Public Description of Comatricha Preuss

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Name: Comatricha Preuss
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 Draft For 2008/2009 Eol University Species Pages Initiative By Jason Liu (Private)

Description status: Unreviewed

Taxonomic Classification:

Kingdom: Protozoa
Phylum: Mycetozoa
Class: Myxogastrea
Order: Stemonitida
Family: Stemonitidaceae

General Description:

The full lineage of the genus Comatricha is domain Eukaryota; kingdom Amoebozoa; phylum Mycetozoa; class Myxogastria; order Stemonitida; and family Stemonitidae10. Being in the phylum Mycetozoa designates the genus Comatricha as a plasmodial slime mold; its life cycle is depicted here Plasmodial Slime Mold Life Cycle 9. The type taxon for Comatricha is Comatricha obtusata (Fr. & Palmquist) Preuss 5. Comatricha contains species that develop stalked sporangia fruiting bodies. These can be spherical or cylindrical sporangia. The sporangia can be scattered and clustered or fully packed. The stalks are often at the minimum, half the total height of the sporangia. The stalks can be made of intertwined fibers or be hollow2. Comatricha has a fugacious peridium which leaves flakes or a collar around the stalk of the sporangia. In other words, there is no surface net on the fruiting body of this genus. Columella is another name for the stalk of the sporangia. Typically, the columella reaches near the top of the sporangia. The columella gives rise to the capillitium of thread-like tubules which hold spores. The capillitium branches off the columella through anastomosis to form an internal net. Often, the capillitium has fragmented loops or free ends on the surface. The spores of Comatricha are like iron dust which appear black or purple. When the spores are seen by transmitted light, they can appear violaceous to pale. The spores give the sporangia its color1.

Synonymes of Comatricha include Collaria Nann.-Brem. 1967, Comatrichiodes Hertel 195, Paradiachea Hertel 1956, and Raciborskia Berl. 18885.

Diagnostic Description:

The genus Comatricha is very similar to the genus Stemonitis. Despite their similarity, one way they can be distinguished from each other is by surface net characteristics. Even in the species within the genus Comatricha which develop capillitium that are extensively anastomosed near the surface of the sporangia (Comatricha typhoides and Comatricha laxa), there is no surface net. On the other hand, a surface net is almost always present in Stemonitis sporangia1.

This is a book except from Martin, Alexopoulos, Farr (1983). It includes an original description for separating genus Comatricha from close relatives as well as subsequent modifications of it1:

“Even in such species as Comatricha typhoides and C. laxa, where the capillitium is extensively branched and anastomosed near the surface, the lack of a surface net is apparent, whereas it is nearly always present in Stemonitis sporangia, at least in the lower portion, and to a greater extent than the descriptions imply in those species in which it is said to be lacking above. In S. hyperopta, for example, there are often traces of delicate net in the upper part of the sporangium, although the net falls away more quickly than in other species.

Ross (1958b) showed that, in three species of Stemonitis, the capillitium developed both from the columella and from areas within the sporogenous mass and that the net developed just under the surface from loci within the peripheral protoplasm, while in Comatricha typhoides the entire capillitial system arose from the columella. Goodwin (1961) studied three additional species of Comatricha and found that they developed as described by Ross for C. typhoides. This suggests that the presence or absence of a net may be of fundamental significance.

Alexopoulos (1967) stressed the importance of stalk characters in these genera; stalks of Stemonitis and Macbrideola typically are hollow, tubular, and homogenous, while those of Comatricha are filled with an interlaced mass of threadlike strands. Partly on that basis he transferred three of the minute species of Comatricha to Macbrideola.

Hertel (1956) earlier suggested extensive revision of Comatricha, proposing several new genera. His work was reviewed and amplified by Nannenga-Bremekamp (1967). The latter author recognized Paradiachea Hertel essentially as it was originally proposed, to include those species with a persistent peridium. In view of the quantitaive variation of this character among and even within species (Comatricha typhoides, for example), this separation appears superfluous. Nannenga-Bremekamp (1967, 1974) also accepted and substantially modified Paradiacheopsis Hertel, transferring several additional species to that genus, and distributed the residual species of Comatricha among four subgenera: Comatricha, Laxaria Nann.-Brem., Sinuaria Nann.-Brem., and Stemonitopsis Nann.-Brem. The last name was rasied to generic rank in her book (1974) and typified by Stemonitis hyperopta."

This is a book excerpt from Macbride (1922). If offers more history regarding the origin of the genus Comatricha11:

“Sporangia cylindric or globose, stipitate; stipe prolonged upward to form more or less extended and tapering columella bearing branches on every side, which by repeated divisions and reunions form the capillitium; ultimate branch-tips free, not supporting a surface net parallel to the peridial wall; peridium evanescent, perhaps sometimes not developed at all.

The genus Comatricha was set off from Stemonitis by the joint effort of Preuss (1851) and Rostafinski (1873-5). Preuss included in his genus, Comatricha, alien forms, and besides failed to give an accurate definition; included, however, in his list some species which have since been known by his generic name.

The distinction between the two genera is almost an artificial one, and species are sometimes arbitrarily assigned to one genus or the other. The diagnosis in any case turns upon the presence or absence of a surface net, formed, in Stemonitis, by the anastomosing of the ultimate divisions of the capillitial branches. In Comatricha the anastomosing is general, from the columella out, and is not specialized at the surface.

