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A new Genus, Zyzyura is named to accommodate Fleischmannia mayana Pruski that has an eximbricate involucre, a high-conical receptacle, a corolla with a slender base closely investing the style and with a broadly campanulate limb, enlarged elongate cells in the carpopodium, short and broad distally protruding cells in the corolla lobes, and broad rounded anther appendages.
Zyzyura, New Genus, Fleischmannia, Eupatorieae, Belize
The recent description of Fleischmannia mayana Pruski (
The concept of Fleischmannia Sch.Bip. has been well established since the redefinition of the limits of the genus (
Four characteristics of Fleischmannia mayana are inconsistent with the characters that define Fleischmannia or even its only recognized close relative, Sartorina R.M.King & H.Rob. (1987).
The involucre of the Belize species is eximbricate with mostly 2 series of equal, obovate bracts with broadly rounded tips (Fig. 2C). While Fleischmannia often has the superficial appearance of being eximbricate, an appearance allowed for in many keys (
The receptacle of the Belize species is highly conical as seen in two heads in which the receptacle shows without dissection (Fig. 1C), while that of Fleischmannia is plane to scarcely convex.
The corolla has a basal tube closely investing the style and an abruptly expanded campanulate limb, differing from consistently funnelform shape in Fleischmannia.
The carpopodium of the Belize plant has enlarged and elongate cells (Fig. 1F), a feature different from the smaller subquadrate cells in Fleischmannia.
There are a few more subtle distinctions from Fleischmannia:
The anther thecae are very short, and the apical anther appendages are slightly broader than long (Fig. 1E).
The cells of the corolla lobes are shorter and broader than those of Fleischmannia (Fig. 1D)
The pappus bristles are ca. ten in number and separated at the base (Fig. 2), a feature true of some Fleischmannia, but the bristles of the pappus are broad at the base unlike those in the Fleischmannia species which have five or ten non-contiguous bristles.
A few features are similar to those of Fleischmannia: the cells of the corolla lobes project at their distal ends on both surfaces of the lobes (Fig. 1D), the anther collars are very narrow and strongly transversely annulated, though the annulations do not completely obscure the crosswalls of the cells in the collars, the cells of the carpopodium have reasonably thick walls, and the style bases are neither enlarged nor papillose.
The most striking feature of the new genus is the high-conical and fistulose receptacle (Fig. 1C). How this structure functions is hard to determine, since there is no evidence of raised central florets in the flowering heads on the holotype. Careful examination of the photographs, however, shows a central cluster of corolla-like material and a possible exposed tip of receptacle in the center of the cluster (Fig. 1B). It seems possible that florets never fully develop on the distal part of the receptacle.
The position of the Belize species in the Eupatorieae is not resolved. Although a number of features are shared with Fleischmannia, and the two may have some phylogenetic relationship, the distinction of the species from anything in Fleischmannia is now certain. Furthermore, the new genus, cannot be placed in any of the other genera presently recognized in the tribe. It is particularly notable that few members of the Eupatorieae have a highly conical receptacle: Isocarpha R. Br. in which the receptacle is paleate, and Praxelis Cass, and Eupatoriopsis Hieron., both members of the subtribe Praxelinae, that have completely deciduous involucral bracts. The latter two also have 3-costate or obcompressed achenes.
In the general key to all the Eupatorieae genera in
Differs from Fleischmannia by the conical and fistulose receptacle, the eximbricate rather ‘Piquerian’ involucre, the slender-based corolla with broadly campanulate limb, and elongate cells of the carpopodium.
Fleischmannia mayana Pruski.
