Palhinhaea Franco & Vasc.

Øllgaard, Benjamin & Testo, Weston, 2021, The Lycopodiaceae of Panamá, Phytotaxa 526 (1), pp. 1-66 : 51-52

Palhinhaea Franco & Vasc. in Vasconcellos & Franco (1967: 24)

Type:— Palhinhaea cernua (L.) Vasc. & Franco (≡ Lycopodium cernuum L.).— Lycopodiella sect. Campylostachys (K. Müller) Øllgaard (1987: 175).— Lycopodium sect. Campylostachys Mu ̈ller (1861: 163).

Lycopodium subgen. Rhopalostachya Pritzel sect. Cernua Pritzel (1901: 602) . Type:— Lycopodium cernuum L.

Palhinhaea Franco & Vasc. was proposed to be conserved over Lepidotis P.Beauv. ( Greuter & Troia 2014) ; the proposal was later accepted ( Applequist 2016).

Sporophytes with trailing or arching to looping indeterminate shoots that root with usually long intervals and occasionally branch in the horizontal plane, giving off horizontal branchlet systems,-and usually bearing one main erect branch arising on the dorsal side of the loops; the main erect branch bears a series of subdecussately arranged, spreading to hanging, flabellate branchlet systems, which in turn may terminate in sessile, nodding to pendulous strobili. Palhinhaea steyermarkii is unusual because of the long, slender, scandent, climbing, or creeping main axes, which give off spreading to flaccidly hanging lateral branchlet systems. Also P. glaucescens (Northern Andes) and P. lehmannii (Northern Andes and Panamá) usually have scandent growth. Leaves and stem surfaces often with short, unicellular or pluricellular and branched hairs. Sporangia partly enclosed in cavities formed by the strobilar cortex and the coalescent basal membranes of adjacent sporophylls (Fig. 1C), subglobular, anisovalvate. Sporangium epidermis cells with nodular or buttress-like, lignified thickenings on the straight side walls; spores rugate to nearly smooth, without a distinct equatorial rim.

Pantropical genus, commonly pioneers on disturbed soil. Palhinhaea cernua is pantropical and by far the most widespread species. Most other species have narrow distributions. Ca. 20 species in the Neotropics. Species diversity is especially high on tropical mountains. Palhinhaea steyermarkii may grow as a high-climbing epiphyte.

1. Dorsally arising strobiliferous shoot systems tree-like, the main erect stems usually erect, (2.5–) 3–5 mm thick excl. leaves, glabrous or hairy, terrestrial...................................................................................................................................................................................2

2. Branchlet leaves imbricate, distinctly flattened, lanceolate-ovate, with densely fimbriate margins .................................. 5. P. riofrioi

2. Branchlet leaves spreading to ascending, terete, angular or apically flattened, acicular to linear-lanceolate, smooth or with distant cilia or pointed hairs. ....................................................................................................................................................................3

3. Leaves of main branches of dendroid erect shoots hair-like, patent to upward curved or recurved, acicular and angular (dried), usually 3–4 × ca 0.3 mm. ...................................................................................................................................... 1. P. cernua

3. Leaves of major dendroid erect shoots appressed or sharply reflexed, flattened, 0.5–1 mm wide. ...............................................4

4. Leaves at least of lower part of main branches of dendroid erect shoots closely appressed, upward partly diverging and apically inward curved. Ramification angles of branchlet systems less than 90°................................. 2. P. cerrojefensis

4. Leaves of dendroid erect shoots and major branchlets sharply reflexed and usually more or less sigmoid. Ramification angles of branchlet systems commonly more than 90° ........................................................................................ 3. P. divaricata

1. Dorsally arising strobiliferous shoot systems slender, not tree-like, with age becoming long scandent or pendulous, glabrous or hairy.

5. Plants usually epiphytic ( Panamá). Main stems glabrous, usually with appressed leaves. Strobili to 9 cm long, ca 4 mm thick (with appressed sporophylls). Sporophylls with 4–5 × 1–1.5 mm exterior face. ........................................................ 6. P. steyermarkii

5. Plants terrestrial, scandent. Main stems hairy, with ascending to reflexed leaves. Strobili variable, 7–20 mm long, 2–3 mm thick. Sporophylls with 1.5–2 × ca. 1 mm exterior face. ................................................................................................. 4. P. lehmannii