Volume 10, Part 1, February 1996

THE RARE AND FASCINATING DEVIL'S CIGAR,CHORIOACTIS GEASTER

K.C. RUDY & *HAROLD W. KELLER

River Legacy Foundation, PO. Box 150392, Arlington, Texas, USA 76015* Botanical Research Institute of Texas, 509 Pecan Street, Fort Worth, Texas,

USA 76102-4060 e-mail: keller@hsc.unt.edu

Chorioactis geaster, a rare species with a very unusual distribution is described and highlighted .Its recently discovered abundance in a large city park in Arlington, Texas, USA is detailed.

Keywords: ascomycete, apothecium, dehiscence, disjunct, distribution, hymenial surface,monotypic, operculate, paraphyses.

On 23 September 1991, volunteer trail guideMary Jones noticed an unusual, three-inch fun-gus adjacent to an unpaved nature trail in RiverLegacy Parks, Arlington (Tarrant County), Texas.It was immediately determined to be quite dif-ferent from any other fungus seen previously inthe area, and Professor Donald Pfister of theFarlow Herbarium of Cryptogamic Botany atHarvard University identified it as Chorioactisge as ter (Peck.) Eckblad (fo rmerly Urnulageaster Peck), an operculate fungus in theSarco somataceae. Information regarding thisspecies is scarce and it has been reported fromonly Texas and Japan.

According to Seaver (1937), this fungus wasoriginally reported in 1893 from the Austin,Texas area. It was subsequently reported fromJapan from a single specimen by Imazeki (1938)and again in the Austin area by Seaver (1939).Interestingly, 38 years elapsed before C. geastercould again be located in Japan (Imazeki &Otani, 1975). It has apparently been located inthe Denton, Texas area, since a passing refer-ence was made to it in this regard by Buller(1934). We also discovered it growing in HuntCounty, Texas in 1991, and it has recently beenreported growing near Joe Pool Lake in south-western Dallas County, Texas (Rice, 1995).Despite being referred to as 'fairly common inTexas' by Arora (1986), it seems to have beenreported only from the Austin and north centralTexas areas.

In addition to the oddly disjunct and restrict-ed distribution of this sizable fungus, there areother features making the genus particularlyunusual. The apothecium, which is dark brown,

tough, and leathery, shows up in the fall as a hol-low, spindle-shaped tube and lasts until a hardfreeze. As it matures (Fig1), growing to as muchas four inches in height, it splits open from the

Fig. 1 The Devil's Cigar, Chorioactis geaster, emerging in the fall inclose proximity to a decaying cedar elm stump. A quarter, 1 inch (2.5em) in diameter, is shown for a sense of scale. Photo : K.C. Rudy.

Fig. 2 Hymenial surface of a fully opened Devil's Cigar.Photo : KC. Rudy.

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Volume 10, Part 1, February 1996

apex into three to six rays (see front cover plate),forming a sizable earth star reminiscent ofGeastrum spp. This exposes the bright butter-scotch-yellow coloured hymenial surface (Fig 2),the morphological feature largely responsible forits former inclusion in the Sarcoscyphaceae(Otani, 1980). Dehiscence results from pressureproduced by swelling of the cells in the paraphy-ses (Pfister, 1978), and this triggers the release ofa cloud of spores in the process. According toWolf (1958), this process is comprised of a pres-sure buildup due to an increase in osmotic con-centration, occurring in conjunction with theactivation of the glycolytic enzyme system byheat absorbed by melanin in the outer apothecialwall. Seaver (1937) provides a detailed descrip-tion of this process.

Particularly fascinating is the fact that thisspore release is accompanied by an audible hiss.Having heard this several times in the field, wecan attest to the fact that the sound can be easi-ly heard from a distance of several feet. Also,this spore release occurs both upon dehiscenceand intermittently thereafter; this latter fact isapparently heretofore unrecorded. The substan-tial cloud of spores released by this 'explodingfungus' is the primary reason for its commonname, the Devil's Cigar. At the time of Wolf(1958), this split-release phenomenon was knownto occur only in Urnula craterium (Schw.) Friesand U. geaster (now Chorioactis geaster). Buller(1934) reports 14 other fungal species that pro-duce an audible hiss upon spore release. Theaudible spore release of the Devil's Cigar, as wellas for other fungi, and its disjunct geographic dis-tribution are discussed by Wolf& Wolf (1947).

Kupfer (1902), after examination of internal aswell as external characteristics, recognized sub-stantial differences between Urnula crateriumand U. geaster, as it was called then, and pro-posed a new generic name: Chorioactis (from theGreek chori-, meaning separate and actino-,meaning starlike). However, it generally contin-ued to be referred to under Urnula until furthersupport for Chorioactis came from Eckblad(1968), who re-evaluated the taxonomy, phyloge-ny, and nomenclature of the operculate dis-comycetes.

