Myrcia longipaniculata Caliari & V.C. Souza, 2016

Caliari, Claudia Pigatti, Souza, Vinicius Castro & Mazine, Fiorella F., 2016, Two new species of Myrcia (Myrtaceae) from Brazilian Atlantic Forest, Phytotaxa 267 (3), pp. 201-210 : 205-209

2. Myrcia longipaniculata Caliari & V.C. Souza , sp.nov.

Type:— BRAZIL. Divisa RJ–SP, Km 0, “picada em beira da estrada” , 22 November 1990, M. Nadruz 651 (holotype RB!) . Figures 3 , 4 , 5B , 6B

This species is related to Myrcia spectabilis , from which it is distinguished by its dense reddish to ferrugineous indumentum combined with larger inflorescence (29 versus 3.5–21.5 cm long.).

Tree, 6 m tall; twigs flat to sulcate, with a pilose to lanuginose, farinaceous indumentum, reddish to ferrugineous, persistent. Leaf blade lanceolate, chartaceous, margins flat to slightly curved; discolored, dark brown adaxially, light green abaxially; blades 35 × 12.2 cm, glabrescent with the midrib sparsely pilose adaxially and slightly lanuginose abaxially; gland dots flat to slightly impressed and dark adaxially, indistinct abaxially, apex acute to slightly acuminate, base rounded to slightly cordate, midrib sulcate adaxially, salient abaxially, lateral veins ca. 27 pairs, slightly salient to impressed adaxially, salient abaxially; marginal veins 2, respectively up to 6 mm and 0.1 mm from margin, petioles 5 mm long, canaliculate; interpetiolar scar linear. Inflorescence in terminal panicles, erect, ca. 29 cm long, pilose or lanuginose, farinaceous under the trichomes, ferruginous to reddish; bracts not seen. Flower buds, ca. 7 mm long, uniformly lanuginose; bracteoles not seen; calyx with 5 lobes, these depressed ovate, 2 mm long, rounded; anthers elliptic with 0.6–0.7 × 0.3–0.4 mm; hypanthium 2.2–2.5 mm, smooth; ovary bilocular, with two ovules per locule. Fruits not seen.

Distribution and habitat:— Boundary between São Paulo and Rio de Janeiro states, in the Atlantic rainforest.

Phenology:— Flower buds and flowers in November.

Etymology:— The epithet refers to the length of inflorescence.

Conservation status:— This species occurs in the border of Paraty and Ubatuba, two contiguous and very well collected municipalities, which sum 1,649 km ² ( IBGE 2015). Specieslink ( CRIA 2016), a site that exhibits collections from all major Brazilian herbaria, registered 35,600 specimens within its limits, resulting in an average of 21 collections/km², a high sampling effort when compared with the Brazilian average of 0.59 collections/km² calculated by Sobral & Stehmann (2009). In spite of this, and the present efforts to recollect this species, Myrcia longipaniculata was collected only once, which is a good indication of its probable rarity. Applying IUCN evaluation criteria to M. longipaniculata , it presents an area of occupation smaller than 10 km ² (B2) in the Atlantic Forest, where many species are seriously threatened by anthropogenic pressure ( Myers et al. 2000, Orme et al. 2005). Also it is known from a single locality (B2.a), with a very small, restricted population (D), as inferred by the number of sampling in a well collected locality. We therefore evaluate this species as CR (critically endangered) IUCN (2001).

Affinities and discussion:— This species has vegetative morphology similar to Myrcia spectabilis De Candolle (1828: 248). These two species are distinguished by the characters in the following key:

1. Twigs striated; twigs and inflorescence indumentum with setose trichomes or lanate to dense-lanate, brown to yellow, tending to golden, dark brown or cream (Figure 5A); leaves puberulous abaxially; inflorescence with maximum 21.5 cm long (Figure 6A) .. ................................................................................................................................................................................ Myrcia spectabilis

– Twigs not striated; twigs and inflorescence with lanuginose indumentum, reddish to ferrugineous ( Figure 5B ); leaves sparsely pilose on midrib and the indumentum more or less lanuginose abaxially; inflorescence with about 29 cm long ( Figure 6B ) ........... ........................................................................................................................................................................ Myrcia longipaniculata

Figures

FIGURE 3. Myrcia longipaniculata. A. Leaf blade adaxial surface; B. interpetiolar scar and indumentum pilose to lanuginose; C. flower bud. Illustration by Samira Rolim from the Holotype.

FIGURE 4. Myrcia longipaniculata. Image of the Holotype at RB. (M. Nadruz et al. 651).

FIGURE 5. Twigs. A. Myrcia spectabilis (N.M. Ivanauskas et al. 5051—ESA). B. Myrcia longipaniculata (M. Nadruz et al. 651—RB).

FIGURE 6. Inflorescences. A. Myrcia spectabilis (F.F. Mazine et al. 767—ESA). B. Myrcia longipaniculata (M. Nadruz et al. 651— RB).