Dianema harveyi Rex (1891: 397)

Ronikier, Anna, 2023, Typification of the name Dianema harveyi (Dianemataceae), Phytotaxa 620 (4), pp. 293-300 : 297-299

Dianema harveyi Rex (1891: 397)

Original species description ( Rex 1891): —Sporangia sessile, generally rounded or cushion-shaped, flattened above, averaging about 1 mm in diameter, 0.35 mm in height, sometimes elongated and bent into an irregular horse-shoeshape, color gold bronze, with a metallic lustre. Sporangium walls membranaceous, thin, translucent, containing no trace of lime, rupturing irregularly. Capillitium and spores concolorous, being brownish-yellow in mass. Capillitium composed of numerous slender threads from 1.5 to 2 µm in diameter, not connected with each other, simple, without free branches but often forked two or three times near their origin or insertion, nearly parallel, taut, running from base to the top of the sporangium. Spores 8 µm in diameter, pale yellow under a microscope, delicately spinulose, but apparently smooth under medium power lenses.

Orono, Maine, F. L. Harvey .

Lectotype (designated here, MBT 10015616): —Orono, Maine, F. B. Harvey #23 b, 1890, 1042662!, barcode PH00002637 ( Fig. 1A–G , 3 ).

Other original material (syntypes): Maine?, surely part of type sent to Morgan by Wingate , BPI746312 ! ( Fig. 1I –J , 4 ); Maine, leg. F. L. Harvey, det. G.A. Rex —from Wingate coll., BPI746311 ! ( Fig. 2A–C , 5 ); Maine, leg. F. L. Harvey, det. G.A. Rex —from Wingate coll., ex Univ. Iowa Myxomycete Collection, BPI746310 ! ( Fig. 2 D – E , 6 ); Orono, Maine, leg. F. L. Harvey, L:B.M.168 ( Fig. 1H ) .

Description of Dianema harveyi based on examined collections: —Sporophores scattered, sessile on a broad base, pulvinate, flattened above, copper-brown, effuse sporocarps or short plasmodiocarps, 0.70–1.36 mm long, 0.50– 1.3 mm wide and 0.20–0.46 mm high ( Figs. 3A–B , 4A ). Peridium slightly iridescent, single, dehiscing irregularly, the inner side slightly rough as seen by SEM ( Figs. 3C , 4B ). Capillitium rusty-yellow, not dense, straight, rigid, built up of parallel and dichotomously branched threads connecting the base of sporotheca and peridium, capillitial threads firmly attached to the peridium, smooth or rough ( Figs. 3C–F , 4B–E ). Spores rusty-yellow in mass, free, globose, very pale yellow as seen by compound microscope, 8–9.5 µm, av. 8.72µm, covered by irregularly distributed spines, baculate as seen by SEM, baculae with uneven apices, irregularly distributed ( Figs. 3G , 4F ).

Conclusions:— Among five syntypes of Dianema harveyi found at PH, BPI and BM, two were revised to represent that species, two others turned out to be a similar species, Prototrichia metallica and one (dry mount) has not been verified. The specimen stored at PH has been here designated for a lectotype of D. harveyi . This species differs from P. metallica by its flattened sporocarps, and completely smooth capillitium. Typically P. metallica has very characteristic penicillate capillitium with threads covered by spirals that are easy to observe under compound microscope. Importantly, the results of this study revealed that the characters of capillitium of P. metallica may sometimes be weakly developed; hence some specimens of P. metallica can be easily confused with D. harveyi . This is especially important in the light of the recently recognized very close phylogenetic relationships between these two species ( Ronikier et al. 2020; García-Cunchillos et al. 2022). Therefore, a careful examination of capillitium characters together with shape of sporocarps is necessary to differentiate poorly developed sporophores of P. metallica from those of D. harveyi .

Figures

FIGURE 1. Syntypes of Dianema harveyi Rex revised to represent D. harveyi. A–G. Specimen PH00002637 (Lectotypus).A. Herbarium envelope of the collection PH00002637. B–C. Inside annotation labels of the collection PH00002637. D. Inner side of a small box containing the collection PH00002367 with visible handwritten information and three sporophores—note one in a shape of a horse-shoe (arrow). E. Barcode of the collection PH00002367. F. Upper cover (lid) of the small box containing the specimen PH00002367. G. Lower cover (bottom) of the small box containing the specimen PH00002367. H. A dry mount of Dianema harveyi kept in BM as a permanent slide no. L:B.M.168 (photo: Gothamie Weerakoon). I–J. Specimen BPI746312. I. Herbarium label of the collection BPI 746312. J. Collection BPI 746312 with two labels glued to the bottom and a group of sporophores.

FIGURE 2. Syntypes of Dianema harveyi Rex revised to represent Prototrichia metallica (Berk.) Massee.A–C. Specimen BPI746311.A. Herbarium label of the collection BPI746311. B. Collection BPI746311 with visible group of sporophores (right) and remnants of single sporophores (arrows). C. Handwritten inside label of the collection BPI 746311. D–E. Specimen BPI746310. D. Herbarium label of the collection BPI 746310. E. Collection BPI 746310 with visible small groups of sporophores glued to the box bottom.

FIGURE 3. Lectotype of Dianema harveyi Rex (PH00002637).A. Two sporophores. B.A sporophore in a shape of a horse-shoe. C. Inner surface of peridium (SEM) with places of capillitium attachment. D–F. Capillitial threads (SEM). G. Spore (SEM). Scale bars: A–B = 1 mm, C = 20 µm, D–G = 10 µm.

FIGURE 4. Syntype of Dianema harveyi Rex revised to represent D. harveyi (BPI 746312). A. Group of flattened sporophores. B Inner surface of peridium (SEM) with places of capillitium attachment. C–E. Capillitial threads (SEM). F. Spores (SEM). Scale bars:A = 1 mm, B = 20 µm, C = 100 μm, D–F = 10 µm.

FIGURE 5. Syntype of Dianema harveyi Rex revised to represent Prototrichia metallica (Berk.) Massee. (BPI 746311). A. Group of sporophores (photo: Krzysztof Stachowicz). B. A sporophore (photo: Krzysztof Stachowicz). C. Inner rough peridium surface (SEM). D–F. Capillitial threads with visible spirals (SEM). G. Spores (SEM). Scale bars: A–B = 1 mm, C = 20 µm, D = 30 μm, E = 50 µm, F–G = 10μm.

FIGURE 6. Syntype of Dianema harveyi Rex revised to represent Prototrichia metallica (Berk.) Massee. (BPI 746310). A. Sporophore (photo: Krzysztof Stachowicz). B. Open sporophore with vissible penicillate capillitium (photo: Krzysztof Stachowicz). C–E. Capillitial threads with visible spirals (SEM). F. Spores (SEM). Scale bars:A–B = 1 mm, C = 100 µm, D, F = 10 μm, E = 30 µm.