Four Fungi on the Endemic Species of Rubus in New Zealand.

By B. Jean Murray, B.Sc., Assistant Mycological, Cawthron Institute, Nelson.

intermixed with and difficult to distinguish from the hyphae of the mycelium, straight to much contorted or knotted, occasionally slightly branched, hyaline or very rarely faintly fuliginous, 25–100 mmm. long or exceptionally up to 1.5 times the width of the perithecium (usually equal to one half to the whole diameter of perithecium), 3–5 mmm. thick. (Figs. 2 & 3).

There are 4–17 asci in each perithecium; paraphyses are absent; asci 8-spored, saccate to ovate-oblong, often irregular in shape, 58–82 mmm. long by 28–36 mmm. wide, with a short broad stalk 8–13 × 5–6.6 mmm.; wall of ascus 1.7 mmm. wide. (Fig. 4.)

The ascospores are continuous, hyaline, almost spherical to broadly elliptical, 13–21.5 × 10–12.4 mmm., with granular contents. (Fig. 5.)

The conidia are continuous, hyaline, rounded, or oblong-elliptical to oblong-cylindrical with bluntly rounded ends, ranging from 28–40 mmm. long by 13–18 mmm. wide. (Fig. 6.)

Habitat,—On living leaves and twigs of Rubus australis Forst. West Coast Road, Nelson, 15/4/25., K. M. Curtis (Myc. Herb. No. 354).

Five species of Erysiphe are recorded for New Zealand, but in the major features of number, shape and size of asci and ascospores the fungus on Rubus agrees only with E. carpophila Syd. (Sydow, 1924, p. 294) on Weinmannia sylvicola Sol.

In the latter fungus, however, the perithecia are somewhat larger and their appendages longer. Moreover, in the single set of material from which the description of E. carpophila was drawn up, it occurred on the capsules only, the leaves being uninfected. But in view both of the agreement of the fungi in their more important characteristics and also of the wide range of hosts upon which the common species of Erysiphe are found, it seems advisable at present, considering our ignorance of the distribution of Erysiphe on native plants, to record the form on Rubus as a form of E. carpophila rather than to assign it immediately to a new species. The new form is therefore designated E. carpophila Syd. var. rubicola.

Phyllosticta variabilis Peck.

This fungus was found causing leaf-spots on Rubus cissoides A. Cunn. and Rubus australis Forst. growing along the banks of a creek in Mr. Whitwell's bush, Wakapuaka. It was also found on twigs of R. cissoides infected with Pestalozzia antennaeformis. The following is a description of the fungus and its appearance on the host:—

There may be one to three large spots upon each leaflet with occasionally in addition several much smaller spots; the spots may be either terminal forming light brown dead areas at the tip, sometimes extending to 3 cm. from the apex, marginal when they are roughly semicircular and up to 1 cm. in diameter, or internal and circular up to 0.5 cm. in diameter. The infected spot starts in all cases as a small purplish or dark red area which, as it extends and ages becomes zoned, showing a central white or greyish white portion surrounded in turn by a light brown zone (which, if large, may show secondary zoning), a chocolate-brown or blackish zone, and, finally,

The form of Phyllosticta variabilis Peck (1884, p. 138) occurring on the local species of Rubus agrees in all major features with that originally described, which was found on Rubacer odoratus (L.) Rydb. (Rubus odoratus, L.) but exhibits slight variations, such as the smaller number and somewhat larger average size of the pycnidia and their occurrence at times on the lower surface of the leaf. These variations, however, are not greater than might be expected to be shown by cultures of any organism on different hosts. The possibility of the present species being either P. Ruborum Sacc. or P. Dearnessii Sacc. also occurring on Rubus sp., is excluded by the small size of the spores in the two last-named fungi.

Pestalozzia antennaeformis n. sp.

The minute acervuli of this fungus were found uniformly and densely distributed over large cankered areas on living stems of an isolated bush of Rubus cissoides A. Cunn. growing in the Botanic Reserve, Nelson, and later on a bush of the same species at Wakapuaka. The cankers stretch from a few inches to several feet along, and wholly or partially surround the stem. The bark is not ruptured except where the acervuli break through the surface, the canker merely appearing as a light brown dead area slightly sunken below and in marked contrast with the green uninfected regions. (Figs. 18, 19.) A search was made for the same fungus on the leaves and, although none was found on the living leaves, dead leaves on the Nelson bush showed on microscopical examination the presence of a species of Pestalozzia identical in character with that on the twigs. Finally the same fungus was discovered on living leaves, but of a different species of Rubus (R. australis) at Wakapuaka. In the latter case a few acervuli occurred on dead spots on the living leaves in conjunction with other fungi; it has not so far been seen on the stems of this species.

