Paepalanthus caryonauta Hensold, 2016

Hensold, Nancy, 2016, The Andean Paepalanthus pilosus complex (Eriocaulaceae): a revision with three new taxa, PhytoKeys 64, pp. 1-57 : 14-20

1. Paepalanthus caryonauta Hensold sp. nov. Figs 2B-C , 3A , 4 , 5

Diagnosis.

Cushion plants with linear glabrescent leaves 1-2 cm long, rounded at the tip, or if cuspidate, the tip strongly deflexed. Peduncles ca. 9-25 mm, solitary, terminal at initiation, sheaths lacerate at apex, eciliate. Pistillate flowers in outer whorl of capitulum, the sepals broad, persistent, together with the petals enclosing the mature fruit at dispersal, nectaries uniformly dark brown, rigid. Staminate flowers central, with sepals fused ¼-¾ of their length.

Type.

PERU. Cuzco: Dist. Huayopata, sector San Luis , bosque primario intervenido, 13°04'S, 72°23'W, ca. 3000-3500 m, 24 Nov 2006, L. Valenzuela et al. 8117 (holotype: F; isotypes: AMAZ n.v., CUZ n.v., HUT n.v., MO, MOL n.v., USM n.v.) .

Description.

Densely branched cushion plants, the cushions reported to reach one meter in diameter (Dudley 11194), and 15 cm high (Barclay 5176). Branchlets 1-5 cm, densely and uniformly leafy. Leaves linear-subulate, 10-20 mm long including the open basal sheath 3-4 mm long, 1.2-1.7 mm wide at midpoint, ca. 2.5 mm wide at ampliate base; apex narrowly obtuse to rounded, if sharp-cuspidate the tip deflexed downward and not evident in adaxial view; inconspicuously appressed-pilose (rarely ciliate) in juvenile state, glabrate at maturity except for the irregularly ciliate basal sheath; "dark green and glossy" when fresh (Dudley 11060), chartaceous to subcoriaceous, the adaxial surface smooth, the abaxial surface often with margins prominently thickened in older leaves and 1-3 veins more or less salient. Inflorescences solitary and terminal, with one to four produced in succession along a sympodially branched axis, the lower appearing axillary. Peduncles (7-) 9-25 (-35) mm long, ca. 3-costate, obscurely angled, pale, glabrous to obscurely appressed-puberulent, usually with a collar of longer silvery hairs at apex investing base of involucre. Peduncle sheaths (9-) 10-17 (-25) mm long, equaling or surpassing the leaf mat by up to 5 mm, the lamina (tip) of the sheath 3-4 mm long, inflated, scarious, somewhat cucullate, almost closed at the apex in bud before emergence of capitulum, tufted-ciliolate at apex when young, often glabrate, frequently splitting into 3 triangular segments with emergence of capitulum. Capitula 3-4 mm in diameter. Involucres subequaling flowers at anthesis; involucral bracts 2-3-seriate, the outer bracts triangular-ovate to broadly ovate, dull gold, tinged gray or occasionally blackish on shoulders; the inner bracts usually more strongly pigmented except for the paler midvein; bracts bearded apically especially along upper midvein, the upper margin short-ciliate with proximal cilia slightly longer, often early glabrate abaxially. Bract and floral trichomes obtuse to clavate, subhyaline, obscurely ornamented within and very obscurely tuberculate. Flowers about 8-14 per capitulum, the pistillate flowers peripheral, the staminate central, equalling to subequalling the pistillate in number; the receptacle sparingly pilose or pilose only toward center. Receptacular bracts equaling to subequaling flowers, broadly linear-subspatulate, ca. 6 times longer than wide, the apex often slightly cucullate and pubescent as the sepals, the base distinctly carinate, clasping. Pistillate flowers: Pedicels ca. 0.1-0.35 mm, thick, glabrous, often becoming callose-thickened in fruit (Peru), leaving characteristic ‘stumps’ on the empty receptacle after abscission of flowers. Sepals broadly obovate, strongly cymbiform, with apex convex-acute to obtuse (1.35-) 1.5-2.0 mm long × 0.6-1.0 mm wide (width variable within a flower), (0.25-) 0.35-0.4 (-0.5) mm wide at the base; black-mottled on shoulders, the midvein area paler brown; short-ciliate along upper margin and bearded with longer appressed hairs on upper dorsum; membranaceous to chartaceous at anthesis, enlarging slightly and becoming uniformly thickened, and often rigid in fruit, husk-like and non-hygroscopic, enclosing the corolla and fruit and dispersed with it. Petals oblanceolate-spatulate, obtuse to often emarginate or truncate-emarginate, (1.2-) 1.35-1.7 (-1.85) mm long × (.35-) 0.4-0.7 (-0.8) mm wide, ca. 2.2-3.2 (-4.9) times longer than wide, cream to brownish-tinged, with scale-like staminode at base, pilose abaxially near margins of distal half with more or less tuberculate trichomes, also densely tufted subapically within in two patches either side of the apex, which enfold the style branch; like the sepals becoming more or less rigid-thickened in fruit, the staminode also thickening and tightly adherent to both petal and ovary base. Gynoecium with ovary 0.5 mm at anthesis, ca. 0.85 mm in fruit; the style base 0.3-0.5 mm long; the nectaries with stalks 0.25-0.65 mm long, glandular portion 0.2-0.35 mm long, very dark brown or dark reddish, subclavate, with a ring of brown membranous papillae ca. 2-3 rows thick at the apex, the whole structure maintaining its shape after anthesis; style branches 0.6-1.0 (-1.2) mm long, usually ca. 0.2 mm longer than nectaries though often developing unequally, the stigmas simple, dark red-brown, non-involute after anthesis. Seeds subglobose to ellipsoid, mostly 0.6-065 mm long, 0.4-0.55 mm wide, red-brown, reticulate with short weak pseudotrichomes, sometimes glabrate. Staminate flowers: Pedicels 0.15 mm to obsolete. Sepals (1.2-) 1.35-1.75 mm long × 0.5-0.85 mm, usually strongly and unequally fused at base for ¼ -3/4 their length, obovate-navicular above, the apex obtuse-angled to broadly rounded, the tubular base often rigid and obconic at maturity; color and pubescence as in the pistillate flowers. Corolla including anthophore 1.35-1.9 mm; the anthophore 0.65-1.35 mm long, usually ca. 60-70% the corolla length, ca. 0.2-0.35 mm diameter at base, fleshy and columnar at maturity; the corolla tube 0.35-0.75 mm deep, fleshy towards base especially opposite the filaments, the corolla lobes hyaline to brownish, obtuse, 0.15-0.35 mm, not involute after anthesis; intermediate lobes lacking. Stamen filaments with the basal half fleshy, terete and adnate to the corolla, abruptly narrowed and loosely adhering to the lobes above, exsert 0.2-0.5 mm beyond the lobes, the exsert portion dark reddish-brown especially at tip; anthers cream-colored, ca. 0.3-0.35 mm long, usually deciduous after anthesis and not present in fruiting capitula. Nectaries similar to those of pistillate flowers, reaching or slightly surpassing the corolla sinuses.

