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Research Article
Strongylodon juangonzalezii, a remarkable new species of Strongylodon (Fabaceae) from Mulanay, Quezon Province, Philippines
expand article infoAnnalee S. Hadsall‡, Michelle D.R. Alejado‡, Ariel R. Larona‡, Ivy Amor F. Lambio‡
‡ University of the Philippines Los Baños, Laguna, Philippines

Corresponding author: Annalee S. Hadsall ( ashadsall@up.edu.ph )

Academic editor: Clifford Morden
© 2016 Annalee S. Hadsall, Michelle D.R. Alejado, Ariel R. Larona, Ivy Amor F. Lambio.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Hadsall AS, Alejado MDR, Larona AR, Lambio IAF (2016) Strongylodon juangonzalezii, a remarkable new species of Strongylodon (Fabaceae) from Mulanay, Quezon Province, Philippines. PhytoKeys 73: 1-12. https://doi.org/10.3897/phytokeys.73.10055
Open Access

Abstract

A new species, Strongylodon juangonzalezii Hadsall, Alejado & Cajano, collected from Buenavista Protected Landscape, Mulanay, Quezon, is hereby described. The new species is remarkable for its plagiotropic dense inflorescence made up of 27–31 flowers per cluster in a lateral branch. Flowers are lilac when young, then gradually turn blue when mature. A comparison of the morphology of S. juangonzalezii and related species of Strongylodon in the Philippines is provided. Detailed illustration based on the holotype and photos from its natural habitat are also included. With this new species, the Philippines now harbors eight endemic species of Strongylodon. A key to distinguish the species is provided.

Keywords

Mulanay, Fabaceae , Quezon, Philippines, Strongylodon

Introduction

Strongylodon (Fabaceae – Papilionoideae – Erythrininae) was described as a genus in 1836 by Julius Rudolph Theodor Vogel. Its distribution includes Madagascar and Reunion to Sri Lanka, India, Australia, and northward to the islands of the Pacific (Polhill 1912, Huang 1991, Tropicos 2016). In the Philippines, Strongylodon is currently distributed in the islands of Luzon (Abra, Cagayan, Bataan, Rizal, Cavite, Laguna, Quezon, Sorsogon, Catanduanes, Mindoro, Aurora Province, Benguet, Ilocos Norte, Isabela, Camarines Sur), Visayas (Biliran, Panay) and Mindanao (Agusan del Norte, Zamboanga, Davao, Lanao, Bukidnon) (Merrill 1923, Pelser et al. 2011).

The genus derived its name from the Greek words “strongylos” meaning ‘round’ and “odontos” means ‘toothlike’, referring to the rounded teeth of the calyx. It is also known to exhibit inflorescences in drooping racemes whose color ranges from purplish blue to bluish green to red or orange red (Huang 1991, Takedaa 2010).

Merrill (1923) enumerated 10 species of Strongylodon in the Philippines, of which 9 are endemic [S. agusanensis Elm., S. caeruleus Merr., S. crassifolius Perk., S. elmeri Merr., S. macrobotrys A. Gray, S. megaphyllus Merr., S. paucinervis Merr., S. pulcher, S. zschokkei Elm.] with one indigenous (S. lucidus (Forst.f.) Seem.). Huang (1991) revised the entire genus resulting in eight species for the Philippines, including a new species, S. loheri and three synonymized species (S. agusanensis a synonym of S. pulcher, S. megaphyllus a synonym of S. macrobotrys, and S. paucinervis a synonym of S. caeruleus). Currently there are seven species, with S. crassifolius reported as insufficiently known (Pelser et al. 2011). The Plant List, an online database (http://www.plantlist.org, 2013), presently recognized 14 species of Strongylodon.

Four sections comprise the genus, namely: Strongylodon, Archboldianus, Macrobotrys, and Craveniae (Huang 1991). All Philippine species of Strongylodon belong to section Macrobotrys characterized by having peltate stipules, brachyblast with more than three-flowers, and purplish blue or bluish-green inflorescences.

In February 2015, a collaborative field study between University of the Philippines Los Baños-Museum of Natural History(UPLB-MNH) and local government unit (LGU) of Mulanay resulted in the collection of 128 plant species belonging to 49 families and 90 genera, with most of the species endemic to the Philippines (Fig. 1). An interesting result of the field study was the discovery of a unique specimen of Strongylodon. Morphological traits were not consistent with other species within the genus. Although similar to S. caeruleus, novel traits include plagiotropic dense inflorescence and young flowers that are lilac-colored then gradually turning blue when mature.

Figure 1. 

Map of Luzon Island showing the geographic location of Mulanay, Quezon Province, Philippines.