Decumbent epilithic herbs rooting at proximal nodes, prostrate portions 5–20 cm long, with short internodes, mostly glabrous, ascending portions 15–30 cm tall, with few small hairs, with long basal internodes; stems narrowly fistulose. Leaves (Fig. 1A) opposite, petioles mostly 3–5 mm; blades deltate in outline, mostly 4–7 mm long and wide, 3-7-lobed with sinuses 1/3-1/2 to midvein, basal margin truncate or subtruncate, triplinervate at base, margins of lobes often slightly notched, sparsely pilose adaxially, paler and hairless with crowded glandular dots abaxially. Inflorescence (Fig. 1B) terminal on ascending portions, ascending parts not branched below, distally loosely branching with 3–10 capitula, with few minute opposite to subopposite bracteoles; peduncles mostly 0.5–1.8 cm long. Capitula discoid, broadly hemispherical, to 7 mm high and wide; involucres (Fig. 1C) eximbricate; bracts c. 16 in mostly 2 series, subequal, obovate, with obtuse to rounded tips, chartaceous-becoming more scarious distally, bicostate proximally, few shorter outer bracts, scarcely spreading at maturity, essentially glabrous; receptacle (Fig. 1C) high-conical, fistulose, epaleate, without evidence of fully developed florets born on distal part. Florets 20–23; corollas white, 2.2–2.3 mm long, mostly glabrous, sparse glandular dots on lobes, immediate base dilated, thickly ribbed, narrowed to a slender tube closely investing the style, limb abruptly ampliate, campanulate, lobes (Fig. 1D) deltate, with intermarginal ribs, cells projecting at distal ends on inner and outer surface; anther collars slender, with numerous annular thickenings that do not completely obscure transverse cell walls; anther thecae (Fig. 1E) c. 0.5 mm long; apical appendage slightly broader than long. Style base without expanded node, papillae or hairs, style appendages thickened, densely papillose. Cypsela (Fig. 2) 1.2–1.3 mm long, somewhat fusiform, 3–5 costate, with few scabrae on ribs; carpopodium (Fig. 1F) broadened, with distinct projecting upper rim, cells enlarged and elongate with moderately thickened walls; pappus iniserate (Fig. 2) with c. 10 persistent capillary bristles, reaching to approximately the base of corolla lobes, broadened but not contiguous at base, scabridulous, narrowed to apex. Pollen c. 18 μm in diam. in fluid.
Zyzyura mayana (Pruski) H. Rob. & Pruski, A Prostrate portion of living plants showing lobed leaves B Capitula on erect flowering branches of living plant showing denser floral material near centers of capitula C Capitula of pressed specimen, lower capitulum showing eximbricate involucral bracts, upper head split, showing conical fistulose receptacle, upper capitulum also showing loose corolla D SEM of corolla lobes showing surfaces with protruding cells E Anther showing short theca and broad apical appendage F SEM micrograph of carpopodium showing elongate cells. (All from Brewer & Pau 3349)
Zyzyura mayana, cypsela showing pappus of c. 10 non-contiguous bristles. (From Brewer & Pau 3349)
The genus contains only the single species that may be endemic to the type locality in the Maya Mountains of the Cockscomb range in Belize.
Cited as epilithic.
Contrived name (no meaning).
Zyzyura mayana (Pruski) H. Rob. & Pruski, comb. nov. (IPNI ID: urn:lsid:ipni.org:names:77124264-1), basionym: Fleischmannia mayana Pruski in Pruski and Clase, Phytoneuron 2012-32: 6. 2012. Presently known only from Victoria Peak in the Cockscomb range of the Maya Mountains in Belize (Brewer & Pau 3349, holotype MO).
Steven W. Brewer is thanked for providing the material of the new genus and his field photographs of the living plants. Carol Kelloff of the Department of Botany, NMNH, is thanked for operating the SEM. James Di Loreto, Smithsonian, National Museum of Natural History Imaging is thanked for the close-up photographs of the capitula, Alice Tangerini of the Department of Botany, NMNH, is thanked preparation of the plates. The Missouri Botanical Garden is thanked for the loan of the holotype specimen to the Department of Botany, National Museum of Natural History, Smithsonian Institution. We also thank two anonymous reviewers and the Editor for their useful suggestions.