Sacoglottis perryi K.Wurdack & C.E.Zartman, 2019

Wurdack, Kenneth J. & Zartman, Charles E., 2019, Insights on the systematics and morphology of Humiriaceae (Malpighiales): androecial and extrafloral nectary variation, two new combinations, and a new Sacoglottis from Guyana, PhytoKeys 124, pp. 87-121 : 98-101

Sacoglottis perryi K.Wurdack & C.E.Zartman sp. nov. Figures 5 , 6 , 7

Diagnosis.

Differs from Sacoglottis guianensis in smaller elliptic leaves, smaller short-pedunculate inflorescences with deciduous bracts, glandular sepals, hirsute ovaries, and subglobose fruits.

Type.

GUYANA. Cuyuni-Mazaruni Region: Below 1st escarpment (of four) of Kamakusa Mt., Powis Creek (2nd) Camp, gallery forest, 5°48'26.7"N, 60°14'6.9"W, 662 m, 20 May 2012 [fl], K. Redden 7264 (holotype: BRG, isotypes: K, NY, US-3694797). Note: type tree of 10 cm dbh was cut down (Fig. 6H ) during sampling and provided a wood sample (K. Wurdack, personal observation).

Description.

Habit usually small tree, 6-8 m, 10-12 cm dbh (to 14 m, 50 cm dbh), trunks lacking buttresses; bark rough, scaly, inner bark coarsely fibrous, dark brown; wood reddish-brown, diffuse porous, growth rings distinct and delimited by a fibrous zone, vessels narrow, mostly solitary, tyloses present, axial parenchyma scanty paratracheal, rays conspicuous (wood described from a 4 cm diam. trunk section); lateral leafy twigs 2-3 mm diam., puberulous, trichomes to 0.1 mm long. Stipules ca. 0.6 × 0.3 (at base) mm, narrowly triangular (rarely with smaller secondary lobes), thickened, glandular, rapidly deciduous. Leaves alternate, distichous on lateral branches, simple; petioles 6-10 (long) × 1 (wide) × 0.8 (high) mm mid-petiole, subterete (dorsiventrally slightly flattened), proximally slightly pulvinate, distally expanded to 2 × wider with narrow wing extending from margins of lamina along shoulders of petiole, sparsely puberulous; blades 4.4-10.8 × 1.7-4.6 cm, length:width ratio 2.19-2.59:1 (mean = 2.37, SD = 0.256, n = 100 from 10 mature leaves × 10 collections), oblong to ovate, base angle obtuse, base obtuse to rounded, apex angle acute, apex shape acuminate with drip tip 0.5-1.5 cm long, tip ending in minute apiculate glandular tooth at distal apex of midvein; subcoriaceous, abaxially sparsely puberulous, adaxially glabrous; basilaminar glands (0-1)2, usually symmetric as pair, along adaxial margin of leaf base, 0.2-0.5 × 0.1-0.2 mm, widely to narrowly elliptic; abaxial laminar glands sparse, up to 4 per side, 0.2-0.7 mm from edge, 0.1 mm wide, nearly circular, slightly sunken; margin shallowly crenate, darkened glandular spots in sinuses, 0.2-0.3 mm diam., when young these spots bearing deciduous glandular setae, 0.3 × 0.1 mm; dark green above and light green below in life; venation pinnate, brochidodromous; secondaries 8-9 pairs, excurrent attachment; intersecondaries frequent. Inflorescences axillary, small (shorter than leaves), <20 flowers, 3-4 orders of branching, peduncle to 1 mm long, rachis 5-10(20) mm long, internal internodes successively shorter in higher order branches, to 2.5 mm long on secondary branches, terminal branches (pedicels) subsessile to 0.5 mm long; bracts 1.8 × 1-1.5 mm, obtuse to rounded, margin entire, sparsely puberulous, rapidly deciduous leaving joint scars. Flowers bisexual, actinomorphic, mature buds 4-4.5 × 1.5-2 mm; calyx cupular, sepals 5, equal, free to base of ovary (when observed from inside), connate at base of receptacle for 1-1.5 mm, imbricate, free portion widely rounded to minutely retuse, 1 × 1.5 mm, sparsely short puberulent (trichomes shorter than elsewhere on plant) inside and out, margin finely ciliate, hyaline, usually with single gland ca. 0.1 mm diam. at minutely retuse apex, in life sepals green and gland red; petals 5, free, 4-4.5 × 1 mm, oblong-lanceolate, tip acute, thick with narrow hyaline entire margin, glabrous, aestivation quincuncial, greenish-white in life and reflexed at anthesis; stamens 10, glabrous, stiffly erect in bud and at anthesis, dimorphic, alternating in 2 lengths; 5 antesepalous longer, filaments 3.5-3.6 mm long; 5 antepetalous shorter, filaments 3 mm long; filaments of both lengths subulate, complanate, basally connate to 1.5 mm and tips free, 0.3-0.5 mm wide at start of free portion × <0.1 mm thick, in life greenish-white; anthers slightly dimorphic and differing in length of connective apex due to tight packing in bud which prevents full development of shorter anthers, antesepalous 0.8-0.9 × 0.5 mm, antepetalous 0.6-0.7 × 0.5 mm, dorsifixed; connective thickened, apical tip acute, base V-shaped and forcing pollen sacs to slightly diverge distally; pollen sacs 2 per anther (disporangiate), ca. 0.3 mm long, in proximal half of anther, stomium narrowly elliptic, covered by valve with a thin dorsal hinge and opening with a ventral lip, yellow-orange in life; ovary 1-1.2 × 1.2-1.3 mm, subglobose, densely hirsute with long trichomes to 0.5 mm; disc 0.5-0.6 mm high, thin, cupular, margin erose with rounded irregular lobes to 0.1 mm high; style 2-2.5 × 0.3 mm, single, columnar, with distinct discontinuity and slightly thinner for distal 1/3, glabrous; stigma minutely 5 lobate-capitate. Infructescence : 1-2 fruits maturing per inflorescence; fruit stalk 5-8 × 1 (diam.) mm, consisting of pedicel and 1-2 inflorescence nodes; petals and anthers caducous, sepals and filaments persistent, filaments forming protective palisade-like sheath around young developing fruit, stigmas and distal thinner part of style senescing rapidly. Fruit drupaceous, 33-35 × 23-30 mm (nearly mature, but ultimate size unknown), length:width ratio 1.07-1.44:1 (mean = 1.23, SD = 0.107, n = 19 from 9 collections, excluding McDowell 2993), sub-globose to ellipsoid, tip short apiculate, glabrescent but sparse trichomes remaining at apex, surface smooth when fresh, when dry sometimes slightly dimpled due to underlying endocarp, exocarp 0.5-1 mm thick; endocarp woody, obscurely bullate on surface due to underlying lacunae, with 3 slight longitudinal furrows, brown, interior with numerous lacunae; lacunae 1.5-5 × 1-4 mm, asymmetric ellipsoidal, greatly varying in size and exact shape within a fruit, in life filled with watery light brown fluid that dries to form thin dark brown, glassy, resinous layer; walls between lacunae <0.05 mm (translucent)-0.5 mm, grading thicker at vertices between multiple lacunae, distinctly thickened around seeds (locule cavity wall) and along the indistinct carpel sutures; locule snug around seed. Seeds 1-3 per fruit, 15 (long) × 5-6 (deep; parallel to embryo) × 4-5 (wide; perpendicular to embryo) mm, oblong, (sub)circular in transverse section, proximal end rounded, distal (hilar) end attenuate; coat thin, papery, brown; endosperm copious, fleshy, oily.

