**4.2. Morphological characters of asexual morph.**

The asexual morph of ascomycetous bambusicolous fungi is coelomycetous or hyphomyceteous [45–48], as in the asexual morph of *Bambusicola* and *Apiospora* Sacc. (≡*Arthrinium* Kunze)

*4.1.2. Asci*

170 Bamboo - Current and Future Prospects

*4.1.3. Ascospores.*

verrucose, or covered by a sheath.

**4.2. Morphological characters of asexual morph.**

The morphology of asci is particularly of two major types, unitunicate and bitunicate (**Figure 6**). Asci are produced within the ascomata and act as platforms from which the spores are launched. However, some asci release the ascospores passively by dissolving the ascal wall at maturity, rather than active spore-shooting mechanism. Asci usually bear eight ascospores, though sometimes with four or six, and occasionally producing multiple numbers of ascospores.

**Figure 4.** Ascomata on different bamboo substrates. (a), (b) on bamboo leaves. (c) on bamboo sheath.(d) on bamboo culm.

The ascospores of bambusicolous fungi exhibit a variety of shapes (**Figure 7**). The common shapes are ellipsoidal, fusiform, filiform, and so on. The color of ascospores can be hyaline, pale brown, brown to dark brown. The ascospores usually are single-celled or have one to two septa and sometimes multiseptate, like muriform spores. Their surfaces are smooth, striate to

The asexual morph of ascomycetous bambusicolous fungi is coelomycetous or hyphomyceteous [45–48], as in the asexual morph of *Bambusicola* and *Apiospora* Sacc. (≡*Arthrinium* Kunze)

**Figure 5.** Various types of ascomata on bamboo. a–g, l: superficial ascomata; h–j: erupted ascomata; k: immersed ascomata; a–c, e, h: perithecia; d: stromata; f, g: flatten ascostromata; i: multiloculate stroma; j: conical stromatic ascomata; k: stromata; l: *xylarioid* stromata.

[16, 45]. The major morphologic characters are conidiomata, conidiophores, and conidiogenous cells. In the coelomycetous fungi, the conidia develop in a growing cavity, called conidiomata which can be acervuli, pycnidia, or sporodochium-like structures [64]. For hyphomycetous fungi, a conidium develops directly on the conidiophores which may be mononematous or synnematous and bear a single or more conidiogenous cells which usually are holoblastic, enteroblastic, phialidic, annelidic, or tretic. Conidium ontogeny has long been used as an

**Figure 6.** Asci types. a, b, c, h: bitunicate asci (note in b, jack-in-a-box spore release mechanism). d, e: unitunicate asci; f: unitunicate ascus with a special elastic ring at the tip; g: unitunicate asci with a flat apex; h: bitunicate ascus with a long narrow basal portion; i: fissitunicate asci.

**5. Bamboo ascomycetes taxonomic distribution**

m: filiform ascospores.

The ascomycetes on bamboo are very diverse, together with their asexual morphs. In [30], the author recorded 460 species belonging to 218 genera in 43 families from all over the world. A reference [3] reported 630 species distributed in 121 families and 436 genera within ascomycota. According to our investigation on the basis of the current references, 800 ascomycetous

**Figure 7.** Ascospores types. a, e: ascospores surrounded by a sheath; b: striate ascospore; c, k: verrucose ascospores; d: dark brown, 6-septate ascospore; f, i, j: fusiform ascospores; g: muriform ascospore; h: smooth-walled ascospore; l,

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species (**Figure 8**) belonging to 465 genera within 128 families were documented.

important taxonomic feature in the diagnosis of conidial fungi [65]. Mostly, the conidiophores of coelomycetous fungi are reduced to conidiogenous cells, when they grow on the host substrate. However, some of them remain hyphomycetous (producing free conidiophores) on culture, as in *Arthrinium* [51].

**Figure 7.** Ascospores types. a, e: ascospores surrounded by a sheath; b: striate ascospore; c, k: verrucose ascospores; d: dark brown, 6-septate ascospore; f, i, j: fusiform ascospores; g: muriform ascospore; h: smooth-walled ascospore; l, m: filiform ascospores.
