Cavenderia minima Cavender, Vadell, J.C. Landolt, S.L. Stephenson, S. Baldauf & N. Cavender, 2018

Cavender, James C., Vadell, Eduardo, Landolt, John C., Stephenson, Steven L., Baldauf, Sandra L., Roux, Jolanda, Cavender, Nicole & Winsett, Katherine E., 2018, New dictyostelid cellular slime molds from South Africa, Phytotaxa 383 (3), pp. 233-251 : 237-247

Cavenderia minima Cavender, Vadell, J.C. Landolt, S.L. Stephenson, S. Baldauf & N. Cavender (Eden 1) Figs. 3A–I ,

4A–D

MycoBank MB827789

Type: — SOUTH AFRICA, Birds of Eden Park near Tsitsikamma National Park in the Western Cape, 33°57’53” S, 23° 28’60” E, elev. ca 220 m, October 2006, leg. J. C. Cavender

Eden 1 (Holotype), deposited in the American Type Culture Collection as MYA–4149. GenBank accession number MH 762954.

Diagnosis: —Sorocarps solitary to clustered, hyaline-white, very small, prone, decumbent, erect, generally unbranched, wavy, sinuous and curved, stoloniferous ( Figs. 3C , 4B ), variable in height, 0.2–2 mm (mostly 0.4–1.5 mm.), when cultivated on E. coli at 20–24 °C. Sorophore curved, mostly consisting of one tier of cells, irregular, almost nontapered (7 μm at the base to 2–5 μm at the tip), with a dense hyaline sheath. Lower sorophore sometimes prostrate and multicellular. Tip capitate flexuous, 3–5 μm diam. (subtips and upper segment) ( Fig. 3F ). Base commonly clavate to roundish, 1–6 celled (7–20 μm), within a disk-like mass of conical mucilage (20–40 μm). Basal terminal cell resting on a dense cushion of slime ( Fig. 3E ). Sori globose to globoid, hyaline, 10–45 μm diam. (Figs, 3D, 4B). Spores small, elliptical to oval, with conspicuous consolidated polar/subpolar granules of different sizes (range: 7.4–6.3 × 2–3.4 μm [ave. 5.51 × 2.70 μm]), two times longer than broad, with a heterogeneous content, often with one much larger cluster of granules at one pole, with halos, tiny granules dispersed ( Figs. 3H , 4D ). Aggregations small, 30–50 μm diam., irregular amorphous, hyaline at first, with few short ample streams with open blunt ends, becoming irregular to regular mounds ( Figs. 3A , 4A, 4C ). Some masses of pseudoplasmodia are left behind. Early sorogens small, broad, amorphous. Late sorogens enlarged, ample, 300–400 μm long, with a regular blunt tip, may collapse and begin migrating freely or enlarge as a globoid mass ( Figs. 3B , 4C ).

Etymology:—The name minima (small) refers to the small amount of biomass obtained from each inoculum and the size of the sorocarps.

Habitat:—This species was isolated from soils of a subtropical forest. It is currently known only from the type locality.

Notes:—This species is phylogenetically close to Cavenderia amphispora (Cavender, Vadell, J.C. Landolt & S.L. Stephenson) S. Baldauf, S. Sheikh & Thulin. Solitary sorocarps rise up from isolated small aggregations, separate from each other, small and unbranched in younger cultures. Clusters commonly grouped (400 μm), each one 50–100 μm with scarce sorocarps (2–7), becoming coremiform in the lower sorophore section and largely branched, when cultures are old and dense. Flexuous tip terminating in a cushion of slime, sometimes divided into 2–3 short slimy granular extensions, shortly to long piliform ( Fig. 3F ). Terminal cell with refringent granules (1 μm). Sori may collapse or be well separated from each other in younger cultures, then with a tendency to become tangled or soon drying out, then cream colored. Sori that fall and do not collapse (which do not germinate immediately) become covered by a film of slime (80 μm diam.), their spores slowly germinate into roundish myxamoebae. Large encysted myxamoebae occur in groups surrounding small bases (7 μm). Late sorogens may migrate shortly and become 1–3 times stoloniferous in habit. Larger aggregations produce clustered sorogens. Groups of aggregations are close to one another, smaller ones are strictly mounds (30–50 μm), producing a single central sorogen, late aggregations are mounded, elevated, shortly streamed, irregular, much larger with lobed short ample granulose streams, the flat streams terminating unfinished, open to incoming myxamoebae or with a lobular terminus ( Figs. 3A , 4A ), most spores show one larger extreme, in which a more conspicuous group of clustered polar granules contrast with the opposite pole, they split longitudinally, straight or sigmoidal from one pole to the other ( Fig. 3I ), smaller spores are vacuolated. Sorocarps may develop more than one large (700–1000 μm) and small branches in old cultures. Late sorogens may develop decumbent fruiting bodies and begin 1–3 generations until the rise of erect fruiting bodies. Some of the fallen sori aggregate with a streamed radiate pattern (70–150 μm diam.). Many spores do not germinate and, as is the case for the others, remain free of mucilage. This species adapts poorly to a new environment but once established endures for a long time in a culture and tolerates well a wide range of temperatures.