Recent attempts to reunite the genera here compared seem to result in no apparent advantage. The genera come very near together, but their separation along the line suggested by Rostafinski remains convenient."

Comatricha nigra is one of the most common species1. A partial sequence of the Comatricha nigra voucher AMFD155 small subunit ribosomal RNA gene from GenBank® can be found here DQ903683 2783 bp DNA linear INV 30-OCT-2008 10.

Further pictures and info for the genus Comatricha :

Site 1 8
Site 2 12
Site 3 13


The genus Comatricha is widely found1. For example, Comatricha suksdorfii is found in Washington D.C., U.S.A 6. In addition, Comatricha pulchelloides is found in Harderbos, Flevoland province, Netherlands 6, also collected near Kassel, Germany 6 2. Furthermore, Comatricha longa is found in the torrid zone 7 1. Finally, here is a link to The Eumycetozoan Project Map of Distribution for Comatricha 8 which shows the extent of Comatricha documentation around the world.


The genus Comatricha is found on decaying wood in most temperate weather conditions and tree bark in moist weather conditions3.

Look Alikes:

The genus Comatricha looks like the genus Stemonitis. For example, in the tropics, a common species Comatricha longa has considerable superficial resemblance to Stemonitis splendens1. Please refer to Diagnostic Description section for more info on this topic.


This is the abstract from Fiore-Donno, Meyer, Baldauf, Pawlowski (2008). This paper discusses how Comatricha has been used by scientists to establish evolutionary relationships through the use of molecular phylogenetics. Evolutionary relationships of Comatricha developed by morphology have been irresolute due to subjective interpretation of foggy characteristics. Molecular phylogenetics is a growing field4:

“The Myxomycetes are a major component of soil amoebae, displaying a complex life cycle that terminates in the formation of often macroscopic fruiting bodies. The classification of Myxomycetes is controversial and strongly depends on the weight given by different authors to morphological and developmental characters. We used a molecular approach to establish the phylogenetic relationships in the dark-spored orders Stemonitales and Physarales. Twenty-five small subunit ribosomal RNA gene sequences were obtained, with focus on two Stemonitales genera, Lamproderma and Comatricha. Unexpectedly, our results show that Stemonitales are paraphyletic with Physarales arising from within a Lamproderma clade. The genus Lamproderma itself is polyphyletic and can be divided into two distinct clades. Additionally, we found that Comatricha nigri capillitia comprises two cryptic species, both related to Enerthenema. Our study allows the reappraisal of morphological and developmental characters in the light of molecular data and sets foundations for a new classification of Myxomycetes.”

Another recent research paper regarding Comatricha:
Cutting edge research regarding the genus Comatricha 14


1 Martin, G. W., Alexopoulos, C. J., & Farr, M. L. (1983). The Genera of Myxomycetes. Iowa City: University of Iowa Press. p. 84-85.

2 Nannenga-Bremekamp, N. E. (1991). A guide to Temperate Myxomycetes. Bristol: Biopress. p. 345-360.

3 Stephenson, S. L., & Stempen, H. (1994). Myxomycetes: A handbook of slime molds. Portland, Or: Timber Press. p. 97-99.

4 Fiore-Donno AM, Meyer M, Baldauf SL, & Pawlowski J. (2008). Evolution of dark-spored Myxomycetes (slime-molds): molecules versus morphology. Molecular Phylogenetics and Evolution. 46 (3), p. 878-89.

5 Mycobank administration. (January 1, 2000). MycoBank, the fungal website. In Genus Comatricha Preuss 1851 MB12049 . Retrieved December 5, 2008, from

6 Google Maps. Retrieved December 5, 2008, from

7 HorsePunchKid. (February 13, 2007). Image:World map torrid.svg. In Wikipedia, the free encyclopedia. Retrieved December 5, 2008, from bq.

8 Liu, Chin-Hui . (2006). In The Eumycetozoan Project. Retrieved December 5, 2008, from

9 Simmons, Kent. (2005). 16PROTIS. In BIOLOGY 05.1116/3. Retrieved December 5, 2008, from

10 In National Center for Biotechnology Information. Retrieved December 5, 2008, from

11 Macbride, T. H. (1922). The North American slime-moulds; A descriptive list of all species of Myxomycetes hitherto reported from the continent of North America, with notes on some extralimital species. New York: Macmillan. p. 123-124.

12 (November 4, 2008). Comatricha nigra. In ZipcodeZoo. Retrieved December 5, 2008, from

13 Genus: Comatricha. In Global Biodiversity Information Facility. Retrieved December 5, 2008, from

14 Mandeel QA, & Blackwell M. (2008). Rare or rarely collected? Comatricha mirabilis from the desert of Bahrain. Mycologia. 100 (5).

Description author: Jason Liu (Request Authorship Credit)
Description editors: Administrator, Thomas Laxton

Created: 2008-12-02 22:35:14 PST (-0800) by Jason Liu (jgliu)
Last modified: 2015-04-12 18:11:17 PDT (-0700) by Thomas Laxton (Tao)
Viewed: 3735 times, last viewed: 2018-06-26 19:24:50 PDT (-0700)