Cryptochloa stapfii Baldini & O. Ortiz, 2015

Baldini, Riccardo M. & Ortiz, Orlando O., 2015, Cryptochloa stapfii (Poaceae: Bambusoideae: Olyreae), a new neotropical herbaceous bamboo from Panama, Phytotaxa 203 (3), pp. 271-278 : 273-276

Cryptochloa stapfii Baldini & O. Ortiz , sp. nov. ( Figs. 1–2 )

A C. dressleri foliis intense viridis, raro purpureis, linearis angustatis, et maturitatem dispositione lemmatatum florum femineorum ad basim nunquam mutue supraimposita, filamentibus antherarum longioribus.

Type:— PANAMA. Bocas de Toro, Camino Rambala-Platanarito, E de Rambala, área semi-sombreada, 8 ° 55’28”N 82 ° 09’53”W, 85 m, 21 January 2012, M. S. Stapf, R. M. Baldini R. & O. O. Ortiz 865 (holotype PMA!, isotypes FT!, MO!, SCZ!).

Perennial, short-rhizomatous, delicate, 5–15(–20) culms, 20–40 cm tall. Leaves narrowly lanceolate, green, rarely purplish, 3–7 cm long, 0.3–0.6 cm wide, ligule truncate, glabrous, prominent, 5.5–6 mm long. Monoecious. Inflorescences paniculiform, 2–3 at the upper nodes of each terminal leaf, simply exserted, generally sticking along the axis, with 1 terminal female spikelet and few lateral spikelets with 1 branch of 3– 5 male spikelets, borne in the lower part of the rachis, or at the end of the inflorescence. Female spikelet: glumes green, glabrous, scabrous at the margin, lower glume glabrous, 9–11(–11.5) mm long, aristate, awns up to 2.5 mm long, upper glume acuminate, 8–10 mm long. Lemma 8–9 mm long; palea narrowly ovate, 2-nerved, acute at the apex, margins not folding toward at the base at maturity; lodiculae 3, sometimes reduced to 2, glabrous, slightly coriaceous. Male spikelets: deciduous after anthesis, glumes lacking, lemma glabrous, elliptic, linear not curved at the apex, palea glabrous; lodiculae 3, fleshy; stamens 2, anthers basifixed, 2 mm long, filaments 0.8–2 mm long. Fruit: caryopsis, elliptic.

Etymology:— This species is dedicated to Maria Stapf, expert botanist of the Flora of Panama.

Distribution:— Cryptochloa stapfii is known only from the type locality on Bocas del Toro ( Panama), around Chiriquí Grande and its surroundings ( Fig. 3 ).

Habitat and Ecology:— This species is present in moist forest remnants on steep slopes, in semi-shaded areas ( Fig. 4 ). Cryptochloa stapfii grows in an area of very wet tropical forest according to the classification of zones proposed by Holdridge et al. (1971), in association with Miconia ampla Triana (1871: 10 , Melastomataceae ), Neonicholsonia watsonii Dammer (1901: 179 , Arecaceae ), Calyptrogyne pubescens de Nevers (1995: 336 , Arecaceae ), Ichnanthus pallens ( Swartz 1788: 23) Munro ex Bentham (1861: 414 , Poaceae ) and Arberella lancifolia Soderstrom & Zuloaga (1985: 25 , Poaceae ) and others species of the Arecaceae family.

Phenology:— Flowering and fruiting throughout the year, with a peak in the dry season (January – March).

Conservation status:— This species is notable for its reduced geographical range and small population size. It is endangered, being not yet protected and subjected to habitat degradation as a result of the forest cutting and agricultural activities in its area of distribution. We suggest it be considered in the CR B2ab(iii) category according to the IUCN Red List Criteria ( IUCN 2001).

Additional specimens examined (paratypes):— PANAMA. Bocas del Toro, hill just S of Chiriquí Grande , at end of pipeline access road 2 mi N of 2nd large bridge N (10 mi) of continental divide, in forest along ridge & draws, 350 – 500 m asl, 8°54’N 82°10’W, 10 March 1986, Hammel, McPherson & Sanders 14746 ( MO, PMA) [this specimen bears a comment by G. Davidse ( MO) about its unusual leaf morphology] ; Carretera hacia Chiriquí Grande, Rambala , Platanarito , 8°55’28”N, 82°90’53”W, 2 February 2014, Ortiz, Baldini & Galdames 1995 ( BM, FT, K, PMA) .

