The North American Slime-Moulds Part 46

=Key to the Genera of the Lamprodermaceae=

_A._ Columella percurrent; capillitium from a disk at the apex 1. ENERTHENEMA

_B._ Columella scarce reaching the centre of the sporangium.

_a._ Capillitium not forming a net 2. CLASTODERMA

_b._ Capillitium forming an intricate net 3. LAMPRODERMA

_c._ Minute, capillitium rudimentary 4. ECHINOSTELIUM

=1. Enerthenema= _Bowman_

1828. _Enerthenema_ Bowman, _Trans. Linn. Soc._, XVI., p. 152.

Sporangia stipitate, the stipe extended as a columella, which entirely traverses the sporangium and forms at the apex an expanded disk; from this depends the capillitium.

=Key to the Species of Enerthenema=

_A._ Spores free 1. _E. papillatum_

_B._ Spores in cl.u.s.ters 2. _E. berkeleyanum_

1. ENERTHENEMA PAPILLATUM (_Pers._) _Rost._

PLATE V., Fig. 3.

1801. _Stemonitis papillata_ Pers., _Syn._, p. 188.

1828. _Enerthenema elegans_ Bowm., _Trans. Linn. Soc._, XVI., p. 152.

1862. _Comatricha obtusata_ Preuss, Sturm, _Deutschl. Flora_, Pl. LXX.

1876. _Enerthenema papillatum_ (Pers.) Rost., _Mon. App._, p. 28.

Sporangia scattered or crowded, stipitate, spheroidal, naked, black fuscous, above, s.h.i.+ning, adorned with a minute, black papilla; stipe black, opaque, conical or attenuate upward, about equal to the peridium; columella at the apex expanded into a s.h.i.+ning disk; capillitium springing from the lower side of the disk or from its edge, made up of scarcely forked threads which are free below; spores violaceous or fuscous black, minutely warted, 10-12 .

Rare. Wisconsin, Ohio, South Carolina, Illinois, Pennsylvania, Iowa, Colorado.

This is one of the few species so well marked that Persoon's description, _l. c._, is definitive: "Stylidio toto penetrante.

Capillitium exacte globosum, sub-compactum, in eius apice stylidium papillae in modum prominet." For this reason Bowman's specific name _elegans_ is discarded.

2. ENERTHENEMA BERKELEYANUM _Rost._

1876. _Enerthenema berkeleyanum_ Rost., _Mon. App._, p. 29.

1913. _Enerthenema syncarpon_ Sturgis, _Myxo. Col._, II., p. 448.

This species corresponds to the preceding in all respects except in the fact that the spores are cl.u.s.tered in groups of four to twelve and are a little larger, 11-13 , strongly spinulose on the exposed surface.

Dr. Sturgis reports this from Colorado, _l. c._, but discards Rostafinski's specific name on the ground that the type has disappeared; only the spores of some fungus hyphae remain in the place and these may have been mistaken by Berkeley. This seems hardly possible since such supposition would not account for the generic reference either by Berkeley (and Broome) or by Rostafinski. The description in the _Monograph_ is minute as that of one who had the form under his lenses.

Rostafinski _saw_ Berkeley's specimens.

For a similar case, see under _Prototrichia metallica, Mycetozoa 2nd ed._, p. 261.

South Carolina, type; Colorado.

=2. Clastoderma= _Blytt_

1880. _Clastoderma_ Blytt, _Bot. Zeit._, x.x.xVIII., p. 343.

Sporangium globose, distinct, stipitate; the columella short or obsolete; the capillitium of few spa.r.s.ely branched threads, which bear at their tops the persistent fragments of the peridium, but are not otherwise united.

Distinguished from _Lamproderma_ by the peculiar manner in which the peridium is ruptured, and by the simplicity of the scanty capillitium.

So far there appears to be but a single species.

1. CLASTODERMA DEBARYANUM _Blytt._

PLATE XIII., Fig. 6, and PLATE XVI., Fig. 13.

1880. _Clastoderma debaryanum_ Blytt, _Bot. Zeit._, x.x.xVIII., p. 343.

1886. _Orthotrichia microcephala_ Wing., _Jour. Myc._, II., p. 126.

Sporangia scattered or gregarious, very minute, 1-12 to mm. in diameter, the peridium fugacious, except the minute patches that adhere to the capillitial branchlets, and the slight annulus at the base of the columella; stipe long, unequal, dark below, above paler; columella almost none, giving early rise to the comparatively few slender threads which by their repeated forking make up the capillitium; spores globose, even, violaceous, 8-9 .

Reported in the United States so far from Maine, Pennsylvania, Ohio, and Illinois.

The sporangia are very small, but beautiful, delicate little structures, found on the bark of living red oak in this country; in Norway it seems to have been seen first on a dead polyporus. Its minuteness doubtless causes it to be generally overlooked, _N. A. F._, 2498.

=3. Lamproderma= _Rostafinski_

1873. _Lamproderma_ Rostafinski, _Versuch_, p. 7.

Sporangia stipitate, globose, or ellipsoid; columella cylindric or inflated or clavate at the apex, scarcely attaining half the height of the peridium; peridium s.h.i.+ning with metallic tints, deciduous, except where, at the base of the columella, it forms a ring around the stipe; capillitium rising in tufts or by simple branches from the columella, the threads regularly forked, generally united into a net.

The lamprodermas are distinguished from the comatrichas, to which they are most nearly allied, by the arrangement of the capillitium, its development from the apex only of the columella, the continuation of the stipe within the peridium. In other words, the peridium leaves the stipe some distance below the point where the lowest capillitial branches take origin. In mature specimens the peridium has often entirely disappeared, its only trace, a collar, more or less distinct, around the stipe, marking the beginning of the columella. Nevertheless the peridium is far more persistent than in any comatricha, and shows in yet greater brilliancy the wondrous metallic tints and iridescence of _Comatricha_ and _Diachaea_. Older authors, so far as can be seen, distributed the species between _Physarum_ and _Stemonitis_.

=Key to the Species of Lamproderma=

_A._ Peridium metallic blue.

_a._ Stipe short, stout.

1. Capillitium tips colorless 5. _L. violaceum_