Species treatment

Strongylodon juangonzalezii Hadsall, Alejado & Cajano, sp. nov.

urn:lsid:ipni.org:names:77158185-1
Figures 2, 3, 4

Diagnosis

Strongylodon juangonzalezii a habens inflorescentiae racemi spicae densi plagiotropici, lilacinus cum iuvenibus et caerulei cum maturibus, et cum brachyblastae cylindricae et magis quam tres flores in congeners differt.

Strongylodon juangonzalezii differs from other species of Strongylodon in having dense plagiotropic raceme inflorescence with flowers that are lilac when young and turn blue when mature, and with brachyblasts that are cylindrical and more than 3 flowered.

Figure 2. 

Strongylodon juangonzalezii sp. nov. A growth habit, inset shows the distinct middle and lateral stipules B portion of a flowering branch C Detached flower D dissected flower E calyx F androecium and anther G intact pod H pod opened to show the seeds I seeds, front and side view J brachyblast.

Figure 3. 

Voucher specimen of Strongylodon juangonzalezii sp. nov.

Figure 4. 

Strongylodon juangonzalezii sp. nov. A inflorescence B inflorescence showing point of attachment C opened pod to show seeds D young pod E mature seeds from the wild. Photographs by Mary Ann O. Cajano (deceased 6 December 2015) and Michelle DR. Alejado.

Type

PHILIPPINES. Luzon, Island, Quezon Province, Municipality of Mulanay, Barangay Buenavista, Sitio Maglayaw, Buenavista Protected Landscape (BPL), 13°31'20"N, 121°24'15"E, 295 m, 5 February 2015, Cajano & Alejado 7708 (holotype CAHUP 73152!, isotype PNH).

Description

Woody vine reaching the top of the canopy. Mature branches glabrous with lenticels. Leaves 3-foliolate, each 3-nerved, adaxial and abaxial surfaces dark green, margin entire, apex acute, base rounded; lateral leaflets broadly-ovate, oblique, 9 cm long, 6.2 cm wide; terminal leaflet ovate-elliptic, 10.4 cm long, 6.0 cm wide; petiole green, glabrous, base swollen, 12.4–12.6 cm long; rachis green, glabrous, 2.8–2.9 cm long; petiolule green, glabrous, base swollen, 1.2 cm long; stipules three, basifixed, axillary, middle one cylindrical and persistent, lateral ones caducous, leaving conspicuous scars. Inflorescence a dense plagiotropic raceme, up to 12.0 cm long, branches alternating on the main axes; peduncle 2–8 cm, shorter than flowering axis; lateral flowering branches 13.0–27.0 cm long, occurring in pairs, arising from node; pedicel 1.7–1.9 cm long; brachyblasts warty, more than 3-flowered, 5 mm long and 1 mm wide. Flowers 7–9 in a cluster, arranged alternately, 27–31 flowers in a cluster in a lateral branch, with outer flowers opening first; young flowers lilac; calyx lilac, cup-shaped, glabrous, entire; standard petal lanceolate, 2.5–2.6 cm long, 1.3–1.4 cm wide, basal portion ridged, both surfaces of standard petal turns light blue when mature; wings oval 1.2–1.4 cm long, 0.6–0.7 cm wide, slightly auricled at base, upper surface of wings from margin up to 3 mm turns blue when mature, lower surface white; keels lanceolate, 2.8–3.0 cm long, 1.2–1.3 cm wide, both surfaces turn light blue when mature. Ovary pubescent. Pod oblong, globose, unilocular, continuous 6.1–7.5 cm long, 3.9–4.0 cm wide, base rounded, apex aligned with longitudinal axis of fruit, with a green hook, surface glabrous, green with irregular brown marks, dehiscing longitudinally along both sutures. Seeds smooth, symmetrical, 2–3 in a pod, dorsal portion flattened, ventral portion inflated, 2.7–3.1 cm long, 2.1–2.4 cm wide; seed position transverse to fruit length; funiculus whitish, running along ventral side of seed, when mature funiculus is detached leaving a flat scar; hilum linear, around 1.6–1.8 cm of seed, white, with light brown rim; raphe visible; seed coat maroon and shiny when fresh, turning dark brown, papery and wrinkled when mature, not adhering to inner fruit wall.

Table 1.
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Morphological comparison of Strongylodon juangonzalezii sp. nov. with other Philippine species of Strongylodon.