Hagiwaraea tenebrica Cavender, Vadell, J.C. Landolt, S.L. Stephenson, S. Baldauf & N. Cavender (Ong 2) Figs. 5A–I , 6A–D MycoBank MB827790 Type: — REPUBLIC OF SOUTH AFRICA, Ongoye Forest Reserve in the region the country referred to a Zululand, 28°49’56” S, 31°

44’12” E, elev. ca 300 m, October 2006, leg. J. C. Cavender Ong 2 (Holotype), deposited in the American Type Culture Collection as MYA–4151. GenBank accession number MH762956.

Diagnosis: —Sorocarps solitary to clustered, erect, prone to decumbent, generally unbranched, 0.5–4.5 mm but commonly 2–3 mm tall, pigmented, when cultivated on E. coli at 15–24 C. Sorophores curved, generally consisting of one tier of cells except for the basal section, bluish-violet, tapered from the base (20–90 μm diam.) to the lower sorocarp (7–10 μm diam.) and becoming thin at the middle-upper portion of the sorophore (5–10 μm). Tip capitate and consisting of flexuous small cells, covered with dense mucilage and flexuous cells (tips and subtips), with refringent particles that sometimes keep spores attached (7–25 μm diam.) ( Fig. 5F ). Base commonly developing 1 to 5 well-defined cellular crampons, each consisting of one tier of cells or as 3–4 prominent separated cells (23–30 μm diam.) ( Figs. 5E , 6C ). Sori globose to globoid, purple-brown, 20–90 (–180 μm) μm in diam., soon drying out ( Fig. 6B ). Spores elliptical, irregular, size range of 4–9.5 × 2–4 μm but mostly 6–7.5 × 3–4 μm (ave. 6.3 × 3.3 μm), generally 2–2.3 times longer than broad, with vacuoles and a heterogeneous content, with consolidated large and small granules mostly at the poles but sometimes also loosely dispersed ( Figs. 5I , 6D ). Spore cases open at the equator, irregular, germinating immediately ( Fig. 5H ). Aggregations mound-like or irregularly streamed (150–200 μm), reuniting together to form a mass from which each cupuliform early sorogen arises from its center. Later, the massive aggregations become amorphous, with short remaining streams. Single small aggregations may develop flat irregular discontinuous streams that end anastomosed and lobed ( Figs. 5A , 6A ). Mature bases may be surrounded by a halo consisting of a mass of remaining pseudoplasmodia and mucilage, mostly discontinuous, as a remnant of the aggregation, rarely forming a complete circle ( Figs. 5C, 5D ). Microcysts present ( Fig. 5G ).

Etymology: —The name tenebrica refers to the dark color of the sorocarps.

Habitat: —This species was isolated by J. C. Cavender from soils of a remnant subtropical forest (bushvelt) in a ravine surrounded by grassland. It is currently known only from the type locality.

Notes: —This species differs from H. coeruleostipes (Raper & Fennell) S. Baldauf, S. Sheikh & Thuin and H. vinaceofusca (Raper & Fennell) S. Baldauf, S. Sheikh & Thuin (formerly Dictyostelium vinaceofuscum ) mostly in the size of the sorocarps, the more irregular spores with consolidated polar and dispersed granules, aggregations with shorter expanded streams, the color of the sori, and at least in contrast to H. vinaceofusca , and the larger well-defined crampon bases. The species develops rapidly within 24 hr, and when tightly clustered, 2–12 late sorogens rise up in a coremiform habit and then the upper segments separate from each other. Early sorogens are central, pear-shaped until achieving a thin, elongated finger-like shape (50–100 μm long). Late coremiform sorogens may be prone, elongated, with the mass of some differentiable oblong cells at their tip (the cells 200–700 μm long), then they separate from each other and may creep on the agar. Sori pigmentation may fade while the stalk retains its color. Sorophores are covered with a dense sheath, with pigmented refringent particles. Slime also is dense and with amorphous cells and pigmented large particles near or at the base. Thin upper sorophores may be tortuous (consisting of one tier of cells), the terminal segment is dark and colorful. In larger and older sorocarps, the base develops 4–5 crampons consisting of 2 to more cells of different shapes, ending as a cone-shaped structure. These old sorophores have 5–6 lines of cells at the middle point (15–40 μm diam.). Crampon bases rest on a cushion of pigmented slime with large refringent particles. Some closely adjacent myxamoebae join and round up, initiating an aggregation. Pigmentation of the sorus is variable and fades to citrine yellow, olive to pale brown, affected by the culture conditions. Color of the whole base differs from that of the stalk and sorus in fully developed sorocarps. Pigmented crampon bases become fuscous in age and the base may produce a cavity in the agar ( Fig. 5E , center). This species is well-adapted to dry culture conditions, as well as to a range of temperatures (15–28°C), may persist in cultivation for several weeks. Myxamoebae active at 34°C.