The acervuli are numerous, gregarious, scattered over large light brown areas on the living stems, minute, circular, flat then erumpent, 132–165 mmm. in diameter. (Fig. 9.)

The spores are fusoid, straight or curved, 5-celled, constricted at the septa, 21–31.6 × 6.6–9 mmm.; the cells vary in intensity of colour, the three middle ones being olivaceous, darker in the upper two; the basal cell is usually the smallest, light olivaceous to hyaline, with a short pedicel 3–6.6 × 1 mmm. Some young, uncoloured conidia still attached to the acervuli were found with pedicels considerably larger, up to 11.5 × 2.5 mmm., but this was only in very isolated instances. The uppermost cell is smaller than the middle ones, hyaline, conical, bearing a little below the rounded apex and continuous with the cell, usually three, simple, equal, hyaline cilia, the ends of which are most frequently dilated into a small round knob, all reflexed more or less at right angles to the long axis of the spore, 13–50 mmm. long by 1–1.5 wide. Occasionally there may be two or four cilia, and very rarely they may fork. (Fig. 10.)

Habitat,—On living stems and dead leaves of Rubus cissoides A. Cunn., Nelson, 19/7/25 and Wakapuaka, 20/9/25, and on living

leaves R. australis Forst., Wakapuaka, 20/9/25. B. J. Murray (Myc. Herb. Nos. 355a, 355b).

The spores germinate readily in water. The cell above the basal cell or less commonly one of the other cells, swells considerably, appearing lighter in colour than before, and puts forth a germ-tube, or two, which cuts off a wall and rapidly proceeds to form a long, sparsely septate, hyaline hypha, which eventually branches and forms the new mycelium (Fig. 11).

This species of Pestalozzia differs in many respects from the other species recorded on Rubus, most nearly resembling P. longiseta Speg. (Sacc., Syll. Fung., vol. 3, 1884, p. 787) from which it is distinguished by larger spores, shorter pedicels, and the characteristic regularly arranged clubbed cilia which are also, on the whole, comparatively shorter. The present species is therefore considered distinct and is named Pestalozzia antennaeformis n. sp.

Coryneum Ruborum Oud.

This fungus was occasionally found with Pestalozzia antennaeformis on cankers on living stems of Rubus cissoides, and still more rarely on dead spots on living leaves of R. australis.

In view of the fact that the Coryneum found on endemic species of Rubus in N.Z. has a greater range of spore colour and size than is given in the descriptions of C. Ruborum Oud. in Saccardo's Syll. Fung. (vol. 2, 1883, p. 576) and Rabenhorst's Kryptogamen-Flora (vol. 7, 1903, p. 657) a short description of the fungus found locally is given below. However, Zellar (1925, p. 40) describes C. Ruborum as having a range which more nearly approaches that of the N.Z. species which is excluded from C. microstictum B. & Br. by not having honey-coloured spores and from C. foliicolum Fuck., a leaf-dwelling species, by having on the average slightly smaller spores.

The acervuli are scattered, black, circular to elliptical, flat, erumpent, 150–360 × 100–200 mmm. (Fig. 12); the spores are elliptical more obtuse at the apical end, straight or curved, 13–18 × 5–7 mmm., 4-locular, constricted at the septa, yellowish-olivaceous (sometimes with yellow hue predominant, at other times almost fuliginous), basal cell sometimes paler and attentuate, uppermost cell rounded conical; pedicels hyaline, filiform, 15–23 × 1.2–15 mmm. (Fig. 13a.)

Habitat,—On living stems of Rubus cissoides A. Cunn., Nelson, 2/11/25, and living leaves of R. australis Forst., Wakapuaka, 21/9/25, B. J. Murray. (Myc. Herb. Nos. 357a, 357b.)

Spores of this fungus germinate readily in water. Prior to germination the cells swell considerably, becoming almost spherical and much lighter in colour; at this stage the spores may be as much as 25 mmm. long by 13 mmm. wide. Any one or more of the cells may put forth a short germ-tube, which rapidly grows to form a hyaline hypha occasionally septate and about 3–5 mmm. wide, which soon branches to form the new mycelium, (Fig. 13b).