Discussion:— Cryptochloa stapfii is an endemic species closely related to C. dressleri , with which it shares the presence of two rather than three stamens as in the rest of the species in the genus ( Soderstrom 1982a). Cryptochloa stapfii differs from C. dressleri in its narrow green leaves, not deeply purplish as in C. dressleri . Soderstrom (1982a) discussed the role of the purplish color of leaves in tropical plants, especially in herbaceous bamboos, in enhancing the capture of light in shaded habitats ( Lee et al. 1979). While Cryptochloa dressleri has this feature, in accordance with its typical shaded habitat, C. stapfii , with green leaves, seems to have evolved a different adaptation to the semi-shaded habitats to which it is restricted along the edge of the mist forest, where it receives more intense sunlight. During three years of field observations in Bocas del Toro area of five different populations at different times of the year, C. stapfii always showed the same green coloration. The main morphological distinguishing features in C. stapfii and C. dressleri are given in the Table 1.

During our field trips in Panama, we have observed that small dipteran insects visit some herbaceous bamboos (i.e., Arberella lancifolia , Pariana argentea Hollowell & Davidse in Davidse & Pohl 1992: 98) and presumably also species of Cryptochloa , confirming the role of insect pollination in the herbaceous bamboos ( Soderstrom & Calderón 1979). However, the role of insect pollination in Cryptochloa needs more evidence to be accepted. The presence of elaiosomes confirms and enforces the role of ants in fruit dispersal in the new species ( Davidse 1987, Bronstein et al. 2006, Lengyel et al. 2010). Dispersal of diaspores via elaiosomes has also been suggested for some panicoid genera ( Davidse 1987), including genera occupying the same habitat as Cryptochloa , including C. stapfii , such as Ichnanthus Palisot de Beauvois (1812: 56) . Species in the bamboo tribe Olyreae are monoecious with very reduced male spikelets, while the female spikelets are frequently and clearly modified, with an elongated and solid internode present between the glumes and the floret. This internode is made of a tissue that produces oils at fruit maturity, and has a function similar to an elaiosome ( Davidse 1987, Judziewicz 1990). The elaiosomes of C. stapfii and C. dressleri ( Fig. 4 , cf. Table 1) differ (papillate vs. not papillate), and this feature may be worth investigating more carefully throughout the genus as a source of taxonomic characters.

Comparative leaf morphology between C. dressleri and C. stapfii clearly shows some differences ( Fig. 5 ), such as the absence of prickles on the abaxial leaf surface in C. stapfii , and their presence in C. dressleri ( Jaén et al. 2013, Jaén 2014). The siliceous bodies in the adaxial leaf surface are reticulately arranged in C. dressleri and linear in C. stapfii . Discovery of C. stapfii brings the number of species of Cryptochloa in the Flora of Panama to eight ( Table 2), considering the present unresolved taxonomical status of C. granulifera Swallen in Woodson & Schery (1942: 321). The exact number of the species in the entire genus will only be known upon completion of an on-going taxonomical revision of the genus by us.

Figures

FIGURE 1. Cryptochloa stapfii Baldini & Ortiz: Panama, Bocas del Toro, M.S. Stapf 865, R.M. Baldini R. & O.O. Ortiz (from holotype, PMA). A. Habit, basal part. B. Habit, upper part with slender inflorescences. C. Female floret (ventral view). D. Female floret (dorsal view). E. Lower glume of female floret. F. Upper glume of female floret. G. Lemma of male floret. H. Stamens. I. Palea of male floret. L. Basal leaf blade with ligule. Illustration by Anne Maury.

FIGURE 2. Cryptochloa stapfii Baldini & O. Ortiz, in its habitat at the type locality (Panama: Bocas del Toro, Camino Rambala- Platanarito, E de Rambala) Photo: Riccardo M. Baldini.

FIGURE 3. Distribution of Cryptochloa stapfii Baldini & Ortiz in Panama. Star: type locality (holotype). Square: Paratype, B. Hammel, G. McPherson & L. Sanders 14746 (MO, PMA).

FIGURE 4. Rachillas of the internode of the anthecium (elaiosomes).A. Cryptochloa dressleri B. C. stapfii.

FIGURE 5. Comparison of leaf morphology between Cryptochloa dressleri and C. stapfii.A. C. dressleri, adaxial leaf surface, with linear rows of bulliform cells (large arrow), and crenate (olyroid) silica bodies (CreSB). B. C. dressleri, abaxial leaf surface, with prickles (large arrow), crenate (olyroid) silica bodies (CreSB), and cruciform silica bodies (CruSB). C. C. stapfii, adaxial leaf surface with irregular rows of bulliform cells (large arrow) and crenate (olyroid) silica bodies (CreSB). D. C. stapfii, abaxial leaf surface without prickles, crenate (olyroid) silica bodies (CreSB), and cruciform silica bodies (CruSB). Specimens: C. dressleri (Stapf et al. 785, FT, PMA, SCZ), C. stapfii (Stapf et al. 865, FT, PMA, SCZ).