Heterostelium irregularibrachiatum Cavender, Vadell, J.C. Landolt, S.L. Stephenson, S. Baldauf & N. Cavender (Krug 6–5B) Figs. 7A–H , 8A–D MycoBank MB827791 Type: — REPUBLIC OF SOUTH AFRICA, Kruger National Park, on S1 tar road between Phabeni Gate and Skukuza Camp, 25°05’34” S,

31° 14’46” E, elev. ca 530 m, August 2006, leg. J. C. Cavender 6–5B (Holotype), deposited in the American Type Culture Collection as MYA–4152. GenBank accession number MH762955.

Diagnosis: —Sorocarps solitary to tightly clustered, curved, mostly decumbent, semi-erect, prone, stoloniferous, asymmetrical, 3–5 mm tall, commonly with 4–8 (–12) whorls in groups, coremiform when clustered ( Figs. 7C, 7D , 8C ), when cultivated with E. coli on non-nutrient agar at 15–24 ° C. Sorophores delicate, sinuous, sometimes 1–2 times broken and knotted ( Figs. 7D , 8C ), 5–10 to 12–15 μm in diam. at the middle, consisting of 1–2 tiers of cells. Middle to lower portion of coremiform sorophores occurring in groups of 2–6 or more within a cluster, then the middle-upper sorophores separate ( Fig. 7C ). Whorl nodes 4–8, internodes 200–300 μm, internode gaps variable, mostly 300–700 μm, whorl formation begins at 600–1000 μm from the base. Branches of whorls curved, varying in length (100-350 μm, mostly 150-200 μm) and number (2–3, few 4–5), each consisting of one tier of cells, with clavate single bases, with blunt terminal basal cells (Figs, 7F, 8C). Larger irregular branches out of whorls are common (0.2–1 mm), sometimes straight, each consisting of 1–3 tiers of cells. Lower sorphores attached by the side (in tight clusters) and their bases resting on a dark cushion of slime, within yellowish mucilage ( Fig. 7E ). Sorocarps decumbent to prostrate, diverging from each other, endings flexuous (in loose clusters). Terminal segment elongated, 0.7–1 mm. Terminal sori globose, hyaline-white, 70–150 μm in diam., lateral sori hyaline, 40–90 μm in diam. Spores elliptical-oblong, variable in size, broad, 5–9 × 3–5.5 μm, commonly 5.5–7 × 3–4 μm to 6–7 × 4 μm (ave.: 6.8 × 3.8 μm), 1.5–1.8 times longer than broad, with unconsolidated polar/subpolar small granules, also dispersed with tiny vacuoles, spores germinate immediately ( Figs. 7H , 8D ). Aggregations radiate, of the “ violaceum ” type, small (0.3 mm) and large (0.5–1 mm), streams gently curved, elongated, converging acutely to a condensed center, streams with no large variation in section, disrupted and open at the end ( Figs. 7A , 8A ). Large pseudoplasmodia with many (20–30) crowded cupuliform sorogens. Late sorogens elongated, free or coremiform in a cluster ( Figs. 7B , 8B ). Large numbers of microcysts surrounding aggregations (under dim illumination and at lower temperatures) ( Figs. 7A, 7C, 7G , 8A ).

Etymology:—The name irregularibrachiatum refers to the irregularity of the branches on the sorocarp.

Habitat:—This species was Isolated by J.C. Cavender from soils of a subtropical woodland (bushveld) in Kruger National Park. It is currently known only from the type locality.

Notes:—Large irregular branches out of whorls, the coremiform clustered habit, knotted, broken and curved sorophores, spore dimensions and content, bases and whorled branches, and commonly the small number of whorls, separate this species from H. asymetricum (Vadell & Cavender) S. Baldauf, S. Sheikh & Thuin and H. colligatum (Vadell & Cavender) S. Baldauf, S. Sheikh & Thuin as well as three other similar isolates— H. pseudocolligatum [Cavender, Vadell, J.C. Landolt & S.L. Stephenson] S. Baldauf, S. Sheikh & Thulin, H. perasymmetricum [Cavender, Vadell, J.C. Landolt & S.L. Stephenson] S. Baldauf, S. Sheikh & Thulin and H. multimicrocystatum [Cavender, Vadell, J.C. Landolt & S.L. Stephenson] S. Baldauf, S. Sheikh & Thulin) from Madagascar. Semi-erect sorocarps in a cluster are less frequent than decumbent to prostrate ones. Decumbent sorocarps form ample irregular arches coming from clusters, these sorocarps may become prostrate and keep creeping on the agar until the formation of a smaller sorocarp, away from the cluster, or continue in a stoloniferous habit ( Figs. 7C, 7D ). Older sorocarps of different diameters within a cluster are covered by a thin hyaline sheath. One to three tiers of cell bases may have lateral supportive cells (2–3) situated at right angles with respect the base (in solitary old sorocarps), sometimes with minute basal branches of three cells that form an angle directed toward the base (with one large cell perpendicular to the axis and two cells that follow at an angle of 90 degrees downwards), forming “short stolons” Fig. 7E , below left). Old solitary sorophores may reach 35–40 μm in diam., 6–7 mm in length when decumbent, up to 1 cm when prostrate, phototropic. Whorled branches are knotted and occur at an angle at middle length, with a small protrusion opposite to the angle (ca. 90–120 degrees), as observed in single larger sorocarps ( Fig. 7F ). Late sorogens and sorocarps in a tight cluster are coremiform, distributed in fasciculi, 2–3 groups of 2–4 and 6–12 or more tightly united ( Figs. 7C, 7E ).

