Asterina rubiacearum M.R. Bhise, C.R. Patil, C.B. Salunkhe & S.V. Kambhar, 2021

Bhise, Mahendra R., Patil, Chandrahas R., Salunkhe, Chandrakant B. & Kambhar, Sidanand V., 2021, New species of Asterina and Balladyna (black mildew fungi) from Mahabaleshwar, Maharashtra, India, Phytotaxa 511 (3), pp. 283-288 : 284

Asterina rubiacearum M.R. Bhise, C.R. Patil, C.B. Salunkhe & S.V. Kambhar sp. nov. ( Fig. 1 ) MycoBank: MB 811797.

Colonies amphigenous, dark black, circular to spreading, dense to sparse, confluent, up to 9 mm diameter, forming dark brown blotches below the colony. Hyphae dark brown, straight to undulate, branching opposite to alternate, mostly alternate at wide angles, loosely reticulate. Hyphal cells 24–32 × 7 μm. Appressoria alternate to unilateral, moderately placed, unicellular, subglobose to shallowly lobed, margin rough, 6–12 × 7–14 μm. Thyriothecia scattered on mycelium, globose to orbicular, stellately dehisced at the center, margin fimbriate with fringed hyphae, up to 238 μm diameter. Asci numerous, initially globose, ovate at maturity, 8-spored, 47–55 × 32–41 μm. Ascospores oblong, conglobate, olivaceous brown, uniseptate, deeply constricted at the septum, upper cell obovate, lower globose, 31–38 × 14–19 μm, wall smooth.

Type:— INDIA. Maharashtra: Satara, Mahabaleshwar, Machutar-Tetawali , on leaves of Canthium dicoccum var. umbellatum (Wight) Sant. & Merch. (Rubiaceae) , 11 December 2013, Bhise M.R., MHB0406 (b), holotype ( HCIO 51666 ) .

Additional specimens examined:— INDIA. Maharashtra: Satara, Mahabaleshwar, Linghmala , on leaves of Canthium dicoccum var. umbellatum , 22 December 2012, Bhise M.R., MHB0071, HCIO 51665 ; Kharoshi , Mahabaleshwar, 7 February 2014, Bhise M.R., MHB0532, HCIO 51667 .

Etymology:— the specific epithet refers to the host plant family Rubiaceae .

Notes:— Asterina canthiigena Hosag., Archana & Agarwal and A. canthii-dicocci Hosag. are known on Canthium sp. from Karnataka, India, but are not reported from elsewhere ( Hosagoudar 2012). Asterina rubiacearum differs from these two species and closely related species in having larger size colonies, forming dark brown blotches below the colony; single-celled and smaller appressoria, and larger thyriothecia, asci and ascospores ( Table 1 ). Hence, A. rubiacearum is proposed as a new species.

Asterina rubiacearum is associated with Balladyna canthiigena sp. nov., Meliola longiseta Höhnel and M. plectroniae Hansf. , which are also growing on the leaves.

Figures

FIGURE 1. Illustration of Asterina rubiacearum M.R. Bhise, C.R. Patil, C.B. Salunkhe & S.V. Kambhar. (A) Infected Leaf, (B) Mycelial Colony with thyriothecia, (C) & (G) Appressoriate mycelium, (D) & (H) Part of thyriothecium, (E) & (I) Ascus, (F) & (J) Ascospores. Illustrated by Mahendra R. Bhise