Etymology.

The specific epithet commemorates Claudius Perry (1977-2011; Kelloff et al. 2011: plate 2A), a Wapishana Amerindian originally from Marunawa, who planned to be on the type-collecting trip but tragically perished on 14 Jun 2011 when a portion of his home on the Dadanawa Ranch collapsed during a storm. Although by trade a vaquero (cowboy) in the Rupununi savanna region of southern Guyana, he also served as a parataxonomist and guide on many plant and animal research expeditions (1996-2010) across Guyana. He was especially valued in the many botanical expeditions lead by H. David Clarke ( Kelloff et al. 2011), Karen Redden, and the second author. He accompanied both authors herein, had a keen eye for plant diversity, and was a highly skilled collector, especially of trees that he enjoyed rapidly climbing with spikes. He participated in expeditions that yielded the paratype collections of Forbes 325 and Redden 6582, and personally gathered the latter.

Distribution and ecology.

Sacoglottis perryi is apparently confined to the Pakaraima Mountains of Guyana, and most localities are along mid-elevation (500-800 m) primary and secondary creeks in the headwaters of the Mazaruni River basin. It should be expected in other upland areas of the Mazaruni watershed including in adjacent Venezuela and perhaps Brazil. The tree typically grows in gallery forests at the edge of those waterways, or in forest patches in the white-sand savanna/forest mosaics of the region. Flowering occurs in May–June, with the fruits slowly developing over the course of a year. The timing of fruit ripening, likely in the fall, and features of the ripe fruit are unclear. The Kamakusa collections with the largest fruits on any specimens were hard and green when fresh (Fig. 6I; K . Wurdack, personal observation). In other species (e.g., S. guianensis ; see Holanda 2013) the exocarp turns from green to deep orange, reddish, or brown, and can be fleshy and sweet. The fruits of Sacoglottis spp. are buoyant, leading to long distance transport by water (e.g., as ocean drift); they have also been documented to be dispersed by bats ( Lobova et al. 2009) and monkeys ( van Roosmalen 1985). The accessible position of the fruit of S. perryi on thin, pendulous, distichous-leaved branchlets over small waterway corridors appears advantageous for both bat and water dispersal.