Raperostelium cymosum Cavender, Vadell, J.C. Landolt, S.L. Stephenson, S. Baldauf & N. Cavender (Krug 15A) Figs. 9A–I , 10A–D MycoBank MB827792 Type: — REPUBLIC OF SOUTH AFRICA, Kruger National Park, on S1 tar road between Phabeni Gate and Skukuza Camp, 25°05’34” S,

31° 14’46” E, elev. ca. 530 m, August 2006, leg. J. C. Landolt 15A (Holotype), deposited in the American Type Culture Collection as MYA–4147. GenBank accession number MH762958.

Diagnosis: —Sorocarps erect, prone, generally tightly clustered (2–12), coremiform in the basal portion, branched, solitary, variable in height, 0.3–3.5 mm but mostly 0.5–3 mm., branches and main stalks are of different sizes, when cultivated on E. coli at 20–24 °C. Sorophores delicate, irregular, tortuous, curved, commonly consisting of one tier of cells except for some bases, tapering from 5–20 μm in the basal portion to 1–5 μm at the tip, sorophore diameter variable. Long curved sinuous branches formed from tightly adjacent rising pseudoplasmodia, these may rebranch close to or from the base ( Figs. 9C, 9E , 10C ). Tips variable, short and elongated piliform (1 μm, 35–55 μm long), 1–2 short and elongated (2–5 μm diam.), pyriform capitate, amorphous flexuous, curved ( Fig. 9G ). Base clavate to roundish (10– 25 μm diam.), with protruding terminal cells ( Fig. 9F ). Branches coming from the basal section may reach the height of primary sorocarps, curved, sigmoid, commonly rising up at acute to ample angles with respect the main axis. Sori globose, hyaline-white, 40–170 μm in diam., variable in a single cluster ( Figs. 9E , 10C ). Spores elliptical, reniform, not regular, range 5–12 × 2.5–5 μm (ave.: 7.75.1 × 3.80 μm), (other measurement: ave.: 8 × 3.7 μm), mostly 7–8 × 3–4 μm, with prominent consolidated polar to subpolar granules ( Fig. 9I , 10D ). Early sorogens minute (10–20 μm ( Figs. 9B , 10B ). Late sorogens enlarged (600–800 μm) ( Figs. 9B , 10C ). Aggregations are small, 50–150 μm in diam., with an amorphous diffuse lobulated margin as short streams, that condense into mounds with incoming myxamoebae ( Figs. 9A , 10A ). Close aggregations of this kind form a bridge of myxamoebae and form a larger one, flattened with diffuse lobulated margins that resume into extremely thin anastomosed streams. Myxamoebae large, 25–27 × 9–15 μm. Microcysts present and dispersed among surrounding aggregations ( Figs. 9H , 10A ).

Etymology:— The name cymosum refers to the “cyme-like” arrangement of branches on the sorocarps.

Habitat: —This species was isolated by Landolt from soils of a sub-tropical woodland (bushveld) in Kruger National Park. It is currently known only from the type locality.

Notes:—This species is morphologically close to D. monochasioides (Hagiw.) S. Baldauf, S. Sheikh & Thuin but differs in the height, spore shape and size, and granules. It is very much irregular in terms of the tip and base morphology. A cluster is formed by 2–3 or more primary sorocarps and the incoming masses of sorogens that form new sorocarps as ascending branches.A mature cluster may contain 12 sorocarps. Profuse mucilage and a sheath cover the lower part of the Sorophore ( Fig. 9E, 9F ). Rebranching begins its formation from late incoming pseudoplasmodial masses. Terminal sections are generally curved and when piliform may lack a sorus and be attached to other cells and spores by lines of sheath material ( Fig. 9G ). The clavate base rests on a minute cushion of dark slime or on a cellular formation, sometimes with 1–3 larger elongated crampon-like terminal cells and sometimes with a flexuous formation (10–25 μm in diam.) ( Fig. 9F ). One tier of cell sorophores may not develop protruding terminal cells at the base and are clavate or plane (10 μm). They are curved, in contact with each other by their terminal basal cells, when clustered. Early sorogens are minute (10–20 μm), with thin anastomosed ample streams (150–200 μm). Late sorogens are lageniform, 600–800 μm. The base of the sorogen has a striated sheath. Isolated late myxamoebae continue migrating toward sorogens. Anastomosed remaining thin streams are also in contact with the base ( Fig. 9B ). Solitary early sorogens are much larger, ultimately becoming lageniform with a pyriform terminus, regular, prone. Late solitary sorogen are prone, with the mass of developing spores within a pyriform regular upper formation or, in other cases, enlarged, fusiform and with constrictions and with a blunt end.

