4. Diachæa Fries
- 1825. Diachaea Fries, Syst. Orb. Veg., I., p. 143.[38]
Sporangia distinct, globose or cylindric, the peridium thin, iridescent, stipitate; the stipe and columella surcharged with lime, white or yellowish, rigid, thick, tapering upward; capillitium of delicate threads free from lime, radiating from various points on the columella, branching and anastomosing as in Comatricha to form a more or less intricate network, the ultimate branchlets supporting the peridial wall.
Rostafinski placed this genus near the Didymieae on account of the calcareous columella and the non-calcareous capillitium. On the other hand the structure of the capillitium and the iridescent simple peridium ally Diachaea to Lamproderma and the Stemoniteae; the only distinction being the calcareous stem. It is simply an intermediate genus to be placed here more conveniently than anywhere else in what is of necessity a linear arrangement.
Key to the Species of Diachæa
| A. Stipe and columella white. | ||||
| a. Sporangium cylindric | 1. D. leucopodia | |||
| b. Sporangium globose. | ||||
| i. Evidently stalked | 2. D. splendens | |||
| ii. Stalk very short, 5 mm., conic. | ||||
| O Spores warted | 3. D. bulbillosa | |||
| OO Spores faintly netted | 4. D. subsessilis | |||
| B. Stipe yellowish or orange | 5. D. thomasii | |||
1. Diachaea leucopodia (Bull.) Rost.
- 1791. Trichia leucopodia Bull., Champ. de la France, Pl. 502, Fig. 2.
- 1825. Diachaea elegans Fries, Syst. Orb. Veg., I., p. 143.
- 1875. Diachaea leucopoda (Bull.) Rost., Mon., p. 190.
Sporangia rather closely gregarious, metallic blue or purple iridescent, cylindric or ellipsoidal, obtuse, sub-umbilicate below, stipitate; stipe short, much less than one-half the total height, snow-white, tapering upward; hypothallus white, venulose, occurring from stipe to stipe to form an open network over the substratum; columella thick, cylindric, tapering, blunt, terminating below the apex, white; capillitium springing from every part of the columella, of slender threads, brown, flexuous, branching and anastomosing to form an intricate net; spores in mass nearly black, by transmitted light dull violaceous, minutely roughened, 7–9 µ.