Etymology.

The epithet is taken from the Greek caryonaute (nom. sing.), the name given to the "nutshell sailors" in Lucian of Samosata’s tale True Stories. It refers to the diaspores enclosed by the thick buoyant perianth.

Phenology.

In Peru and Bolivia, collected in early anthesis in November and December, and with older inflorescences in all months from February to September. The dry season here is May to August but mitigated at higher elevations by cloud cover ( Boyle 2001; Cano et al. 1995). In Colombia and Ecuador, collected on the wet eastern slopes in the slightly drier periods June to September and January; and on the drier western slopes, in the wetter months of March and December ( Rangel-Ch. 2000).

Distribution.

Colombia (Central Cordillera): Cauca, Nariño. Ecuador: Carchi, probably Sucumbíos. Peru: Cuzco, Junín, Pasco. Bolivia: La Paz. In addition, some atypical specimens or hybrids (see below) are known from the Western and Eastern Cordilleras of Colombia, in Antioquia, Meta, and Norte de Santander. (Fig. 6 )

Habitat.

In Peru and Bolivia, this species is restricted to a narrow band of wet paramo-like habitat on the high eastern slope of the Andes, while in Ecuador and Colombia it is found in open wet páramo. It is reported from boggy wet bunchgrass meadows (pajonal) with Calamagrostis Adans. or Festuca procera Kunth, in shallow waterlogged soil of ridgetops and rocky slopes, and in cloud forests and páramo degraded by fire. In Ecuador and Colombia also reported from depressions in Espeletia páramo. Boyle (2001) describes the species as common in the Cordillera Vilcabamba (Peru: Cuzco/ Junín), forming a cushiony matrix together with mat-forming species of Xyris Gronov. and Apiaceae between tussocks of Calamagrostis . Elevation (2940-) 3100-4000 m.