Raperostelium crispum Cavender, Vadell, J.C. Landolt, S.L. Stephenson, S. Baldauf & N. Cavender (Eden 2) Figs. 11A–I , 12A–D MycoBank MB827793 Type: — REPUBLIC OF SOUTH AFRICA, Birds of Eden Park near Tsitsikamma National Park in the Western Cape, 33°57’53” S,

23°28’60” E, elev. ca 220 m, leg. J. C. Cavender Eden 2 (Holotype), deposited in the American Type Culture Collection as MYA–

4150. GenBank accession number MH762957.

Diagnosis: —Sorocarps solitary to tightly clustered, crowded, curved to twisted and helicoidal, prone, decumbent to prostrate, unbranched to branched, sometimes coremiform, irregular ( Figs.11D, 11E , 12B ), 0.4 to 2.0 mm tall, commonly 0.6–1.5 mm, when cultivated on E. coli at 20–25°C. Sorophore irregular, not tapered to irregularly tapered (3–7 μm in diam.), sometimes tortuous, broken, generally consisting of one tier of cells, with segments of 2–3 cells.

Base clavate, single celled to massive, mostly curved, sometimes amorphous, 8–20 μm in diam., with abundant dense opaque mucilage and a striated cone-like sheath, surrounded by a distinguishable halo and/or fine late curly streams ( Figs. 11C, 11E, 11F ). Tip variable, capitate, piliform, flexuous, with one-two terminal cells drastically bent over, sometimes circinate (≤1–4 μm in diam.), with a sticky mass of slime that may attach a few spores ( Fig. 11G ). Sori globose to globoid, at first white but becoming cream, 40–80 (–100) μm. Spores oblong, short, broad, not regular, range 4–8 × 2.2–4.2 μm, ave. 5.5. × 3.2 μm (ave. of the most common 4.57 × 2.98 μm), with variable unconsolidated polar/subpolar granules, also with tiny dispersed granules, vacuoles and with a heterogeneous content ( Figs. 11I , 12D ). Aggregations are small (200–300 μm), irregularly streamed, streams are flat, irregular in section, broken, curly and interconnected, then disrupted to form separate discrete minute mounds 40–80 μm in diam. ( Figs. 11A , 12A, 12C ). One central early sorogen arises from each mound. Larger aggregations (350–400 μm diam.) form many clustered small sorogens that soon emerge ( Figs. 11B , 12C ). Myxamoebae 4–10 × 15–18 μm, with one to two large vacuoles ( Fig. 11H ), interact rapidly with other myxamoebae.

Etymology:—The name crispum , refers to the curly appearance of the streamed aggregations and their commonly occurring remnants at the bases of the sorophores.

Habitat: —This species was isolated by J. C. Cavender from soils of a subtropical forest in Birds of Eden Park near Tsitsikamma National Park on the Eastern Cape. It is currently known only from the type locality.

Notes: —This species differs from R. minutum (Raper) S. Baldauf, S. Sheikh & Thuin and R. ohiense (Cavender & Vadell) S. Baldauf, S. Sheikh & Thuin in its shorter height, very crowded when clustered, the curly smaller aggregations that may disperse into sparate mounds, smaller irregular spores with granules ( Figs. 11B , 12A, 12C ) and also the commonly occurring curly typical remnants of streams at the basal end of late sorogens and sorocarps. Lower sorophore prostrate and coremiform, mostly when clustered. When the culture becomes crowded, late aggregations and pseudoplasmodia interconnect with flat meandriform streams, which persist after the full development of clustered and solitary sorocarps ( Figs. 11B, 11E , 12B ), a condition similar to, but distinguishable from, what is observed in some strains of Raperostelium tenue (Cavender, Raper & Norberg) S. Baldauf, S. Sheikh & Thuin. Mature young solitary or clustered sorocarps appear with a small mass of pseudoplasmodium close to the base, and with one or more remaining ample flat streams at the sides, this is a cluster that occurs in early formation ( Figs. 11B, 11D, 11E ). Sorocarp height is variable when 2–5 branched sorocarps are in a cluster. Early sorogens may migrate briefly. A sorogen arises centrally when solitary but sometimes from the edges, elongated and curved (0.2 mm). Middle-late sorogens within a cluster rise up tightly joined, with abundant slime (0.3–0.6 mm, variable). Late sorogens are lageniform to club-shaped or with an acute tip, resuming soon to produce a fruiting body (0.5–0.7 mm) ( Figs. 11B, 11E , 12B, 12C ). Secondary branches (as monochasial) may be formed close to the base. Minute branches, less common, are formed after the installation of incoming late creeping myxamoebae ( Fig. 11E ). Spore dehiscence is longitudinal and the spore case divides into two thick valves ( Fig. 11J ). Under standard conditions, sori separate enough to form well dispersed curved sorophores, but in the twisted habit tangled sori are common. Sori may remain dry for long time or slip down the sorophore. Early sorogens may soon become partite. This small species is very adaptable to different conditions and the range of temperatures for activity is wide (15–28°C). Cultures remain stable for several weeks under dry and humid conditions.

