Maschalostachys Loeuille & Roque, 2017

Loeuille, Benoît & Roque, Nádia, 2017, Maschalostachys, a new genus of Vernonieae (Asteraceae) from Brazil, Phytotaxa 295 (1), pp. 35-48 : 38

Maschalostachys Loeuille & Roque , gen. nov.

Type:— Lychnophora markgrafii Barroso (1956: 260) = Maschalostachys markgrafii (Barroso) Loeuille & Roque.

Genus similis Paralychnophorae vaginis foliosis semiamplexicaulibus, capitulis in syncephalis aggregatis et pappo biseriali sed indumento pilis T-formibus et pilis simplicibus compositis (nec pilis 3–5-brachiatis) et inflorescentia spicis syncephalorum vel paniculis spicarum syncephalorum (nec syncephalis solitariis) differt.

Treelets. Stems monopodial, initially leafy, later becoming leafless, with transverse linear leaf-scars following leaf shedding. Leaves alternate or in pseudo-rosette at the apex of stems, simple, sessile or petiolate, with semi-amplexicaul leaf sheath, venation eucamptodromous, margin flat. Capitula fused in a syncephalium (secondary order inflorescence) surrounded by secondary leafy bracts and organized in loose axillary spikes or frequently in a panicle of spikes (rarely a cyme); flowering branch inconspicuously sulcate, flexuose, persistent. Capitula homogamous, discoid, sessile, surrounded by 1–6 spatulate subinvolucral bracts; phyllaries 5–6-seriate, apex slightly acute or obtuse, usually shortly mucronate, brown or green, tomentose; receptacle flat, glabrous. Florets bisexual, fertile; corollae actinomorphic, deeply 5-lobed; apical anther appendages lanceolate, acute, anther base sagittate; style shaft glabrous throughout except for pubescence beneath style-arms, style-arms apex acute, pubescent outside, hairs acute, style-base glabrous, lacking basal node. Cypsela cylindrical or obconic, angled, 10-ribbed, carpopodium annuliform, inconspicuous; pappus biseriate, outer series smaller than inner series, paleaceous, persistent, apex acute, erose, base somewhat enlarged, inner series sub-paleacous, caducous or deciduous.

Chromosome number: —The chromosome number is n = 19 ( M. markgrafii ) ( Mansanares et al. 2007).

Phytochemical data: —Characteristic sesquiterpene lactones guaianolide and furanoheliangolide have been identified from M. markgrafii ( Sartori et al. 2002) .

Etymology: —The name means axillary spike in transliterated greek (μασχάλη - maschalo- axillary; στάχυς - stachys - spike).

Distribution and habitat: — Brazil ( Bahia and Minas Gerais states) ( Fig. 3 ). Both species of Maschalostachys are restricted to the northern portion of the Espinhaço Range of mountains in Bahia and Minas Gerais states. They are remarkably common treelets in a particular phytophysiognomy called caatinga rupestre. This vegetation occurs in transitional areas between the Cerrado and Caatinga domains and shows xeromorphic aspects, with numerous rocky outcrops, shallow soils and predominance of herbs and shrubs (rarely trees) up to 3 m tall, occurring at elevations of 750 to 1000 m high. Its floristic composition and lower elevations are major features distinguishing it from campos rupestres, the most widespread vegetation along the highlands of the Espinhaço Range ( Campos et al. 2016).

Figures

FIGURE 3. Distribution of Maschalostachys markgrafii (red star) and M. mellosilvae (blue circle)