Lejeunea apiculata Sande Lac., Ned. Kruidk.

Renner, M. A., de, Lange P. J. & Glenny, D. S., 2021, A synopsis of Aotearoa / New Zealand Lejeunea (Lejeuneaceae: Jungermanniopsida) and new species in the Lejeunea epiphylla Colenso complex, Arctoa 30 (2), pp. 187-212 : 198

2. Lejeunea apiculata Sande Lac., Ned. Kruidk.

Arch. 3: 421. 1854 [1855].

Original material: none cited, but published in a treatment of new species from Java collected (‘detexit’) by Dr. F. Jughuhn.

Type: Java ( L) non vidimus .

= Lejeunea hawaikiana M.A.M.Renner & de Lange , New Zealand J. Bot. 49: 431. 2011 nom. nov. pro Stenolejeunea acuminata R.M.Schust. , Journal of the Hattori Botanical Laboratory 89: 156 (2000) non Lejeunea acuminata (Lehm. & Lindenb.) Lehm. & Lindenb. , Synopsis Hepaticarum 3: 354 (1845) syn. nov.

Type: New Zealand, North Island, Northland, Radar Bush , R. M. Schuster 95-503 (holotype: F ex herb. R. M. Schuster) .

Schuster (2000) described Stenolejeunea acuminata as distinct from S. apiculata (Sande Lac.) R.M.Schust. due to it’s autoicy, short sterile subfloral innovations, dentate repand female bracts, and asperulate cuticle. Schuster’s (2000) concept of L. apiculata was based entirely on the treatment of Eifrig (1936), and it is significant that neither Eifrig nor Schuster examined the type (s) of L. apiculata ( Schuster 2000 p.159) . Schuster claimed that L. apiculata is dioicous based on his interpretation of Eifrig’s (1936) illustration, which showed a plant with serial gynoecia production and no androecia. However, one of the two New Zealand specimens that Schuster himself attributed to his autoicous Stenolejeunea acuminata similarly bore gynoecia and no androecia, though the gynoecia were not produced in series as in Eifrig’s plant ( Schuster, 2000). Schuster’s interpretation that L. apiculata has a smooth cuticle may be explained by this feature simply being overlooked by Eifrig, and the differences in female bract morphology to variation within and among specimens, the subtle expression of this character, and the difficulties in interpreting the relatively shallow, irregular dentition expressed by L. apiculata (see Lee, 2013), and the fact that Eifrig’s (1936) illustrations were relatively coarse.

Although L. apiculata has been reported for Australia, plants from south-eastern Australia agree more with L. hawaikiana in their autoicy, female bract morphology, and asperulate cuticle. Similarly, the account of Malaysian L. apiculata in Lee (2013) is more compatible with L. hawaikiana as we understand that taxon in New Zealand, than it is with L. apiculata sensu Schuster (2000) , given the Malaysian plants are autoicous, have irregularly dentate female bracts and bracteole and an asperulate cuticle (see Fig. 96, 98 and 99 in Lee (2013) contra the description). Our experience of Australian and New Zealand plants is that the distinctions between L. apiculata and L. hawaikiana presented by Schuster (2000) do not hold, and plants of L. apiculata and L. hawaikiana from Australia and New Zealand are compatible on morphological grounds. Further, our experience of Australian L. apiculata as an autoicous plant with asperulate leaf cell surface ornamentation, having irregularly and shallowly dentate female bracts and bracteole is shared more broadly by other observers from across the distribution of L. apiculata (e.g. Zhu & So, 2001; Lee, 2013). On this basis the fundamental distinctions between L. apiculata and L. hawaikiana break down such that L. hawaikiana cannot be maintained as a separate taxon. Therefore we propose formal synonymy here, and accept that the species present in New Zealand is L. apiculata .

Lejeunea apiculata is widely distributed in Asia, Australasia, and the Pacific including the Cook Islands. In New Zealand Lejeunea apiculata occurs in Northland, and on the Kermadec and Chatham Islands, the latter of which represents the global southern limit at nearly 44°S. Lejeunea apiculata is often encountered as a lithophyte within stream beds, though Schuster (2000) characterised it as an epiphyte. Its acuminate leaf lobe apex orientated perpendicular to the shoot axis and the deeply divided underleaves are both distinctive features.