Phytoneuron

Holst, B.K. 2014. A new species of Ca/yptranthes (Myrtaceae) from Panama. Phytoneuron 2014-77: 1-3. Published 6 August
2014. ISSN 2153 733Xx

A NEW SPECIES OF CALYPTRANTHES (MYRTACEAE) FROM PANAMA

BRuceE K. HOLST
Marie Selby Botanical Gardens
811 South Palm Ave.
Sarasota, Florida 34236
bholst@selby.org

ABSTRACT
A new species of Myrtaceae from Panama, Calyptranthes straminea B. Holst, is described
and illustrated. It is most closely similar to C. contrerasii Lundell from Guatemala, with which it
shares cordate to subcordate leaves and and narrowly winged stems.

Thirty-seven species of Calyptranthes (Myrtaceae) were recently treated in Flora
Mesoamericana (Holst & Kawasaki 2009). While reviewing a collection made in the wet, lowland
forest of Colon Province, Panama, at the mining concession Minera Panama SA (previously Teck
Cominco Petaquilla), it was immediately clear that one specimen represented a new addition to the
Flora and a new species for science.

While most Calyptranthes species are distinguished by their bifurcate vegetative branching,
paired panicles, and circumscissile flowers, the distinction lessens in certain parts of South America
and becomes muddled with its closest relatives, Myrcia and Marlierea. However, following current
generic concepts, the species described here clearly falls into Calyptranthes.

CALYPTRANTHES STRAMINEA B. Holst, sp. nov. TYPE: PANAMA. Colon: Teck Cominco
Petaquilla mining concession, near helipad, 190 m, 8° 50’ 05” N, 80° 39’ 45” W, 21 Jun 2008
(fl), G. McPherson 20568 (holotype: PMA!; isotypes: F, K, MO!, SEL!). Figures 1,2.

Calyptranthes straminea appears related to C. contrerasii Lundell from Guatemala. Both species
have cordate to subcordate leaves and narrowly winged stems. The new species differs by having
numerous flowers per panicle (40-50 vs. to 5), mostly obovate to elliptic leaf blades (vs. ovate to
lanceolate), and abruptly narrowed, shortly acuminate leaf apices (vs. evenly narrowed to an obtuse or
acute apex).

Tree, 9 m tall; mostly glabrous, with few sparse trichomes present at base of flowers; bark
unknown, youngest branchlets narrowly winged, becoming complanate with age. Leaves sessile, the
blades drying grayish to greenish brown adaxially, usually with a rusty color along the adaxial
midvein especially basally, light brown abaxially, obovate to elliptic, 9.5-11 x 45.5 cm, chartaceous
when dry, glabrous, midvein narrowly sulcate adaxially, prominently convex abaxially, secondary
veins 12-18 pairs, slightly ascending, inconspicuous adaxially, visible though not prominent
abaxially, marginal vein 2—2.5(—3.5) mm from the margin and gently arching between the secondary
veins, the outer 1 mm of the margin revolute, apex abruptly narrowed to a 6-10 mm long,
conduplicate-reflexed acumen, base subcordate, somewhat amplexicaul, glands not visible or only
scarcely so adaxially, slightly more visible abaxially with magnification. Inflorescences panicles,
either paired or reduced to one per axil, borne on leafy branches toward branch apices, 5—6 x 2-4 cm,
40—50-flowered, occasionally subtended by a leafy bract to 1 cm long that appears to be caducous at
or before anthesis; peduncles 2-4 cm long, ca. 1.5 mm wide, peduncle and lateral axes stramineous,
heavily gland-dotted, relatively broad compared to flower bud width, glabrous. Flowers short-
pedicellate, the pedicel 0.5 mm long, buds 1.5-2.0 mm long, globose with a blunt apicule;
hypanthium mostly glabrous or with a few sparse, short, broad, and indistinct trichomes basally,
hypanthium collar prolonged 1 mm beyond the summit of the hypanthium with thick, leathery walls,

Holst: New Calyptranthes from Panama 2

calyptra 1.5-2 mm wide, thin, petals absent; stamens ca. 60, filaments 4 mm long, anther thecae
reniform, ca. 0.3 mm long; style gradually narrowing to a punctiform stigma; ovary bilocular, ovules
2 per locule. Fruit and seeds unknown.

Figure 1. Calyptranthes straminea B. Holst. A, habit; B, flower buds; C, detail of flower. Drawn from G.
Me Pherson 20568 (MO).

Holst: New Cafyptranthes from Panama 3

Figure 2. Scan of flowering branch. Inset shows narrow branchlet wings. From G. McPherson 20568 (SEL).

The collection cited below is completely vegetative and perhaps comes from a branch
growing in deep shade. Its leaves are larger than the fertile type collection, to 6 x 18 cm.

Paratype: PANAMA: Colon: Coclé del Norte, Area del helipad C10, 108 m, 8° 48° 29” N.
80° 43° OF" W, 28 Aug 2012 (st), M Laurencio, O. Ortiz, & E. Sanchez 1032 (MO!, PMA).

Etymology. The species epithet straminea refers to the straw-colored inflorescence axes when dried,
which contrast markedly with the dark brownish flower buds

Conservation Status. Calyptranthes straminea is known by one fertile and one sterile collection and.
may be considered data deficient, but it is inherently at risk by being found within a mining
concession.

ACKNOWLEDGMENTS
Thanks to Gordon McPherson for his support in the preparation of the illustration and
comments on the manuscript, to Barbara Alongi for the preparation of the illustration, and to the
herbaria MO and PMA for providing access to the specimens.

LITERATURE CITED
Holst, B.K. and M.L. Kawasaki. 2009. Calyptranthes (Myrtaceae). In: G. Davidse et al. (eds.). Flora
Mesoamericana 4: 69-77.