Rust Fungi on New Zealand Clematis. By G. T. S. Baylis, Botany Department, University of Otago. [Read by title and abstract before the Otago Branch, April 13, 1954; received by the Editor, April 26, 1954.] Abstract Puccinia, alboclava, n.sp. is microcyclic and known only from seedlings of Clematis indivisa. It differs from P. clavata Syd. in having smaller, thinner-walled, unpigmented teleutospores and in forming lesions that are pale in colour. P. clavata is also microcyclic, and differentiated into physiologic races, a form from C. hexasepala being able to cross to C. indivisa while one on C. foetida could not. The uredospore stage previously attributed to P. clavata is described as Uredo puawhananga n.sp. Pycniospores and aecidiospores of Aecidium otagense Linds. cannot infect Clematis. Species which have been tested unsuccessfully as possible alternate hosts of this fungus are Danthonia cunninghamii, Poa astoni, Uncinia australis, Cross 7 Wheat and I.A.B. *iryecorn. Puccinia alboclava n.sp. Microcyclica et sine spermagoniis. Teleutosori hypophylli, in maculis vix incrassatis usque ad. 1 cm. latis insidentes, nudi, pulvinati, in singulos usque ad. 25 mm. lati sed trans aliquantum maculorum confluentes, isabellini vel mellini. Teleutosporae hyalinae, formibus diversis, 26–54μ longae, 11–18μ latae (medie 41μ × 12μ), episporio levi, plerumque tantum 1μ crasso, interdum apice usque ad 2μ incrassato, pedicello brevi. Habitat. In foliis plantae juvenilis Clematidis indivisae. Holotype. Mt. Maungatua, Otago, New Zealand, 1,300ft., coll. G. T. S. Baylis 9/7/1950, in herbario Plant Diseases Division, Auckland, No. 12685. Paratypes. Mt. Hauhangitahi, Volcanic Plateau, S. D. Baker 1/1954, P.D.D. No. 12894; Steep Hill, Merton, Otago, 800ft., Baylis 11/6/1953, O.U. No. 908; Swampy Spur, Dunedin, 1,500ft., Baylis 6/12/1950, O.U. No. 910; Maungatua, Otago, 1,200–1,500ft., Baylis 31/3/1953, O.U. No. 905. Fig. 1.—Uredospores of Uredo puauhananga (left), teleutospores, epibasidium and germinating basidiospores of Puccinia alboclava (right).

Puccinia alboclava has been found only upon the soft leaves of Clematis indivisa seedlings in the interior of moist montane forests. At present it is known from the vicinity of Dunedin and from the centre of the North Island but it will probably prove to occur in suitable intermediate localities. Species of Puccinia possessing almost colourless teleutospores are rare and this appears to be the first recorded on Clematis. The only other rust producing teleutospores on this host in New Zealand is P. clavata Syd. P. clavata is normally found on mature foliage, its teleutosori are black, and the spores themselves larger (56μ × 19μ), stouter-walled and pigmented. The pale grey to buff colour of P. alboclava lesions readily distinguishes them in the field, and the comparatively delicate spores appear quite colourless when examined microscopically. The microcyclic nature of P. alboclava was confirmed by infecting C. indivisa seedlings with teleutospore inoculum under controlled conditions employing apparatus comparable with that recommended by Arthur (1929, fig. 183). In the first of these experiments few epibasidia were formed by the inoculum and only two lesions developed on plants placed beneath it, but on the second occasion 18 lesions formed. They became recognisable after about a month as pale areas on the lower leaf surface, and a week later had assumed a diameter of about 2.5 mm. with a pale orange centre where the first sori were erupting. Though both experiments were performed in the spring, teleutospores were the first and only spore form produced. The Life Cycle of Puccinia Clavata Syd. The full series of spore forms attributed to P. clavata by Cunningham (1931, p. 147) implies that this species is macrocyclic and autoecious. But Table I shows that the pycnidia and aecidia are unknown apart from the 1928 Weraroa collection, and that the teleutospore and uredospore stages ordinarily occur quite independently. This suggests that P. clavata, which was originally described from teleutospore material alone, is normally microcyclic, a conclusion that has been confirmed by controlled inoculations, details of which are given in Table II. Table II. Controlled Inoculations. A. Employing teleutospores of Puccinia clavata. Date Inoculum on Source Host Tested Result 13/6/51 C. hexasepala Weraroa Sandhills, Wgtn. C. indivisa Many teleutosori 23/8/51) C. foetida Taieri Mouth, Dunedin C. indivisa Nil 14/10/51 6/5/52) 16/11/52 C. foetida Taieri Mouth, Dunedin C. indivisa Nil C. foetida Many teleutosori B. Employing uredospores of Uredo puawhananga. 11/12/53 C. indivisa Swampy Spur, Dunedin C. indivisa Uredosori only (seedlings) C. foetida Nil These experiments also demonstrate the existence of physiologic races of P. clavata. Four attempts to transfer it from C. foetida to C. indivisa failed and this accords with field evidence in that at Dunedin C. indivisa is unattacked by this fungus though it may be plentiful on C. foetida growing in close proximity to it. On the other hand the single attempt to transfer the disease from C. hexasepala to C. indivisa caused heavy infections involving petioles and stems as well as foliage.

