crowded stipe D.E.Albrecht 12094 & P.K.Latz. bases and the dense matted hair enveloping the rhizome and sporocarps. A small portion of hair has been removed to show the hidden sporocarps. Distribution and habitat. Marsilea cryptocarpa is currently known from only three widely separated sites (see Fig. 5). Two occur in the Northern Territory: one approximately 300 km north of Alice Springs and the other approximately 280 km ESE of Alice Springs. The only known South Australian population is in the Lake Eyre region some 1000 km to the south-southeast of the northern-most Northern Territory population. Due to its superficial resemblance to some forms of the widely distributed Marsilea drummondi A.Braun, the species may have been overlooked and be more common than might appear, especially if growing sympatrically with other species with obvious sporocarps which would be collected in preference to an apparently ‘vegetative’ plant. At the type locality in the Northern Territory Marsilea cryptocarpa is localised in clay depressions on an open stony plain, where it forms monospecific Fig. 4. Enlargement to show three sporocarps of Marsilea cryptocarpa patches, one of which is approximately 1 km by 200 and orange (when fresh) protuberance. m. The clay depressions are periodically water-filled and have a distinctive smooth cracking chocolate-like known (3K) sensu ROTAP (Briggs & Leigh 1996) is surface texture when dry. The type locality is within the the appropriate conservation code. Based on present Burt Plain bioregion (Albrecht et al., 2007) and habitat knowledge the species is unreserved. of this nature appears to be very rare in that bioregion. The other Northern Territory population occurs in the Etymology. The specific epithet is derived from the Simpson-Strzelecki Dunefield bioregion (Albrecht et Greek crypto-, covered, hidden, concealed and -carpos, al., 2007), which would appear to have more areas of fruit; referring to the hidden sporocarps characteristic of suitable habitat. The South Australian population appears this species. to occur in a similar habitat to the Northern Territory Notes. Marsilea cryptocarpa is distinguished from other populations, being described as a muddy pool on a Australian species of Marsilea by the dense clusters gibber plain (plain mantled by loose rock fragments). of small (to 3 mm long) short-stalked conceptacles Conservation status. Although the species could be that have at most one poorly developed basal tooth regarded as threatened on the basis of the limited and are covered in dense long cottony hairs. The hairs population numbers, the lack of focused field survey on adjacent sporocarps become entanged to such an in areas of potentially suitable habitat and its close extent that individual sporocarps in a cluster are not superficial resemblance to infertile specimens of distinguishable without microscopic examination. It Marsilea drummondii would suggest that ‘DD’ (data is for this reason that fertile specimens are frequently deficient) sensu IUCN (2001) or nationally poorly passed over as being sterile. 3 D.E. Albrecht & R.J. Chinnock J. Adelaide Bot. Gard. 22 (2008) Identification key The key to Marsilea in Flora of Australia (Jones 1998, p. 167) should be modified as follows: 1: Stalks of sporocarp c. as long as conceptacles 4. Conceptacles to 3 mm long 5. Sporocarps 6–12 in a dense row at very base of stipe; conceptacles completely hidden in long cottony hairs 3–6 mm long, upper tooth poorly developed, lower tooth usually absent ............ M. cryptocarpa 5: Sporocarps solitary on in small groups of < 6 at stipe bases; conceptacles not hidden by indumentum, hairs < 3 mm long, two well-defined teeth present 5A. Conceptacles ribbed; upper surface concave ..... ............................ M. costulifera 5A: Conceptacles not ribbed; upper surface convex .. ............................... M. crenata 4: Conceptacles more than 4 mm long Fig. 5. Distribution of Marsilea cryptocarpa. Acknowledgements Using the treatment of Jones (1998), fertile specimens of Marsilea cryptocarpa would key to M. We thank Peter Bostock for his comments on crenata C.Presl or M. costulifera D.L.Jones. However the manuscript and for checking specimens in BRI both of these species are less robust with finer stipes and herbarium; directors and curators of MEL and CANB smaller leaflets, the sporocarps are readily detected, and for allowing access to specimens; Hellmut Toelken for the conceptacles have shorter hairs (<3 mm long) and at checking the Latin diagnosis; Tim Collins for cultivating least one prominent basal tooth. Marsilea cryptocarpa specimens at the Alice Springs Desert Park; Angus is probably more likely to be confused with Marsilea Duguid for preparing the distribution map; and Gilbert drummondii as the latter can have a similar disposition Dashorst for preparing the illustration. and similar sized fronds, crenate leaflets and dense References masses of cottony hairs on the rhizome, stipe bases and Albrecht, D.E., Duguid, A.W., Coulson, H., Harris, M.G. & primordial fronds. However, Marsilea drummondii is Latz, P.K. (2007). Vascular Plant Checklist for the Southern readily separated from Marsilea cryptocarpa when fertile Bioregions of the Northern Territory: Nomenclature, as its conceptacles are long-stalked and are considerably Distribution and Conservation Status (ed. 2). (Northern larger (4–9 mm long) with prominent teeth. Territory Herbarium: Alice Springs). Briggs, J.D. & Leigh, J.H. (1996). Rare or Threatened Specimens examined Australian Plants (rev. edn). (CSIRO: Collingwood). NortherN t erritory: WNW of Claypan Bore, Neutral IUCN (2001). IUCN Red List Categories and Criteria: Version Junction Station, 25 July 2000, D.E.Albrecht 9192 (NT A099150); 3.1. (IUCN, Gland, Switzerland). 112 km SSE of Atula Homestead, Simpson Desert, 19 Sep. 2001, Jones, D.E. (1998). Marsilea. In: Orchard, A.E. (ed.), Flora P.K.Latz 18019 (NT A0104483). of Australia 48: 166–172. (ABRS: Canberra; CSIRO: south australia: Lake Eyre: c. 20 km S of Stuart Creek Collingwood). Homestead, 6 Oct.1978, J.Z.Weber 5837 (AD 97842372). Short, P., Dixon, D. & Osterkamp Madsen, M. (2003). A review of the ferns and fern allies of the Northern Territory. The Beagle, Records of the Museums and Art Galleries of the Northern Territory 19: 7–80. 4