Palhinhaea, Franco & Vasc.

Øllgaard, Benjamin, Boudrie, Michel & Cremers, Georges, 2020, The Lycopodiaceae of Guyana, Suriname, and French Guiana, Phytotaxa 433 (2), pp. 101-134 : 107

3. PALHINHAEA Franco & Vasc. , in Vasc. & Franco, Bol. Soc. Broter. II, 41: 24. 1967.— Type: Palhinhaea cernua (L.) Vasc. & Franco (= Lycopodium cernuum L., Sp. Pl. 2: 1103. 1753).

= Lycopodium subgen. Rhopalostachya Pritzel sect. Cernua Pritzel, Nat. Pflanzenfam. 1(4): 602. 1901, p.p.

= Lycopodium subgen. Cernuistachys Herter, Bot. Jahrb. 43: Beibl. 98: 29. 1909.

= Lycopodium sect. Campylostachys Müll. Berol., Bot. Zeit. 19(24): 163. 1861.

= Lycopodiella sect. Campylostachys (Müll. Berol.) B.Øllg., Opera Bot. 92: 175. 1987.

Sporophytes with trailing to arching or 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 every loop. 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). Leaves and stem surfaces often with short, unicellular or pluricellular and branched hairs. Sporangia almost enclosed in cavities formed by the strobilar cortex and the coalescent basal membranes of adjacent sporophylls, subglobular, anisovalvate. Sporangium epidermal cells unlignified but with nodular or buttress-like, lignified thickenings on the sidewalls. Spores rugate to nearly smooth; n = 104, 108, 110, 136, 156, c.165, 208.

Moist tropics, commonly pioneers on disturbed soil. Palhinhaea cernua is pantropical. Most other species have narrow distributions. 16–20 species in the Neotropics. Species diversity is especially high on tropical mountains. Palhinhaea steyermarkii may grow as a high-climbing epiphyte. Species diversity seems to be higher in this group than commonly assumed.

Most species have erect, dendroid branch systems arising from the dorsal side of horizontal, looping and rooting indeterminate axes, but in some species the corresponding dendroid branch system is scandent, hanging, or creeping. In these cases the dendroid branch system can be distinguished from the horizontal branch system by the orientation of lateral branchlet systems on the main axes. In the horizontal system they are distichous, all arranged in the horizontal plane. In the dendroid branch system the lateral branchlets are arranged in an irregularly subdecussate manner.