Conservation notes.

This species is known from two disjunct paramo zones, one about 475 km long in the northern Andes and one 950 km long in the central Andes. However, unlike related Paepalanthus pilosus , it is not reported from disturbed areas, and rare outlying populations in Colombia show signs of introgression with Paepalanthus pilosus . In the event of climatic drying or warming this species would be vulnerable, especially in the southern part of its range where suitable habitat is narrowly restricted to the eastern slope.

Misapplied names.

Paepalanthus karstenii f. corei sensu Moldenke (1983) in part, Hensold (2014), non (Moldenke) Moldenke; Paepalanthus muscosus sensu R.C. Foster (1958), Moldenke (1979) in part, Balslev (2001) in part, non Körn.; Paepalanthus pilosus Brako and Hensold (1993) in part, non (Kunth in H.B.K.) Kunth.

Dicussion.

This species is most similar to Paepalanthus pilosus , with a similar cushion-forming habit and similar habitat, and is often confused with that species (or " Paepalanthus karstenii "). In his later annotations, Moldenke frequently identified this species as Paepalanthus karstenii f. corei (Moldenke) Moldenke. It has also frequently been distributed as Paepalanthus muscosus (subsect. Dichocladus ), which also has rounded leaf tips. The report of Paepalanthus muscosus from northern Ecuador by Balslev (2001) is based on vouchers of both Paepalanthus caryonauta and Eriocaulon microcephalum . The species recently cited as Paepalanthus muscosus ( Moscol and Cleef 2009) and Paepalanthus sp. ( Coombes and Ramsay 2001) in vegetation studies of cushion mires in northern Ecuador thus may correspond to Paepalanthus caryonauta in part or full, but confirmation is needed.

Paepalanthus caryonauta is readily distinguished from typical Paepalanthus pilosus and Paepalanthus dendroides by the obtuse leaf tips, and by the sepals uniformly thickened and persistent in fruit, to form an ovoid-ellipsoid diaspore. Even in anthesis, the sepals of Paepalanthus caryonauta are about twice as broad at the base as those of Paepalanthus pilosus and Paepalanthus dendroides . Paepalanthus caryonauta can also be recognized by eye due to subtle differences in aspect and leaf orientation, with the leaves commonly flatter and more ascending, i.e., less conduplicate and recurved than is commonly seen in Paepalanthus pilosus . Boeke, who collected Paepalanthus pilosus and an intermediate form of Paepalanthus caryonauta at the same locality (see below), noted that in Paepalanthus pilosus , the cushions were "easy to separate" and in Paepalanthus aff. caryonauta , "difficult to separate." In the Cordillera Vilcabamba Dudley reported cushions up to 3 feet in diameter (Dudley 11194). However in disturbed roadside páramo at Acjanaco, Young and Cano (1994) comment on the paucity of cushion plants, and do not recognize Paepalanthus caryonauta (" Paepalanthus pilosus ") as a significant cushion plant species. For other differentiating characters, see Table 1 .

Paepalanthus caryonauta has a more uniform morphology throughout its range than its close relatives. However, in Colombia and Ecuador the plants have less thickening in the leaves and flowers, the presence of a short pedicel in the staminate flowers, and peduncles often shorter at flowering time, approaching those of Paepalanthus pilosus in length.

Hybridization.

Paepalanthus caryonauta and Paepalanthus pilosus are mostly allopatric, but in Colombia there are points of contact where intermediates occur. Typical Paepalanthus caryonauta is common in the Nudo de los Pastos and Central Cordillera of Colombia, from which only one historical collection of Paepalanthus pilosus is known, collected ca. 1842. However at the isolated Paramo Frontino in the Western Cordillera, typical Paepalanthus pilosus occurs sympatrically with a morphologically intermediate form of Paepalanthus caryonauta . These two elements were treated as " Paepalanthus karstenii " and " Paepalanthus karstenii var. corei ," respectively, by Rangel-Ch. and Sánchez (2005). In 1976, both elements were collected from Espeletia paramo at Llano Grande, with Paepalanthus aff. caryonauta reported from well-drained hillside (Boeke & McElroy 269), and Paepalanthus pilosus from Sphagnum bog (Boeke & McElroy 265). Paepalanthus aff. caryonauta was re-collected at the same locality in 1986 ( Roldán 402), and Paepalanthus pilosus in 1989 (MacDougal & Roldán 4463, MO). These intermediate plants produce normal seed but have intermediate diaspore morphology (Fig. 5P ). The rounded glossy leaves resemble those of Paepalanthus caryonauta , but those of Boeke & McElroy 269 have long scattered cilia at the upper margin, a trait otherwise only known in Paepalanthus pilosus .

