Rytidosperma pulchrum

Rytidosperma pulchrum
Naturally Uncommon
Naturally Uncommon (NZ TCS)
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Embryophytes
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Clade: Commelinids
Order: Poales
Family: Poaceae
Genus: Rytidosperma
Species:
R. pulchrum
Binomial name
Rytidosperma pulchrum
(Zotov) Connor & Edgar

Rytidosperma pulchrum is a species of true grass in the subfamily Danthonioideae.[1][2] It is endemic to New Zealand and was described as Notodanthonia pulchra in 1963 by Russian-New Zealand botanist Victor Zotov.[3]

Distribution

R. pulchrum is endemic to New Zealand. In the North Island it is found on Taranaki Maunga, the mountains of the Central Volcanic Plateau, and the Kaimanawa, Ruahine and Tararua mountain Ranges.[3] In the South Island it is found in two locations in north-west Nelson (Haupiri Bog and Adelaine Tarn, Douglas Range).[4]

The holotype was collected in 1944 by Victor Zotov at Waikamaka River, c. 1000 metres above sea level in the Ruahine Mountains, on a river terrace in light Nothofagus cliffortioides forest.[4]

Description

R. pulchrum forms small, densely tufted tussocks, sometimes rooting. It forms small panicles on 30 cm culms, each with a few spikelets on slender pedicels. The spikelets are 3-(5)-flowered, with awns exserted from glumes. The lemma have three rows of hairs, two on the lemma and one on the callus. The upper and lower rows of lemma hairs are continuous, the upper hairs slightly smaller than lemma lobes, and the lower row overlapping the upper. The central awn is 3-4.5 mm, similar in length to the palea and smaller than the upper lemma hairs. The palea is 3-3.8 mm, and smaller or equal to the upper lemma hairs. The callus has a few marginal hairs overlapping lower lemma hairs.[4]

R. pulchrum is a diploid species with 2n = 24 chromosomes.[5]

Habitat

R. pulchrum is found in boggy places in subalpine and alpine zones.[4][3]

On Ruapehu, near Turoa, R. pulchrum is described as growing in an alpine flush with fern Asplenium richardii and Polystichum cystostegium; the sedges, Carex acicularis, C. berggrenii, C. druceana, C. enysii, C. lachenalii subsp. parkeri, Isolepis caligenis; grasses, Poa lindsayi, and Rytidosperma nudum, and the herbs Cardamine mutabilis, and C. panatohea.[6]

The holotype was described as growing on a river terrace in light Nothofagus cliffortioides forest.[3]

On the desert road, R. pulchrum was described as living in grassy hollows, stream channels and valley-bottom open grassland amongst much denser shrubland and taller grassland.[7]

Threats

R. pulchrum is listed as Naturally Uncommon in the NZTCS. Its qualifiers are range restricted and sparse.[8]

Ecology

The caterpillars of the At Risk moth Orocrambus jansoni are believed to feed on R. pulchrum. Adult female moths were observed crawling out of R. pulchrum plants during surveys.[7][9]

References

  1. ↑ "Flora of New Zealand | Taxon Profile | Rytidosperma pulchrum". www.nzflora.info. Retrieved 2026-06-26.
  2. ↑ Connor, H. E.; Edgar, E. (1979). "Rytidosperma Steudel (Notodanthonia Zotov) in New Zealand". New Zealand Journal of Botany. 17 (3): 311–337. doi:10.1080/0028825X.1979.10426906. ISSN 1175-8643.
  3. 1 2 3 4 Zotov, V. D. (March 1963). "Synopsis of the grass subfamily Arundinoideae in New Zealand". New Zealand Journal of Botany. 1 (1): 78–136. doi:10.1080/0028825X.1963.10429323. ISSN 0028-825X.
  4. 1 2 3 4 "Rytidosperma pulchrum (Zotov) Connor & Edgar - Flora of New Zealand Series". floraseries.landcareresearch.co.nz. Archived from the original on 2026-01-21. Retrieved 2026-06-27.
  5. ↑ Murray, B. G.; De Lange, P. J.; Ferguson, A. R. (2005). "Nuclear DNA Variation, Chromosome Numbers and Polyploidy in the Endemic and Indigenous Grass Flora of New Zealand". Annals of Botany. 96 (7): 1293–1305. ISSN 0305-7364.
  6. ↑ Lange, Peter James; Heenan, Peter (2019-01-27). "A new Cardamine for the Central North Island". Trilepidea. 182. New Zealand Plant Conservation Network: 5–8.
  7. 1 2 Patrick, Brian; Patrick, Hamish (2013-12-01). "Ecological observations of the eastern Volcanic Plateau endemic grassmoth Ororcrambus jansoni". The Wētā. 46: 13–19.
  8. ↑ de Lange, Peter J.; Gosden, Jane; Courtney, Shannel P.; Fergus, Alexander J.; Barkla, John W.; Beadel, Sarah M.; Champion, Paul D.; Hindmarsh-Walls, Rowan; Makan, Troy; Michel, Pascale. "Conservation status of vascular plants in Aotearoa New Zealand, 2023" (PDF).
  9. ↑ "PlantSynz - Invertebrate herbivore biodiversity assessment tool: Database". plant-synz.landcareresearch.co.nz. Retrieved 2026-07-06.