The area from which C. geaster is being newlyreported can be characterized as mesic, riparian,hardwood forest. The site occurs in RiverLegacy Parks, Arlington, Texas, and within 100

to 300 yards of the West Fork of the TrinityRiver in Tarrant County, Texas. Tree speciesdominant in the area include cedar elm (Ulmuscrassi/olia), sugar hackberry (Celtis laevigata),bur oak (Quercus macrocarpa), green ash(Fraxinus pennsylvanica), and gum bumelia(Bumelia lanuginosa). The soil is sandy and thearea is flooded about once per year.

The original specimens from the Austin,Texas area were reported growing attached tocedar elm 'sticks' on the ground (Seaver, 1928).The Japanese specimens were reported growingin association with fallen trunks of Symplocosmyrtacea and Quercus gilba. Smith, et al. (1981)also report C. geaster growing on fallen sticks;however, in Dallas and Tarrant Counties it isapparently exclusively associated with decayinghardwood stumps known or thought to be cedarelm. This is supported by Buller (1934), althoughSeaver (1942), in a delightful reprinting of corre-spondence between G.W. Goldsmith of theUniversity of Texas and himself, reports theassociation extending to oak roots as well. Thehost stumps are generally decayed to the pointwhere both the bark and the centre of the stumpare virtually gone, making positive identificationvery difficult. Examination of the substraterevealed that sclerotia were lacking and that theascomata arise directly from remaining stumpwood and radiating roots near the surface, bothof which are relatively hard.

The scarcity of this fungus in nature is almostmatched by the rarity of references in taxonomickeys, literature, and textbooks. In addition tothe foregoing references, it was described in aDutch journal by Samson & Jackson (1977) asone of three very unusual Texas species. It alsooccasionally turns up pictorially in publicationssuch as Texas Highways magazine (e.g.,Weisman, 1991), often unidentified or with littlediscussion.

Why is the Devil's Cigar so seldom encoun-tered? Does it have a very specific set of survivalconditions related to substrate, moisture andgeneral climate? One would have to assume, dueprimarily to its size, that it is not going unno-ticed.

References:Arora, D. (1986) Mushrooms Demystiiied (2nd ed.). Ten

Speed Press, Berkeley, California.Buller, A.H.R. (1934) Researches on Fungi (Vol VI)

Reprinted 1958. Hafner Publ., New York.

Eckblad , F.-E. (1968) T he genera of the ope rcula teDiscomycetes: a re-evaluation of their taxonomy, phy-logeny and nomenclature. Nyu Magasin for Botanik15: 1-191.

Imazeki, R (1938) A rare fungus, Urnula geaster Peckgrows in Kyusyu, Japan. Journal of Japanese Botany14: 680-684.

Imazeki, R & Otani, Y. (1975)Rediscovery of Chorioactisgeaster (Peck) E ckblad in Kyu syu , J apan.Transactions of the Mycological Society of Japan16: 222-229.

Kupfer, E.M. (1902) Studies on Urnula and Geopyxis.Bulletin of the Torrey Botanical Club 29: 137-144.

Otani, Y. (1980) Sarcoscyphineae of Japan. Transactionsof the MycologicalSociety of Japan 21: 149-179.

Pfister , D.H. (1978) Apothecial development in Cookeinatricholoma with comments on some related species.Mycologia 70: 1253-1257.

Rice, K.A. (1995) Personal Communication.Sa mso n, RA. & Jackson , RE. (1977) Mycologische

Volume 10, Part 1, February 1996

Waarnemingen in Texas. Coolia 20: 38-43.Se ave r, F.J . (1928) Th e No rth A merican Cup -fungi

(Operculates). [published by the author], New York.Seaver, F.J. (1937) Photographs and descriptions of cup-

fungi-XXV. Urnula geaster. Mycologia 29: 60-65.Seaver, F.J. (1939) Urnula geaster (in Notes and Brief

Articles). Mycologia 31: 367-368.Seaver, F.J . (1942) Th e No rth American Cup- fungi

(Operculates) - (Suppleme nt). [Publish ed by theauthor], New York.

Smith, A., Smith, H. & Weber, N. (1981) How to Knowthe Non-gilled Mushrooms (2nd ed.). Wm. C. BrownPubl., Dubuque , Iowa. 324 pp.

Weisman, D. (1991) Austin' s heart of gre en. TexasHighways 38: 2-9.

Wolf, FA & Wolf, F.T. (1947) The Fungi (Vol. II). JohnWiley & Sons, Inc., New York.

Wolf, FA (1958) Mechanism of apothecial opening andascospore expulsion by the cup-fungus Urnula crateri-um. Mycologic 50: 837-843.

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