17. BADHAMIA SUBAQUILA _Macbr._
1899. _Badhamia subaquila_ Macbr., _N. A. S._, p. 64.
Sporangia closely gregarious or crowded, globose or sub-globose, sessile, brown, the peridium a thin but persistent brown membrane, rupturing above irregularly and remaining as a cup after spore dispersal; hypothallus none; capillitium strongly developed, thoroughly calcareous, the meshes large, the nodular thickenings broad, white; spores globose, in ma.s.s black, by transmitted light brown, very rough-warted, large, 15-18 .
The variety is founded on material sent from Maine by the late Mr. F. L.
Harvey. Professor Harvey, upon the authority of Mr. Morgan of Ohio, quotes the species, _Bull. Tor. Bot. Club_, 24, 67, as _B. verna_ (Somm.) Rost. But the specimens certainly do not conform to description of _B. verna_. Here the wall corresponds with what is seen in _B.
rubiginosa_; but the spores are much larger, and the capillitial structure very different.
Miss Lister regards this a form of No. 16. So far, the original gathering represents the species; but the woods of Maine are certain one day to send added information.
Rare. On mossy logs, Maine.
=3. Physarum= (_Persoon_) _Rost._
1794.[19] _Physarum_ Pers., _Rom. Neu. Mag. f. d. Bot._, I., p. 88, in part.
1795. _Physarum_ Pers., _Ust. Ann. Bot._, XV., p. 5, in part.
1801. _Physarum_ Pers., _Syn. Fung._, p. 168, in part.
1829. _Physarum_ (Pers.) Fries, _Syst. Myc._, II., p. 127, in part.
1875. _Physarum_ (Pers.) Rost., _Mon._, p. 93.
Sporangia plasmodiocarpous, aethalioid or distinct; the peridium usually simple, sometimes double, irregularly dehiscent, more or less definitely calcareous; capillitium a uniform irregular net, dilated and calcareous at the nodes, adherent on all sides to the peridial wall.
This large and cosmopolitan genus is readily recognized by the characters quoted. It may be added that the capillitial threads are always exceedingly delicate, probably tubular, but never filled with lime throughout; the peridium may be almost nude or encrusted with lime, which, where present, is always amorphous, never crystalline; the sporangia when distinct may be either sessile or stipitate, and the stipe in the latter case is often hollow and charged with lime. In capillitium intermediate between _Leocarpus_ and _Badhamia_, since in the first the capillitium is unequally calcareous, diverse, while in _Badhamia_ the capillitium is intricate and calcareous throughout.
As first set up by its founder, the genus included diverse forms, only one or two of which would be included in the genus as now limited.[20]
Persoon, however, was left to develop the matter to suit himself, and in successive works gave, under this generic name, more and more prominence to forms now so referred. Fries, _Syst. Myc._, III., pp. 127 _et seq._, still better establishes the genus, though still including forms that, judging from the description, seem to belong elsewhere. Twenty years later Fries revising somewhat his earlier work thought to improve the chances of future students by reducing the number of physarums. This he would do by setting out certain evidently inter-related forms to make a new genus, _Tilmadoche_.
He named two or three species only, leaving his sucessors to add others as occasion offered.[21]
Rostafinski approved the good intention of Fries, but in the _Monograph_, he entirely re-cast the genus as const.i.tuted by Fries; actually called the species "first cited" a typical physarum! Would not have it in the new genus at all, first or last; but instead took the second species of Fries as the type and added several forms, some from the Friesian list, to make up a respectable group.
Until quite recently writers on the subject have generally approved the course adopted by the Polish author. The arrangement showed features of convenience, even if artificial to a degree. Perhaps we gain advantage in all directions if we treat the original genus _Physarum_ as a whole, but in the key take advantage of Fries" suggestion. We may write--
=Key to the Species of Physarum=
1. Capillitium irregularly reticulate throughout; calcic nodes various _Physarum_
2. Capillitium more regular, especially below, furcate; nodes fusoid _Tilmadoche_
SECTION I. PHYSARUM
I. Fructification not stipitate, more or less plasmodiocarpous.
1. Peridium simple.
_a._ Calcareous deposits yellow 1. _P. serpula_
_b._ Calcareous deposits reddish or orange 2. _P. lateritium_
_c._ Calcareous deposits white, peridium rugulose 3. _P. vernum_
2. Peridium double.
_a._ Fructification flatly compressed 4. _P. sinuosum_
_b._ Fructification less compressed, rounded.
i. Outer peridium white 5. _P. bitectum_
ii. Outer peridium brown or brown-tinged 6. _P. bogoriense_
iii. Outer peridium yellow; capillitium yellow 7. _P. alpinum_
II. Fructification of sporangia more or less distinct.
A. Sporangia sessile, globose, ovoid, reniform, etc.
1. Peridium double.
_a._ Sporangia white, peridium testaceous. 8. _P. diderma_
_b._ Sporangia tinged with yellow.
i. Sporangia as if interwoven, compressed 9. _P. contextum_
ii. Sporangia more nearly free, distinct.
o Spores pale, inner peridium brittle 10. _P. conglomeratum_
oo Spores spinulose, dark violet 11. _P. mortoni_
_c._ Sporangia brown, dehiscence revolute 12. _P. brunneolum_
2. Peridium simple, calcareous, flaky.
_a._ Sporangia grey, plasmodiocarpous; spores dusky, 10-12 forms of 3
_b._ Sporangia grey, more or less dense; spores violet, 6-7 13. _P. cinereum_
_c._ Calcareous deposits yellow or greenish, spores 7-9 14. _P. virescens_
_d._ Sporangia rusty or reddish brown, more or less dense 15. _P. rubiginosum_