In the eastern Cordillera of Colombia, Paepalanthus pilosus is abundant, while only two specimens suggesting atypical Paepalanthus caryonauta were confirmed, these from opposite ends of the eastern Cordillera, on east-facing slopes. At the south end, an intermediate plant, similar to that of Paramo Frontino, but with flowers mostly abortive, was collected from the eastern slope of Sumapaz National Park (S. Diaz-Piedrahita 2608). This location is just south of the southernmost confirmed Colombian collection of Paepalanthus pilosus . To the north, Cuatrecasas 10302 (F), collected at the "extreme east" of Paramo Santurban (Norte de Santander) may represent Paepalanthus caryonauta or a hybrid intermediate, differing by the light gold bracts. Sympatric taxa in this area include Paepalanthus dendroides , typical Paepalanthus pilosus , and the taxon treated below as Paepalanthus sp. A.

In southern Peru, typical Paepalanthus caryonauta occurs in mixed populations with Paepalanthus dendroides at the entrance to Manú National Park (Abra Acjanaco, Cuzco). Both taxa have been abundantly collected and are readily distinguished in the field (A.Cano, pers. comm.) However, in Pasco (Oxapampa), where both species also occur, a sterile intermediate between the two has been collected. (See discussion of Paepalanthus dendroides .)

Additional specimens examined

(paratypes). COLOMBIA. Cauca: Purace - La Plata, 3200 m, 22 Aug 1957, Barclay 5176 (F, MO); cabeceras Rio Palo , 3700 m, 3 Dec 1944, Cuatrecasas 19099 (F) . Nariño: Mpio. Tangua, Paramo de Las Piedras , 3100-3500 m, 9 Jun 2006, Baca et al. Y-118 (COL [COL000257193]) . Valle del Cauca: Cabeceras Rio Tulua , 3280-3380 m, 24 Mar 1946, Cuatrecasas 20278 (F) . ECUADOR. Carchi: Paramo del Angel , 3700 m, 23 Aug 1957, Barclay 5136 (MO), 28 Sep 1959, Barclay 9374 (MO); Tulcán-Maldonado hwy, km 29, 3845 m, 24 Jan 1977, Boeke 803 (MO); Paramo El Angel, 3500 m, 4 Jan 1973, Humbles 6086 (MO); Rd Tulcán-Maldonado, km 38, 4000 m, 4 Aug 1976, Øllgaard & Balslev 8460 (MO) . PERU. Cuzco: Prov. La Convencion, Cordillera Villcabamba W slopes, 12°36'S, 73°30'W, 3100-3500 m, 14 Jul 1968, Dudley 11060 (F), 28 km NE of Hda. Luisiana and Rio Apurimac, 12°30'S, 73°30"W, 3400-3600 m, 17 Jul 1968, Dudley 11194 (F(2), MO, USM); Huayopata, 7 km from Incatambo, S side of Rio Lucumayo , 3430 m, 4 Aug 1982, Peyton & Peyton 914 (MO) . Cuzco: Prov. Paucartambo, Parque Nac. del Manú, Alturas de Lali , 3750-3850 m, 18 Jul 1990, Cano 3872 (F, USM n.v.), Cano 3873a (USM [photo]); Acjanaco, Cerro Macho Cruz, 3450 m, 30 Aug 1990, Cano 4024 (F, USM n.v.), 3400-3450 m, 2 Mar 1991, Cano 4465 (F p.p., USM [photo] p.p., mixed with Paepalanthus dendroides ); de El Mirador a Cerro Macho Cruz, 3500-3600 m, 21 Jul 1990, León & Young 2245 (F, USM); Cerro Macho Cruz, 3 Sep 1990, León & Young 2431 (USM [photo]); Tres Cruces, 4 Apr 1987, Núñez 7773 (F p.p., USM p.p., mixed with Paepalanthus dendroides ); Paso de Tres Cruces , Cerro de Cusilluyoc , 3800-3900 m, 3 May 1925, Pennell 13864 (F) . Junín / Cuzco: Prov. Satipo / La Convencion, Cordillera Vilcabamba, Rio Ene slope, 11°39'36"S, 73°40'02"W, 3350-3400 m, 8 Jun 1997, Boyle et al. 4219 (F, USM) . Pasco: Prov. Oxapampa, Distr. Huancabamba, Parque Nac. Yanachaga-Chemillen , Abra Yanachaga , 10°22'49"S, 75°27'42"W, 2940 m, 2 Dec 2007, Monteagudo et al. 16143 (F, MO n.v., USM n.v.) . BOLIVIA. La Paz: Franz Tamayo, Parque Nac. Madidi , entre Queara y Mojos, Calistía, 14°41'26"S, 68°59'44"W, 3600 m, 25 Feb 2008, Fuentes et al. 12018 (MO); Bautista Saavedra, Apolobamba, sector Codo, 14°53'06"S, 68°46'35"W, 3274 m, 28 Mar 2009, Fuentes & Huaylla 13574 (F, MO); Cocopunco, 10,000 ft, 24 Mar 1926, G.H. Tate 382 (NY); Tolapampa, 10,000 ft, 11 Sep 1901, R.S. Williams 842 (F, NY) .

