Pleonosporium novae-angliae G.W.Saunders & C.W.Schneider, 2024

Schneider, Craig W. & Saunders, Gary W., 2024, Australasian Lophothamnion J. Agardh aligns genetically with Pleonosporium Nägeli (Wrangeliaceae, Spongoclonieae): new species from the western Atlantic, Cryptogamie, Algologie 20 (1), pp. 1-10 : 4

Pleonosporium novae-angliae G.W.Saunders & C.W.Schneider , sp. nov.

( Fig. 2 )

HOLOTYPE (DESIGNATED HERE). — United States. Rhode Island, Fort Wetherill , 41°28’44.8”N, 71°21’36.2”W, subtidal (6 m) on other algae, 10.VIII.2007, G.W. Saunders & B. Clarkston, GWS005733 (holo-, UNB), GenBank: OQ561797 (COI-5P), OQ561894 (rbc L), OQ561850 (SSU).

PARATYPE. — United States. Massachusetts, Woods Hole , Garbage Beach Breakwater, 41°31’30.7”N, 70°40’21.2”W, subtidal (3 m) on Sargassum C.Agardh , 14.IV.2010, B. Clarkston, D. McDevit, M. Bruce, A. Savoie & C. Longtin, GWS017847 (para-, UNB), GenBank: OR336111 (rbc L-3P).

ADDITIONAL MATERIAL STUDIED. — United States. Massachusetts, Martha’s Vineyard, Edgartown, 5.VII.1897, M. Jernegan, P. B.- A. 342b (Herb. CWS); Connecticut, Bridgeport, Black Rock Beach (Seabright Beach), 26.VIII.1894, I. Holden 1031 (Herb. CWS); Fairfield , Penfield Reef, 19.VII.1896, I. Holden 1203 (Herb. CWS); Penfield Reef near Bridgeport, VII-VIII.1897, I. Holden, P. B.- A. 342a (Herb. CWS); Waterford, Millstone Point, Fox Island South, 12.X.1976, C. Schneider 1310 (Herb. CWS); Waterford , Goshen Point, 5.XI.1977, C. Schneider 1874 (Herb. CWS); Groton, Bluff Point State Park , 12.IX.1978, C. Schneider 78-16-3 (Herb. CWS) .

ETYMOLOGY. — Novae-angliae (Latin, genitive), for “of New England ”, its present distribution in northeastern North America.

DISTRIBUTION. — From southern Cape Cod , Massachusetts to Connecticut and New York in Long Island Sound, United States.

DESCRIPTION

Plants epiphytic, bushy, erect to 2-6 cm tall ( Fig.2A ), Redwood red (Graf 1x 2023) to purplish-red in colour, attached by basal cells and rhizoids;relatively common descending rhizoids simple or branched and variously adherent to, or free of, main axes and typically produced from basal cells of branches ( Fig. 2B ); axes throughout uniseriate and essentially ecorticate, indeterminate axes with slightly overtopping branches in a weak sigmoidal pattern, branching regularly alternate in a single plane in upper portions, appearing pyramidal in outline ( Fig. 2C ); upper axial cells of indeterminate axes 16-20 µm diam. and 18-25 µm long, middle portions with relatively regular and alternate (slightly spiralled) branches, mid-axial cells prominent, 35-50 µm diam. and 112-154 µm long; indeterminate axial cells in lower portions 125-260 µm diam. and 550-860 µm long, the axes held together by a tangle of free rhizoids; non-sequenced plants with tetrasporangia and octosporangia adaxially sessile on upper branches ( Fig. 2D, E ), borne singly or on a series of successive cells ( Fig. 2F ); subglobose to obovoidal, 35-50 µm diam.and 50-60 µm long, including a thick wall; spermatangia in oblong masses ( Taylor 1957), cystocarps unknown.

Figures

FIG. 2. — Pleonosporium novae-angliae G.W.Saunders & C.W.Schneider, sp. nov., holotype specimen (GWS005733): A, habit of type specimen; B, origins of rhizoids (arrowheads) that will eventually loosely envelop proximal axial cells (CWS 78-16-3); C, apices of axes and branches with distichous, triangular pat- terns (CWS 1310); D, tetrasporangium (CWS 78-16-3); E, octosporangium (CWS 78-16-3); F, adaxial tetrasporangium (arrowhead) and octosporangium (double arrowheads) developing singly and in a series on upper lateral branches (CWS 78-16-3). Scale bars: A, 2 cm; B, C, 250 µm; D-F, 50 µm.