Termitomyces microcarpus (Berk. & Broome) R. Heim (Mém. Acad. Sci. Inst. Fr. 64: 72, 1941) – large form
Description. Medium-sized fleshy agaric with whitish cap, acute umbo, whitish gills and small to long central stipe without pseudorhiza. Gregarious or in large troops in soil, rare, odour pleasant, taste excellent, edible. Pileus (2.0)2.4–4.4(5.1) cm diam., at first campanulate becoming expanded or convex with a small, acute, papillate umbo and irregularly lobed margin; at first whitish fading to whitish grey / smoky grey, smooth to silky, radially striate and viscid or slimy when wet, otherwise dry; context of pileus smoky white, moderately thick and fleshy. Lamellae white, free to adnexed, broad, sparsely crowded, regular; short gills of 2−3 lengths. Stipe (2.7)2.8–5.7(7.6) × (0.15)0.2–0.35(0.4) cm, central, cylindrical, small to long, slender, slightly tapering towards the apex and without pseudorhiza; whitish, fibrillose, smooth and solid. Annulus absent. Basidiospores (5.9)6.0–6.6(6.8) × (3.4)3.7–3.9(4.2) μm, broadly ellipsoidal, hyaline and smooth.
Termitomyces microcarpus is closely related to T. medius in shape of pileus as well as umbo, but T. microcarpus differs for being devoid of pseudorhiza.
Substrate and distribution. On soil associated with termite faecal pellets in low elevation shola forest (Sampaje), sacred grove (Kottoli), evergreen forest (Bramhagiri wild life sanctuary), and deciduous forest (Dubare), Kodagu.
N o t e s. From the African region, Frøslev (on-line) and De Kesel (2011) have documented the pileus diameter of T. microcarpus being ≤ 2 cm, while Pegler & Vanhaecke (1994) from Southeast Asia, and Tibuhwa (2012b) from Tanzania, con- sidered the pileus diameter to be < 3 cm. The specimen from the Western Ghats in our study showed an average pileus diameter > 3 cm (average 3.4 cm; range 2.0–5.1 cm) and an average stipe length of 5 cm (range 2.7–7.6 cm). The measure- ment was taken from a troop consisting of approximately 3,500 individuals, visu- ally considering small and large individuals. The authors also observed such varia- tion in pileus and stipe measurements between particular locations in the Kodagu region. It is assumed that geographical difference, environmental conditions (es- pecially soil edaphic features) and species of termite involved in cultivation have a major influence on the dimension of the mushrooms.
Based on the smallest pileus diameter (< 2 cm) as seen in the African region (Frøslev on-line, De Kesel 2011), as well as the length of the stipe (1.3–2.3 cm) of T. microcarpus in our study, there seems to exist another forma in T. micro- carpus. Thus, we have considered describing the features of large and small forms of T. microcarpus separately. Details of the small form of T. microcarpus are given in the following section.
Termitomyces microcarpus – small form
Description. Small fleshy agaric with pinkish white cap, papillate umbo, pale pinkish gills and slender central stipe without pseudorhiza. Gregarious or in small to large troops on faecal pellets of termites in soil, frequent, odour pleasant, taste excellent, edible. Pileus (0.9)1.1–1.2(1.3) cm diam., at first campanulate be- coming plano-convex to upturned with a small papillate umbo and irregularly lobed margin; at first whitish turning to pinkish-white or cream-white, smooth, silky to fibrillose, shiny and dry; context of pileus white, thin and fleshy. Lamellae pale pinkish, free to adnexed, sparsely crowded, regular; short gills of 2–3 lengths. Stipe (1.3)1.7–2.1(2.3) × (0.15)0.2–0.25 cm, central, cylindrical, slender; bulbous base attached to faecal pellets of termites; whitish, solid and fibrous. Annulus ab- sent. Basidiospores (4.6)5.0–5.5(5.8) × (2.6)2.9–3.7(4.0) μm, broadly ellipsoidal, hyaline and smooth.
Although this form of T. microcarpus closely resembles T. microcarpus (large form) especially in lacking pseudorhiza, it differs in having a small pinkish-white pileus and papillate umbo, and fruitbodies emerge directly from termite faecal pellets.
Substrate and distribution. Directly emerging from faecal pellets of termites in coffee agroforest (B’Shettigeri), grasslands, golf fields (Madikeri), and playgrounds (Virajpet), Kodagu.
N o t e s: Similar to our study, this small form (as T. microcarpus f. microcarpus) was mentioned by Tibuhwa et al. (2010) while considering micro- and macro-mor- phological characteristics of 25 species of Termitomyces for classification. Simi- larly, another forma (small form without true umbo) has been reported from the south-west region of the Western Ghats of India by Mohanan (2011). This forma emerges exclusively from termite faecal pellets deposited on leaf litter. In addition to T. microcarpus (small form, known as Katolakum or Akkikum in local language) explained above, there is one more forma (also small, known as Kokkalaekum), which is extensively consumed by tribal communities in the Kodagu region of the Western Ghats (Gowda, Kodava, Kuruba, Kudiya, and Yarava). This one resembles T. microcarpus f. microcarpus reported by Mohanan (2011).