Characters S. juangonzalezii S. caeruleus S. elmeri S. lucidus S. macrobotrys S. pulcher S. zschokkei S. loheri
Terminal leaflet ovate-elliptic ovate elliptic to ovate-elliptic ovate, wide ovate or orbicular elliptic to ovate-elliptic ovate-elliptic, elliptic or oblong elliptic or ovate ovate
Size of terminal leaflet (cm) 10.4 × 6 11–19.5 × 6.5–11 10.5–19 × 3.5–7 0.6–1.3 × 0.55–0.9 12–15.5 × 5.5–7.3 13–22 × 4.2–13 8.5–16 × 3.3–6.7 10–15 × 6–7.5
Lateral leaflet broadly ovate ovate ovate ovate ovate oblong ovate ovate
Size of lateral leaflet (cm) 9 × 6.2 9–16 × 4–8 7.5–16 × 3–7 5–12 × 3–8 9–15 × 3.5–8 11.5–19 × 4.5–10.5 9–13 × 2.8–6 10–13.5 × 4.5–5.5
Flowering habit dense plagiotropic raceme axillary raceme compact, subglobose, terminal raceme pendulous, terminal raceme pendulous, axillary to terminal raceme pendulous, terminal raceme pendulous terminal raceme pendulous raceme
Length of inflorescence axis (cm) 13–27 21–24 18–60 5.5–30 150 3.5–11 19–29 10–19
Brachyblast warty cylindric warty warty warty cylindric warty warty
Number of flowers in a cluster 7–9 7–14 no available data 2–3 5–8 4–10 4–7 5–6
Color of flowers Lilac when young, then blue when mature purplish-blue bluish-green orange-red bluish-green purplish-blue purplish-blue purplish-blue
Pedicel length (cm) 1.7–1.9 1–1.8 3 1.0–2.8 1.8–4 1.5–2.0 1.8–2.3 2.3–2.5
Calyx lilac, cup-shaped purplish, campanulate green, campanulate green, campanulate purplish, campanulate green, campanulate blue, campanulate green, campanulate
Standard petal lanceolate, ovate–lanceolate ovate lanceolate–ovate ovate, reflexed lanceolate ovate, reflexed oblong
Size of standard petal (cm) 2.5–2.6 × 1.3–1.4 2.6–2.8 × 1.2–1.6 2–3 × 1.1–1.6 1.7–3.1 × 1–1.2 3.7–4.8 × 1.7–2.5 2.1–2.5 × 0.9–1 2.9–3 × 1–1.5 3–3.3 × 1.8–1.9
Wing petal shape oval oblong oblong oblong oblong–elliptic oblong oblong oblong
Size of wing petal (mm) 12–14 × 6–7 12–14 × 5–7.5 11–13 × 5.5–7 7–11 × 3.5–6 20–24 × 8–10 8–11 × 3–4.5 10–13 × 5–6 14–17 × 7–9
Size of keel petals (mm) 28–30 × 12–13 27–28 × 4–6 20–28 × 6–8 14–28 × 4–9 45–48 × 11–13 21–23 × 4–5 26–28 × 5–6 29–35 × 7–9.5
Pod shape oblong, globose elliptic, inflated, rugose elliptic, rugose elliptic to elliptic-orbicular elliptic, inflated, rugose elliptic, inflated, rugose elliptic, compressed oblong or elliptic, inflated
Size of pod (cm) 6.1–7.5 × 3.9–4.0 3.5 × 2.1 4–7.5 × 2.2–4 3–8 × 2–4.5 8.5–13 × 6 5.5 × 3.5 9 × 3.5 4.5–6 × 2–2.5
Altitude (m) 295 500–1200 low to medium altitude up to 1600 0–1500 110–1000 80–1200 ca. 1400 1300–1900

Etymology

This new species is named after Dr. Juan Carlos Tecson Gonzalez, current director UPLB-MNH, professor of zoology, one of the Philippines ten outstanding young scientists in 2011, a passionate conservationist and ornithologist.

Distribution

So far only two thriving lianas of this species are known from Buenavista Protected Landscape, Mulanay, Quezon Province where it was collected.

Habitat and ecology

This liana thrives in a disturbed secondary growth forest climbing atop a large tree at an altitude of 295 m. The area is adjacent to an old coconut plantation.

Phenology

Flowering and fruiting from February to mid-March.

Additional specimens examined

Other species of Strongylodon collected in the Philippines were also examined.