Atypical specimens

(not paratypes). Intermediates with Paepalanthus pilosus : COLOMBIA. Antioquia: Paramo de Frontino, near Llano Grande, 3450 m, 27 Oct 1976, Boeke 269 (MO), Urrao, Paramo de Frontino, camino que va del Morro al Quince, 3450 m, 11 Sep 1986, Roldán et al. 402 (MO). Meta: Macizo Sumapaz entre Boqueron del Buque and Laguna del Nevado, 3600 m, 7 Jul 1981, Diaz-Piedrahita 2608 (COL n.v., MO). Norte de Santander: Paramo de Santurban, 3300-3500 m, 27 Jul 1940, Cuatrecasas & Garcia-Barriga 10302 (F, see discussion). Intermediate with Paepalanthus dendroides : PERU. Pasco: Dist. Huancabamba. Sector Santa Barbara, Parque Nacional Yanachaga-Chemillén, 10°12'S, 75°22'W, 3200-3250 m, 27 Jan 2005, Monteagudo et al. 7938 (F, MO n.v.).

Figures

Figure 2. Capitula and leaf tips of Paepalanthus pilosus and relatives A-E Fruiting capitula with diaspores; sepals detaching (A, D) or intact (C, E) A Paepalanthus dendroides B-C Paepalanthus caryonauta D Paepalanthus pilosus var. pilosus E Paepalanthus lodiculoides F-J Paepalanthus pilosus var. pilosus, involucral bract variation. Arrows = tips of the torn peduncle sheath. (A Davidse 28991 B Barclay 5176, Ecuador C Dudley 11060, Peru D Cuatrecasas 25574 E Ollgaard 9717 F Cuatrecasas 25882 G Cuatrecasas 5553 H Ollgaard 9557 I Cano 16840 J Jorgensen 2366.)

Figure 3. Vascular bundle morphology, adaxial side up. A Paepalanthus caryonauta B Paepalanthus pilosus var. pilosus C-E Paepalanthus dendroides F Paepalanthus huancabambensis midvein, with bundle sheath extensions. (A Valenzuela 8117 B Barbour 3427 C Leon 2683 D-E Leon 2243. F: Sagastegui 16799 D-F Mesophyll darkened for contrast.)

Figure 4. Habit of Paepalanthus caryonauta A Boyle 4219 B Fuentes 15374 C-D Valenzuela 8117.

Figure 5. Flowers of Paepalanthus caryonauta (A-O) and suspected hybrid (P). A-G Pistillate flowers in anthesis A Involucral bract subtending flower B Whole flower C Sepal (abaxial) D Petal, adaxial E Petal, abaxial F Flower with one petal and two sepals removed G Gynoecial nectaries H-I Staminate flowers in anthesis H Floral bract I Flower J Staminate flower showing post-anthesis thickening, two anthers fallen K-L Mature diaspores M Diaspore with sepals removed, with thickened petals N-O Seeds P Mature flower of probable hybrid (Roldan 402), with seed. (A-I, N Valenzuela 8117 J-K Dudley 11060 L, O Boyle 4219 M Dudley 11194).

Figure 6. Distribution of Paepalanthus caryonauta and suspected hybrids, Paepalanthus pilosus var. pilosus, Paepalanthus pilosus var. leoniae, and Paepalanthus " Species A. "