Figures

FIGURE 3. Features of Cavenderia minima (Eden 1). A. Irregular small aggregation with few ample streams, the streams have lobular margins and ends, open to incoming myxamoebae; generally, one smaller stream appears surmounted over the body of the others, the center is elevated and granulose (above), three minute and irregular mound-like aggregations, with a flattened edge of incoming myxamoebae (below), B. A sequence of development of small solitary early sorogens from left to right, a very early sorogen rises up from the center of a cupuliform pseudoplasmodium, one to three old flattened streams appear as clouds of myxamoebae (left) and may remain until further development, a sorus-like, rounded terminus, sorogen may be formed (right), C. A tight cluster of sorocarps with a late small sorogen and a mature sorocarp with rising up tiny masses of pseudoplasmodia and slime (right), on the left a solitary decumbent marginal sorocarp has collapsed, with a stoloniferous habit; at the center a curved sorophore with no sorus; the relicts of three ample streams remain as clouds of myxamoebae and mucilage at bases, D. Two solitary unbranched sorocarps, straight prone with a globoid sorus (left) and a sorocarp with two curves of the sorophore, with a globose small sorus, bases inconspicuous but surrounded by granules, slime, and relicts of the pseudoplasmodia, E. Three bases with one tier of cells: clavate, with smaller terminal cell, the sheath is cone-like (left), curved, with a curved enlarged terminal cell (center), a base with its last four cells enlarged, showing the mucilage and a small mass of more dense and darker mucilage (right), F. Different simple one-celled tips: with an amorphous cell (left), three with an enlarged granulated cell and/or abundant slime (center), with a piliform elongated terminus (right); the last sorophore segment is always flexuous, most of tips are curved at the end, G. Myxamoebae with an enlarged vacuole, H. Elliptical irregular spores with clusters of consolidated and unconsolidated (spaced) granules mostly at poles, one cluster of granules is larger than the opposite one, halos are common around the clusters of granules, I. Spore break-line and the open spore capsule (below) in two halves. Bars:A–B = 50 μm, C–D = 100 μm, E = 15 μm, F = 3 μm, G = 10 μm, H–I = 6 μm.

FIGURE 4. Features of Cavenderia minima. A. Irregular shortly streamed aggregation, streams are ample, with lobular margins and ends, also open to incoming myxamoebae, B. Solitary unbranched, sometimes curved small sorocarps, at the top, a twisted late sorogens; sorocarps are mostly scarce and very small, hence the name C. minima, C. Short early solitary sorogens and the minute mound-like stage of the aggregations, a sorocarp has collapsed (bottom), D. Small elliptical irregular spores with polar to subpolar consolidated granules, generally the cluster of granules appears larger at one of the poles. Bars: A = 30 μm, B = 200 μm, C = 100 μm, D = 6 μm.

FIGURE 5. Features of Hagiwaraea tenebrica (ONG2). A. Irregular off-centered streamed aggregations, streams are broad, with lobular margins and ends, streams termina separate and can conform flattened tiny masses of pseudoplasmodia that surround the aggregation, streams also are open to incoming myxamoebae, the center is elevated, somewhat cupuliform, B. Condensed pseudoplasmodia from which arise solitary centered very early sorogens, at the basal part there are rudimentary streams (above, left), clustered early sorogens tightly joined, clustered early-late sorogens which separate (center, left), solitary late sorogen with the lower sorophore prostrate (center, right), solitary typically curved late sorogen; surrounding the base is a disrupted circle of mucilage and cells (below), C. Cluster of mature unbranched sorocarps, curved and straight, one of them decumbent with its sorus collapsed and with regrowth; sori globose, pigmented different from the sorophore and the crampon base, more obscure, D. Solitary erect sorocarp with its sorus and cramponated base and surrounded by tiny masses of pseudoplasmodia and slime, E. Crampon base immersed within its dense slime matrix full of large and small pigmented granules; the sheath is strong and attaches the structure to the substrate; the crampon base is of a darker tone of fuscus color, each crampon “root” shown is borne at a different level of the sorophore base with respect to the others and generally consists of one tier of cells; the crampon terminal “root” cell commonly clavate (left), the bases are encased in a slime sheath which is cone-like (above, left) and sometimes the base is positioned in a cavity on the substrate (center, right), a crampon base early in formation with protruding terminal cells (below, left), F. Two tips: a capitate tip with amorphous cells and flexuous subtip (above, left), a very thin one tier of cell terminus with its last section covered by a dense hyaline persistent slime that attaches undifferentiated unconnected small cells and many large and small pigmented granules, G. Microcysts, H. Spore capsule opens irregularly at the equator (left), dense myxamoebae with many dark granules (right), I. Elliptical irregular spores with polar to subpolar consolidated granules, some at the center of the spore body, of different sizes with vacuoles and heterogeneous content. Bars: A–B = 200 μm, C–D = 300 μm, E = 25 μm, F = 7 μm, G = 2 μm, H = 10 μm, I = 5 μm.

