Hypolepis Bernh., Neues J. Bot.

Schwartsburd, Pedro B., Navarrete, Hugo, Smith, Alan R. & Kessler, Michael, 2017, Prodromus of a fern flora for Bolivia. XXVI. Dennstaedtiaceae, Phytotaxa 332 (3), pp. 251-268 : 255

Hypolepis Bernh., Neues J. Bot. 1(2): 34. 1805 [1806].

Hypolepis has creeping, solenostelic rhizomes, 2-to 5-pinnate blades, and marginal or submarginal sori, each served by one vein and in some species covered by the recurved laminar margins (pseudo-indusia). Several species have aculeate petioles, and catenate, glandular hairs are common in the genus. Dennstaedtia differs by having cup-shaped sori, and Paesia by elongate sori, served by 2–4 veins and protected by inner and outer indusia. Some species of Ctenitis , Megalastrum (both Dryopteridaceae ), and Macrothelypteris ( Thelypteridaceae ) have similar blade architecture, and may be confused with Hypolepis , but in those genera the rhizomes are erect to decumbent and clothed with scales (vs. creeping and clothed with catenate hairs), and the sori are abaxial (vs. marginal or sub-marginal). Hypolepis falls in the “ Hypolepidoideae ” clade within the Dennstaedtiaceae , sharing common ancestry with Blotiella , Histiopteris , Paesia , and Pteridium ( Schuettpelz & Pryer 2008, Perrie et al. 2015).

The epidermal outgrowths on the petioles of many species of Hypolepis are not vascularized and thus, technically speaking, are aculei or prickles. However, we use the term spines (technically referring to vascularized structures) because of its familiarity to a non-specialized readership.

Several species commonly grow so densely in natural treefall gaps as to suppress tree regeneration ( Kessler 1999), but unlike Pteridium , they usually do not present problems in human-disturbed habitats. Hypolepis is a subcosmopolitan genus of perhaps 80 species (PPG I 2016), with about 40–45 in the Neotropics ( Proctor 1985, Moran 1995, Mickel & Smith 2004, Schwartsburd & Prado 2015, 2016). Schwartsburd & Prado (2015, 2016) recently reviewed the South American taxa and recognized nine species in Bolivia. We here recognize 12 species and one variety, revalidating H. minima and H. buchtienii (as H. rigescens var. buchtienii ), and describing two new endemic species ( H. periculosa and H. woodii ). These four taxa are illustrated here ( Figs. 1 , 2 ); the other nine are illustrated in Schwartsburd & Prado (2015, 2016).

Figures

FIGURE 1. A–D. Hypolepis woodii (Solomon 16418): A. Proximal pinna, B. Detail of petiole and rachis, abaxially, C. Ultimate pinnule, abaxially, D. Detail of veins, sori and pseuso-indusium, abaxially. E–G. Hypolepis periculosa (Kessler 12087): E. Detail of petiole and rachis, abaxially, F. Pinnule, abaxially, G. Detail of veins, sori and pseuso-indusium, abaxially.

FIGURE 2. A–D. Hypolepis rigescens var. buchtienii (Buchtien 7014): A. Habit, B. Detail of petiole and rachis, abaxially, C. Pinnule, abaxially, D. Detail of veins, sori and pseuso-indusium, abaxially; E–H. Hypolepis minima (Jimenez 972): E. Habit, F. Detail of petiole, abaxially, G. Medial pinna, abaxially, H. Detail of veins, sori and pseuso-indusium, abaxially.