on Carex chathamica Petrie
Specimens examined: Rekohu, Mahahatau Creek, J. F. Findlay, Jan 1955 (PDD 42220 - CHR 97202); east of Te Whanga Lagoon, J. F. Findlay, Jan 1955 (PDD 42221 - CHR 97201); Owenga, 11.111.1983, E. H. C. McKenzie (PDD 44228 - holotype). Rangiauria, B. G. Hamlin, 1 Dec 1957 (PDD 41170 - WELT 3325).
on Carex trifida Cav.
Specimen examined: Rangatira (South East Island), B. Bell, Dec 1961 (PDD 42218 - CHR 158261, PDD 42219 - CHR 158260).

Uredinia amphigenous, mainly on lower (abaxial) surface, cinnamon-brown, pulverulent, up to 1 mm long or confluent and linear, surrounded by the ruptured epidermis. Urediniospores (28-) 33-39 (-46) x (24-) 26-31 (-35) µm, globose or broadly ellipsoidal, wall (1.5-) 2-3.5 (-4) µm thick, golden-brown, echinulate, germ pores 3-4, equatorial.

Urediniis plerumque hypophyllis (abaxialibus), cinnamomeo-brunneis, pulverulentibus, usque ad 1 mm longis. Urediniosporae (28-) 33-39 (-46) x (24-) 26-31 (-35) µm, globosae vel late ellipsoideae, membrana (1.5-) 2-3.5 (-4) µm crassa, aureo-brunnea, echinulata, poris germinationis 3-4, aequatorialibus. In foliis cyperaceae speciei Carex chathamica Petrie et C. trifida Cav.

There are four species of rust fungi recorded on Carex in New Zealand. Urediniospores of Uredo chathamica differ from those of the four Puccinia spp. in size and number of germ pores. Carex chathamica is endemic to the Chatham Islands, while C. trifida, which is indigenous to the South Island and the subantarctic islands of New Zealand, also occurs in Chile and the Falkland Islands.

Holotypus PDD 44228.

Other specimens examined: Auckland Islands, Enderby Island,Sandy Bay, on Carex trifida Cav. [Cyperaceae], March 21,2000, E.H.C. McKenzie (PDD 83426 – II). Chatham Islands, Rekohu, Owenga, March 11, 1983, E.H.C. McKenzie(PDD 44228 – II – holotype of Uredo chathamica).

Uredinia amphigenous, mainly on lower (abaxial) surface, cinnamon-brown, pulverulent, linear, up to 2 mm long or longer when confluent, surrounded by the ruptured epidermis. Urediniospores 33–49 x 27–33 µm (av. of 39 spores, 41.4 x 30.0 µm), subglobose, ellipsoidal or obovoid, wall 2–3.5 µm thick, light brown, echinulate, germ pores 3, equatorial. Telia on lower (abaxial) surface, dark brown toblack, compact, up to 1 mm long, surrounded by the ruptured epidermis. Teliospores 43–56 x 18.5–21 µm, ellipsoid or subclavate, apex rounded, constricted at septum, wall 1–2.5 µm thick at sides, 9–10.5 µm at apex, smooth, light brown; pedicels up to 30 x 4–5 µm, but usually broken shorter, paleluteus.

Uredinia plerumque hypophylla (abaxialia), cinnamomeo-brunnea, pulverulentia, usque ad 2 mm longa. Urediniosporae 33–49 x 27–33 µm, subglobosae, ellipsoideae vel obovoideae, membrana 2–3.5 µm crassa pallide brunnea echinulata, poris germinationis 3 aequatorialibus. Telia hypophylla (abaxialia), atro-brunnea vel nigra, compacta, usque ad 1 mm longa. Teliosporae 43–56 x 18.5–21 µm, ellipsoidae vel subclavatae, ad septum constrictae, membrana ad latera 1–2.5 µm ad apicem 9–10.5 µm crassa levi pallidebrunnea, pedicello usque ad 30 x 4–5 µm pallide luteo.

Notes: The description of the urediniospores matches that given by McKenzie (1991) for Uredo chathamica [(28–)33–39(–46) x (24–)26–31(–35) µm], and a comparison of specimens also indicates that they are conspecific. McKenzie (1991) described U. chathamica based on four collections of a rust fungus on Carex chathamica Petrie and two on C. trifida from the Chatham Islands, New Zealand. None of the six specimens had teliospores. The collection of rust on C.trifida from Campbell Island is the only one to have both urediniospores and teliospores. Unusually, it is the urediniospores of P. chathamica that are quite distinctive from those of four other species of Puccinia known on Carex spp. in New Zealand. The urediniospores are larger than those of the other four species (P. caricina, P. mania G. Cunn., P. maurea G. Cunn., P.rautahi G. Cunn.) and they generally have three equatorial germ pores. The teliospores are less distinctive. In size they are most similar to those of P. maurea and P. rautahi, but are slightly larger. The teliospores of P. rautahi have an acuminate apex whereas those of P. chathamica and P. maurea are mainly rounded.

Campbell Island, Beeman wharf, on C. trifida, March 8, 2000, E.H.C.McKenzie (PDD 83420 – II, III – HOLOTYPE)