Ocellularia rhodostroma (Mont.) Zahlbr.

Ocellularia rhodostroma

Ocellularia rhodostroma (Montagne) Zahlbruckner, 1923:600.

Ascidium rhodostromum Montagne, 1851:75 [type-collection: Cayenne, French Guiana, collection 1334 (P, lectotype); Figure 13a].

Thallus light greenish tan to gray, smooth to finely warty, continuous and epiphloeodal, the medulla white or pink, forming colonies 5–10 cm

broad; apothecia large and easily visible with the naked eye, ascidioid, 1.0–1.8 mm in diameter, the walls heavily carbonized and the medulla deep pink, readily exposed as the fragile cortex breaks away, columella lacking; pore round and small, 0.05–0.1 mm in diameter, surrounded by a raised ring; hymenium 200μ–275μ high; spores 1–2/ascus, 25–30 loculate, 25μ–40μ × 100μ–250μ, I+ blue (Figures 5g and 7b).

CHEMISTRY.—Hypoprotocetraric acid and in greater concentration 4–0–demethylnotatic acid along with unidentified pigments.

HABITAT.—Canopy branches to lower bole at all elevations on the island.

Ocellularia rhodostroma is the commonest thelotreme on Dominica and the easiest to identify as well. The large ascidioid apothecia have a deep pink medulla exposed when the fragile cortex breaks. The pore is strongly annulate. While occurring at all elevations, it seems best developed at higher elevation into the mossy forest, perhaps because it competes with so few other species there.

SPECIMENS EXAMINED.—7 (35246), 8 (38122, 38146, 38166), 10 (38119), 11 (37815, 37823, 37824, 38004, 38023, 38049), 12 (37894, 37916, 37917, 37927, 37930, 37934), 13 (35279 35448), 14 (35111, 35133), 15 (35160, 35170, 35188, 35314, 16a (37653, 37938), 16b (37800, 37806, 37875, 37994, 37995), 16c (37756, 37870, 37979), 18a (37729, 37731, 37987), 18b (35517, 35522, 35523, 35587), 20a (37777, 38065), 21 (38035, 38147), 22 (37641, 37643, 37650, 37835, 37861), 23 (37672, 38975), 24a (37736, 37742, 37745, 37749, 37754, 38068), 24b (35629), 25a (37705, 37707, 37720, 37840, 37846, 37848, 37862, 37867, 37971, 37975), 25b (35469), 26a (37689, 37690, 37693, 37694, 37699, 37703, 37864, 37866, 37885, 37947 38000, 38014), 26b (35354, 35366, 35371, 35372, 35376), 27 (37831), 28 (35435, 35440).