Strongylodon caeruleus Merr., Luzon Island, Laguna Province, ML Steiner 1742, March 1959, (PNH);

Strongylodon elmeri Merr., Luzon Island, Laguna Province, ML Steiner s.n., 17 April 1955, (PNH);

Strongylodon macrobotrys A. Gray Exsicc. Gates CA 1442, 1443, 1444; Hernaez CA 12426; Orlido CA 10250; Pancho CA 18190, Reyes CA 2921 (CAHP);

Strongylodon pulcher C.B. Robinson, Mindanao Island, Agusan Province, C. Mahesa & J. Escasina s.n., 23 February 1967, (PNH); Visayas Island, Leyte Province, G.E. Edano 14235, 15 March 1950, (PNH); Mindanao Island, Bukidnon Province, MD Sulit s.n., 10 March 1949, (PNH); Visayas Island, Leyte Province, G. Edano s.n., February 1923, (PNH);

Strongylodon zschokkei Elmer, Luzon Island, Mountain Province, M. Celestino s.n., 13 March 1948, (PNH).

Conservation status

All the materials used in this study were collected from a single population known only from the type locality in a region that is still poorly known botanically. This was the first documentation done inside the protected area. We suggest the preliminary conservation status of this species as Data Deficient (DD; IUCN 2014) and endemic to Luzon Island.

Discussions

Strongylodon juangonzalezii exhibits plagiotropic branches where the dense racemose inflorescences are attached. In the wild, two colors of the flowers are exhibited – lilac color can be observed in young or newly-opened flowers while the mature ones are blue. This is quite remarkable compared with other species of Strongylodon whose flowers retain the same color from bud to fully opened stage. Its pod is oblong and globose while the rest of the species are elliptic. Three shapes of wing petals exist in Strongylodon. It is oval in S. juangonzalezii, oblong on S. caeruleus, S. elmeri, S. lucidus, S. pulcher, S. zschokkei, S. loheri and oblong-elliptic in S. macrobotrys. Calyx shape of S. juangonzalezii is cup-shaped which makes it distinct from the rest. Compared with the other species, S. juangonzalezii occurs at lower elevation.

Key to the species of Strongylodon in the Philippines

1 Inflorescence a raceme, attached on plagiotropic branches; flowers lilac when young, blue when mature; calyx cup-shaped, lilac colored S. juangonzalezii sp. nov.
– Inflorescence a pendulous or drooping raceme; flowers same color all throughout; calyx campanulate, colors various 2
2 Brachyblasts cylindric; flowers purplish blue 3
– Brachyblasts warty; flowers variously colored 4
3 Flowers axillary; calyx purplish S. caeruleus
– Flowers terminal; calyx green S. pulcher
4 Inflorescence axis > 50 cm long; calyx purplish; flowers bluish green, standard petal 3.5-4.5 cm long, wing petal oblong-elliptic S. macrobotrys
– Inflorescence axis < 50 cm long; calyx green to blue; flowers various, standard petal shorter than 3.5 cm, wing petal oblong 5
5 Calyx green 6
– Calyx blue S. zschokkei
6 Inflorescence in compact, subglobose clusters S. elmeri
– Inflorescence in loose, drooping clusters 7
7 Flowers orange-red, 2–3 in a cluster S. lucidus
– Flowers purplish-blue, 5-7 in a cluster S. loheri

Acknowledgement

Permission to collect and transport specimens of Strongylodon juangonzalezii for scientific research was covered by the Wildlife Gratuitous Permit No. R4A-WGP-01-2015-QUE-001 issued by the Department of Environment and Natural Resources (DENR) – Region 4A, Calamba, Laguna. Ms. Mary Ann O. Cajano (deceased 6 December 2015) was part of the team who conducted fieldwork in Mulanay, and she is a co-author of the species S. juangonzalezii. The authors of the paper are grateful to the following staff of the LGU-Mulanay, Quezon Province for their generous support in the field collections: Hon. Joselito Ojeda, Municipal Mayor; Noel M. Eroa, Budget Officer; Engr. Delio H. De Leon, Municipal Engineer; Marcelino Mabini R. Asia – MENRO; Sanny P. Cortez, TSOO/MDRRMO; Linar T. Pereda, Exec. Assistant for Agriculture; Sofronio V. Tesalona, Tourism Assistant; Eymard C. Angulo, IDS Coordinator; Maribeth P. Liwanag, Administrative Aide; Wilfredo B. Mabini and Domingo T. Albaciete, Laborers, Hazel Recalde, Protected Area Superintendent and Pedrito A. Recalde, Field Technician from CENRO-Catanauan. Heartfelt thanks to Dr. Luisito Evangelista of the Philippine National Herbarium (PNH) for allowing access of Strongylodon specimens; Dr. Edwino S. Fernando, MNH Forestry Herbarium (LBC) Curator, for his valuable inputs; Dr. Ireneo L. Lit, Jr. and Mr. Lester Bautista for the Latin translation, Florante A. Cruz for the photoediting, Rafael D. Tandang, for the scientific illustration and Enrico M. Laluan for the digitized map.

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