It seems inadmissable to retain under P. clavata the widespread uredo-stage found upon Clematis. Primitively P. clavata probably was macrocyclic and the pycnidia, aecidia and uredosori collected at Weraroa in 1928 may all have belonged to a macrocyclic race of the fungus. But these pycnidia and aecidia have not been found since though they have been recently sought in that district. The uredo-stage seems normally to lead a wholly independent existence, so that it does not necessarily agree in pathogenicity with teleutosporic species which occupy the same district. Thus at Dunedin the Uredo is common along with P. alboclava on C. indivisa seedlings and cannot infect C. foetida (Table II B), while P. clavata is abundant on C. foetida and cannot infect C. indivisa. Uredo puawhananga n. sp. Sori hypophylli, aurantini, sed post exsiccationem pallescentes, vel in circibus dispositi vel ubicumque erumpentes, rotundati, epidermide disrupta cingulati, usque ad 1.5 mm. lati, paraphysibus nullis. Uredosporae globosae, ellipticae vel obovatae, 19–29μ longae, 15–24μ latae (medie 23 × 18μ) episporio verrucoso 1–2μ crasso, sine poribus manifestibus. In foliis Clematidis indivisae. Holotype. Swampy Spur, Dunedin, 1,200ft., coll. G. T. S. Baylis 1/3/1954 in herbario Plant Diseases Division, Auckland, No. 12908. The powdery, orange sori about 1 mm. in diameter often disposed in circular groups cannot readily be confused with any other rust on New Zealand Clematis. Coriaceous sun leaves seem to resist attack, but the less heavily cutinized foliage produced in partial shade may yellow and fall as a result of intense general infection. The collections recorded in Table I show that the fungus also occurs on C. hexasepala and the exotic C. vitabla and ranges from the Three Kings Is. to Stewart I. Aecidium otagense Linds. A. otagense infects both C. indivisa and C. foetida in the Dunedin district. Suspensions of aecidiospores have been incubated usually for three days, upon the following species without in any case producing infection: C. indivisa (3), C. foetida (1), Danthonia cunninghamii (3), Uncinia australis (3), Poa astoni (1), Cross 7 Wheat (1), I.A.B. ryecorn (1). The number of separate experiments in which each was involved is given in brackets. C. foetida was the source of inoculum in the attempt to infect this species; in all other cases the inoculum was on C. indivisa. Some spore germination always occurred during the incubation period. On two occasions suspensions of pycniospores washed from several lesions were incubated on C. indivisa without result. Pycniosori of this fungus regularly appear on new infections in the field before the aecidia erupt, and single, isolated lesions commonly fail to develop beyond the pycnidial stage. This, together with the inability of the aecidiospores to infect Clematis supports the expectation that this will prove to be a heterothallic, macrocyclic and heteroecious rust. But it is remarkable for its ability to appear on vines in gardens considerably removed from native vegetation, and repeated searching in areas where it is common has failed to indicate the alternate host involved in completion of its cycle.

Acknowledgments I am indebted to Dr. Basil Howard, Mr. I. D. Parsons and Mr. H. S. Prouse for assistance in collecting and to Dr. G. H. Cunningham and Miss Joan Dingley for the loan of herbarium material. Species names in the genus Clematis are applied as in Cheeseman's (1925) Manual of the N.Z. Flora, and Miss L. B. Moore has kindly confirmed the determination of the host of my Weraroa collection. Allan (1947) has pointed out that C. indivisa should be given Gmelin's name C. paniculata. Some of the travelling expenses incurred during this investigation have been met by a grant from the Research Fund of the University of New Zealand. References Allan, H. H., 1947. Notes on N.Z. Floristic Botany No. 8, Trans. Roy. Soc. N.Z., 76, 594. Arthur, J. C., 1929. The Plant Rusts. Wiley&Sons, Inc., New York. Cunningham, G. H., 1931. The Rust Fungi of New Zealand. John McIndoe, Dunedin.

Table I. Herbarium Material Referred TO Puccinia clavata Sensu Cunningham, 1931. Herb. No. Locality Host Collector and Date Stages O.U. 916 Great I., Three Kings C. indivisa (shade leaves) G. T. S. Baylis, 5/1/53 Uredosori only = Uredo puawhananga n.sp. P.D.D. 12213 Hunua Ra., Ak. ? (juvenile leaves) J. M. Dingley, 1/3/53 " 12909 National Park ? (juvenile leaves) S. D. Baker, 29/1/54 " 1365 Taupo C. hexsepala E. H. Atkinson, 3/1922 " 12105 Taupo C. hexasepala J. M. D., 26/3/53 " 12112 Upper Hutt, Wgtn. C. hexasepala A. J. Healy, 9/3/53 " 12154 Upper Hutt, Wgtn. C. vitalba A. J. Healy, 4/5/53 O.U. 915 Swampy Spur, Dn. C. indivisa (seedlings) G. T. S. B., 6/12/50 O.U. 914, 913 Maungatua, Dn. C. indivisa (seedlings) G. T. S. B, 9/7/50, 31/3/53 P.D.D 12910 Stewart I. C. indivisa (seedlings) J. M. D., 16/2/54 O.U. 909 Totara N., N.Ak. C. foetida G. T. S. B., 28/12/50 Teleutosori only = P. clavata Syd. P.D.D 3070 Weraroa, Wgtn. C. hexasepala G. H. Cunningham, 11/1927 O.U. Weraroa, Wgtn. C, hexasepala G. T. S. B., 2/1952 P D.D 10853 Levin, Wgtn. C. hexasepala I. D. Parsons, 6/1951 " 6128 Whiteman's Va., Wgtn. C. hexasepala A. J. H., 2/1948 " 12051 Featherston, Wgtn. C. hexasepala A. J. H., 17/3/53 " 12102, 12177 Trentham, Wgtn. C. foetida A. J. H., 25/3/53, 19/5/53 O.U. 918 Bot. Gardens, Dn. C. foetida G. T. S. B., 20/10/53 O.U. 912,917 Taieri Mouth, Dn. C. foetida G. T. S. B., 20/8/51, 20/10/53 " 3416 Weraroa, Wgtn. C. hexasepala G. H. C. 10/1928 Pycniosori aecidiosori uredosori