FWS Focus

Overview

Characteristics
Overview

Gonocalyx concolor is a Puerto Rican endemic plant species with no common name that has been found growing only within the Carite Commonwealth. Currently, this species is represented by 78 individuals that are distributed in two populations: 74 individuals at Cerro La Santa and four individuals at Charco Azul. Gonocalyx concolor is threatened by habitat destruction, modification and fragmentation from construction and expansion of telecommunication towers and associated facilities, as well as vegetation clearance and road improvements at Cerro La Santa. Compounding these threats are the limited distribution and highly specialized ecological requirements of this species. Collectively, these species characteristics exacerbate the potential threats posed by other factors like landslides, human induced fires, competition and environmental effects resulting from climate change climate change
Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.

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Scientific Name

Gonocalyx concolor
Common Name
island brittleleaf
No common name
FWS Category
Flowering Plants
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Behavior

Characteristics
Behavior
Characteristic category

Habitat

Characteristics
Habitat

Gonocalyx concolor has been found only in the elfin forest in Cerro La Santa and in the ausubo (Manilkara bidentata) forest types around Charco Azul, both located in the Carite Commonwealth Forest. The elfin and ausubo forests fall within the subtropical lower montane very wet forest life zone; thus, both forest types have similar climate conditions.

This elfin forest, also referred to as dwarf or cloud forest, is found on exposed peaks and ridges, above 2,900 feet (880 meters) in elevation, occupying approximately 24.9 acres (10.1 hectares) of the total area of Carite Commonwealth Forest. This forest type is characterized by gnarled trees less than 22 feet (7 meters) tall. This forest is frequently covered in clouds, thus, the vegetation is commonly saturated with moisture. The plant association in this area is generally comprised of a few species of native trees, native ferns and a dense coverage of epiphytes, including bromeliads and mosses. Here, Gonocalyx concolor has been found growing over the Caimitillo tree (Chrysophyllum oliviforme), the invasive plant lengua de vaca (Aegiphila martinicensis) and over dead trees, but not on the forest floor.

The ausubo forest is only found along the Río Grande de Patillas River Basin and along intermittent streams in the area between 2,034 feet (620 meters) and 2,329.4 feet (720 meters) of elevation. This forest type is represented by the ausubo tree (Manilkara bidentata) and occupies approximately 179.2 acres (72.5 hectares) of the Carite Commonwealth Forest. Additionally, it is characterized by evergreen vegetation, high species richness, rapid growth rate of successional trees, epiphytic ferns, bromeliads and orchids.

Although the specific habitat requirement of G. concolor has not been studied, it seems that these forest types provide the suitable habitat conditions, including substrate, moisture and temperature, for the species persistence. G. concolor is found growing on the canopy of the tallest tree areas, on tree trunks, or epiphytic, clambering - meaning that the plant uses other vegetation as support. This species is also found lying on the litter in the forest floor.

Forest

A dense growth of trees and underbrush covering a large tract.

Mountain

A landmass that projects conspicuously above its surroundings and is higher than a hill.

Characteristic category

Food

Characteristics
Food
Characteristic category

Physical Characteristics

Characteristics
Size & Shape

Gonocalyx concolor is a small evergreen shrub, which may reach 15 feet (4.7 meters) in length. The leaves are simple, alternate, entire and coriaceous, or leathery. The leaf blade is ovate, broadly elliptic or nearly orbicular. The leaf base is apiculate, meaning that it ends in a short sharp point, and obtuse to acute at the apex. It is rounded at the base and the leaf’s upper surface is glabrous, meaning smooth or hairless, above, with scattered large trichomes, which are papilliform hairs, beneath. Young leaves and branches are brilliantly rose-colored, but become green with age. The stems are highly branched, slender, cylindrical and dark brown in color. The flowers are bright red that are borne solitary on short shoots, are semipendent, meaning hanging or suspended. The flower has five merous, or floral part in multiples of five in each whorl, regular, and uniformly vivid red. The corolla consists of the separate or fused petals and constitutes the inner whorl of the perianth, the tube is carnose, or of a fleshy consistence, and campanulate, meaning that it is shaped like a bell. Fruits of G. concolor are bright red berries with many seeds inside.

Weight
Color & Pattern
Sound
Characteristic category

Life Cycle

Characteristics
Life Cycle

Gonocalyx concolor has been observed flowering and fruiting all year around, but with more abundant flowering during the months of June, July and August. To date, no seedlings have been documented in the wild. The low number of individuals per population may suggest that G. concolor has highly specialized ecological requirements for growing and that production of viable seeds rarely occurs. Currently, no information about reproductive capacity, dispersion or habitat requirements is available for G. concolor. Hummingbird has been identified as possible pollinator of the flowers of G. concolor.

Life Span
Reproduction
Life Cycle

N/A

Characteristic category

Similar Species

Characteristics
Similar Species

Although Gonocalyx concolor is similar to G. portoricensis, differences in flower morphology indicate that they are well-differentiated species. The flower of G. portoricensis is pendent with light green calyx and the corolla tube is whitish to pinkish; it is an insect-pollinated flower. 

Geography

Characteristics
Range

As endemic to Puerto Rico, G. concolor in only known from the Carite Commonwealth Forest. The Carite Commonwealth Forest lies within the Sierra de Cayey, a mountain range located in the east-central region of Puerto Rico, with elevations ranging from 820 to 2,962 feet (250 to 903 meters). This forest covers an area of approximately 6,600 acres (2,671 hectares), extending into the municipalities of Caguas, Cayey, Guayama, San Lorenzo and Patillas.

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