FIGURE 6. Features of Hagiwaraea tenebrica important for identification: A. Irregular off-centered streamed aggregations, the streams are broad, with lobed margins and ends, also with anastomosed termina, which then disrupt and form tiny masses of pseudoplasmodia that tend to surround the center, streams also open to incoming myxamoebae, B. Clustered (left) to solitary mostly unbranched sorocarps (right), sorocarps are gently curved, sori globose, one sorus has slid down a little, sorophores appear to be coremiform in part, branches few and very small, C. Main feature of the species is a crampon base immersed into its dense slime and pleated sheath, with visible dark large granules, the number of crampon “roots” is usually 4 or 5, characteristically incased in a slime sheath, D. Small elliptical-oblong spores with polar to subpolar consolidated granules, some large granules are also apparent in the spore body. Bars: A = 150 μm, B = 500 μm, C = 20 μm, D = 6 μm.

FIGURE 7. Features of Hagiwaraea irregularibrachiatum (Krug 6–5A). A. Streamed aggregation of thin streams and dense center, with short secondary unfinished streams (forked), sometimes anastomosed at the end, small circles are microcysts, B. Early (above) and later aggregations with elongated coremiform sorogens in a cluster (below), C. Mature cluster of whorled sorocarps (including a late sorogen), some appear coremiform (left), others are decumbent and become prostrate (right), abundant microcysts within and surrounding the cluster, D. Solitary branched sorocarp, each branch may hold 1 to 4 whorls, or two groups of few whorls, E. Four models of bases: clavate, of several rounded enlarged cells of a solitary sorocarp (above left), coremiform bases consisting of one tier of cells, these are very uniform and rest on a dark cushion of dense slime (above, right), curved base with a stolon also angled (below left), curved base with protruding cells and a dense matrix of slime; in all cases, sorophores above the basal termina consist of one tier of cells, F. Model of a whorl, with its node and two curved branches, one is broken, a collapsed cell sustained on the other side by a cellular mass and slime (left), G. Microcysts, H. Capsulated small and broad spores with polar to subpolar unconsolidated granules, sometimes granules are widely scattered within the spore body, also with tiny vacuoles. Bars:A–B = 100 μm, C–D = 200 μm, E–F = 20 μm, G = 4 μm, H = 6 μm.

FIGURE 8. Features of Hagiwaraea irregularibrachiatum important for identification. A. Regular radiate streamed aggregation of the “violaceum” type with thin regular sections of the streams and branched or anastomosed ends, abundant microcysts on the surface, B. Two late sorogens, with a small globular mass of psudoplasmodia below the terminus that will form the first whorl, C. Irregular broken sorophores and noded 3–4 whorled sorocarps, each whorled branch curved, D. Elliptical short spores with small unconsolidated polar to subpolar granules. Bars:A = 120 μm, B = 60 μm, C = 45 μm, D = 6 μm.

FIGURE 9. Features of Raperostelium cymosum (Krug 15A). A. Very small aggregations at different stage of progress, early-mature aggregation with very short flattened progressively expanded streams that may partitioned, streams are ample, with irregular ill-defined margins, sometime lobed, thin in height, unfinished and open to incoming myxamoebae (left), cupuliform pseudoplasmodium with a remnant of an expanded flattened stream (right), B. Three early tight clusters of sorogens, a common pair of sorogens (early and late sorogens) rise up at different times after resumption of the pseudoplasmodium formation (left), an early curved sorogen close to a branched late sorogen (center), a cluster with sorogens of different stages of development, one of them bent over drastically, along with a mature unbranched sorocarp, short lobed streamed pseudoplasmodia are common at base (right), C. Cluster of open branched and unbranched sorocarps with an early late sorogen, some minute pseudoplasmodial masses remain close to the cluster (right), D. Solitary unbranched sorocarp with lobules of pseudoplamodium and mucilage at the base, E. Tight cluster of unbranched, branched and rebranched sorocarps, in almost all cases sorophores are of different heights but decreasing from the oldest to the younger joined sorocarps; they are delicate, irregular, broken, with an expanded reticulate slimy basal part, at the point of breakage there are marginal tiny masses of slime and undifferentiated cells; also, there are minute ascending masses of pseudoplasmodia on these sorophores of one tier of cells, with abundant slime, one (or more) tightly joined early sorogens as is typical for this species, a secondary sorogen may ascend as a branch or not, sori are of different diameters, one branch has collapsed, giving rise to a new sorogen (below, right), most bases are surrounded by a halo, F. Three representations of bases: clavate, with several cells above a larger terminal cell (above, left), three one-celled bases with round to clavate terminal cells in touch with each other and resting on a darker dense discrete granular structure (center, left), a clavate base with protruding cells as crampons, within a dense and abundant slime, G. Group of very variable tips: with an amorphous flexuous terminal cell, with elongated or short piliform terminus, with an elongated curved cell, in most cases tips are simple, single-celled, curved, thin and with a dense matrix of sticky granulated slime (attached spores), H. Microcysts, I. Large elliptical, mostly reniform spores with conspicuous consolidated polar to subpolar granules, spores are also vacuolated and with heterogeneous content. Bars: A–C = 50 μm, D–E = 100 μm, F–G = 15 μm, H = 3 μm, I = 6 μm.

FIGURE 10. Features of Raperostelium cymosum important for identification. A. Minute aggregations at different stages of progress: early-mature aggregation with shortanastomosed streams that cover almost the whole area surrounding the centers (above, left), cupuliform, button-like pseudoplasmodium with a tiny very early sorogen (above, right), three closer late aggregations, almost mound-like, with one to three streams (below, right); streams are very short and ample, expanded, lobed, flattened progressively, inconspicuous and open at the end to incoming myxamoebae, B. Three tight clusters of sorogens, early curved, irregular sorogens that rise up in close contact each other, bend over and separate at tips, in this case, almost at the same time, C. Early and late solitary sorogens (above, right and left) and mature fruiting bodies tightly clustered; a majority of sorocarps have well separated sorophores and sori, one is coremiform (center, left), two clusters show the on-going production of early sorogens at base (below, left), sorophores are of different heights, delicate, irregular, curved, somewhat broken, sometimes branched, few in number; sori are globose, one sorocarp has a collapsed its sorus, D. Large elliptical, mostly reniform spores with conspicuous consolidated polar to subpolar granules. Bars: A = 50 μm, B = 50 μm, C = 350 μm, D = 6 μm.

FIGURE 11. Features of Raperostelium crispum (Eden 2). A. Asymmetrical small aggregation with typical curled, unfinished streams, curled streams anastomose soon after leaving clear areas, sometimes streams fork at acute angles and give the appearance of drastic change of direction, stream diameters vary from thin to very ample at any point of their length, leaving minute masses of streamed pseudoplasmodia progressively unconnected, the feeding front is conspicuous and continuously groups of myxamoebae migrate to larger streams or pseudoplasmodia (above), larger streamed pseudoplasmodia fragment at the periphery, leaving behind a number of pseudoplasmodial masses, which become irregular mounds, the entrance of myxamoebae is constant in the smaller mounds (below), B. Early (left) and late (right) sorogens in clusters, two of them rise up with a coremiform habit (right), the curled streamed basal pseudoplasmodia persist when mounds are not formed, C. Three models of basal section of late sorogens: with striated sheath (left) and with an ample slime mass (center, right), all with halos of myxamoebae, D. Young solitary unbranched sorocarp, the sorophore consists of one tier of cells, untapered, a tiny blob tightly joined to the base is a very early sorogen, almost round, two or three clouds of myxamoebae are the relicts of streams, E. Tightly clustered sorocarps with the typical curled streams at their bases, these formations are several times curved and sometimes parallel with each other, sorophores are curved, broken, sori globose, of different diameters, that may slide down; bases are also covered by lobed slime, masses of rising pseudoplasmodia settle at different points of the sorophore and form small to large branches at acute or right angles, F. Four models of bases: multicellular clavate (above, left), three bases of one tier of cells in a cluster with their curved termina in contact and resting on a dense darker slime mass (above, right), a multicellular base with protruding cells, with strong crampon of sheath (left, below), a base with a bifid terminus on a cushion of darker, dense slime and some undifferentiated cells (below, right), G. Very thin terminal segments with amorphous flexuous capitate cells (left) and piliform cells (right), in most cases with sticky slime, H. Myxamoebae, I. Small short elliptical oblong spores with consolidated granules at the poles and subpolar, heterogeneous content with small granules and vacuoles within the spore body, J. Spore case in two longitudinal halves. Bars:A–E = 150 μm, F–G = 15 μm, H = 10 μm, I–J = 5 μm.

FIGURE 12. Features of Raperostelium crispum important for identification. A. Irregular asymmetrical small aggregation with typical curled, unfinished streams, streams soon anastomose, leaving very small empty areas that sometimes give the appearance of acute angles; stream diameters vary from very thin to relatively wide at any point of their length, leaving minute masses of streamed pseudoplasmodia progressively isolated (above), larger streamed pseudoplasmodia fragment and form irregular close, sometimes connected, mounds, the peripheral ones are open to incoming myxamoebae (below), B. Clustered and solitary sorocarps with the remaining expanded formation of curled streams at their bases, often streams are annular, sorophores are curved, broken, sori globose, small to large, C. Two late pseudoplasmodia with a very early sorogen (right) and with a bifid early-late sorogen (left), small pseudoplasmodia that surround the main mass soon condense into mounds, D. Small short elliptical or oblong spores with consolidated granules at the poles. Bars: A = 40 μm, B = 300 μm, C = 150 μm, D = 6 μm.