Additional collections examined.

GUYANA. Cuyuni-Mazaruni Region: Imbaimadai, Partang River along riverbank past first rapids NE of base camp, 05°42'10.5"N, 60°16'50.1"W, 873 m, 2 Dec 2002 [fr], Forbes 325 (US); Maipuri Falls, Karowrieng River, 05°41'N, 60°14'W, 570-600 m, 20 Dec 1989 [fr], Gillespie 2810 (US); Imbaimadai Creek, 1 km W of Imbaimadai, 05°42'N, 60°18'W, 500 m, 16 May 1992 [fl, fr], Hoffman 1600 (NY, US); basecamp 8.6 km NE [of] Imbaimadai on Partang River tributary, 0.75 km E, 05°46'N, 60°15'W, 625 m, 20 May 1992 [fl, fr], Hoffman 1745 (MO, NY, US); basecamp 8.6 km NE Imbaimadai on Partang River tributary, 1.25 km E, 05°46'36"N, 60°15'49"W, 600 m, 20 May 1992 [fl], Hoffman 1755 (MO, NY, US); Mt. Aymatoi (sandstone), 05°55'N, 61°W, 1150 m, 16 Oct 1981 [fr], Maas et al. 5753 (MO, US); Imbaimadai Savannas, Upper Mazaruni River, 24 Oct 1951 [fr], Maguire & Fanshawe 32250 (MO, NY); Sagaraimadai Savanna, Upper Mazaruni River, 16 Nov. 1951 [fr], Maguire & Fanshawe 32619 (MO, NY); from Utshe River to Great Falls on Kamarang River, 4-5 km SE of Utshe camp, 05°43'N, 61°07'W, 850-975 m, 26 May 1990 [fl], McDowell 2920 (MO, NY, US); 7 km N of Paruima Village, after descent from south face of Mt. Waleliwatipu, 05°54'N, 61°02'W, 980-1060 m, 30 May 1990 [fl, fr], McDowell 2993 (MO, NY, US-2 sheets); to plateau [at] S end of Haiamatipu, 05°28'N, 60°32'W, 610-914 m, 20 Jun 1991 [fl], McDowell 4734 (NY, US); Imbaimadai Creek, W of Imbaimadai, 05°42'N, 60°18'W, 503 m, 22 Jun 1986 [fr], Pipoly 7990 (MO, NY, US); Vicinity of Chinoweing Village, 5°32'N, 60°07'W, 650-670 m, 21 Feb 1987 [fr], Pipoly 10484 (NY-2 sheets, US); Imbaimadai, Karowrieng River, towards waterfall 2.32 mi E of Base Camp 1, bordering Karowrieng Creek, 5°40'42.4"N, 60°14'30.8"W, 575 m, 22 Jan 2004 [fr], Redden 1489 (US); Mazaruni River, just above ABC Falls, trail/track 2.03 mi SW of Base Camp 6 heading E, 6°4'25.2"N, 60°39'14.3"W, 605 m, 19 Feb 2004 [young fr], Redden 2008 (US); Kako River, top of waterfall, 05°28'50.8"N, 60°50'49.3"W, 687 m, 15 May 2009 [fl, fr], Redden 6582 (US); below 1st escarpment (of four) of Kamakusa Mt., Powis (2nd) Camp and vicinity, along creek bank at camp 5°48'34.6"N, 60°14'21.5"W, 651 m, 21 May 2012 [fl, fr], Tripp 2984 (US); Kako River, gallery forest near rapids, 05°30'27"N, 60°50'30.3"W, 505 m, 10 May 2009 [fl], Wurdack 4911 (US); below 1st escarpment (of four) of Kamakusa Mt., Powis (2nd) Camp and vicinity, along creek bank at camp 5°48'34.6"N, 60°14'21.5"W, 651 m, 13 Jun 2012 [young fr], Wurdack 5898 (US).

Figures

Figure 5. Micromorphology of Sacoglottis perryi. A Marginal glandular seta B basilaminar gland, adaxial C laminar gland near margin, abaxial D sepal tip, inner side with terminal gland E paired glandular stipules and petiole scar F pollen inside sporangium G stigma with ephemeral lobes intact and showing secretion H stigma lobes shredded showing thin walls I gynoecium with diagnostic hirsute ovary J glandular disc with erose margin. Sources: A-C Gillespie 2810 D-J Tripp 2984 (all US).

Figure 6. Macromorphology of Sacoglottis perryi. A Dried fruit with central seed embedded in woody endocarp, longitudinal split along carpel wall (dissected by Cuatrecasas) B dried fruit with 2 central seeds and endocarp lacunae, transverse section C fresh fruit with fleshy yellow-green exocarp and liquid in endocarp lacunae, transverse section D young inflorescence with bracts intact (b) or fallen leaving bract scars (bs) E mature bud with marginal sepal gland (small red dot in center) F partly open flower with intact anthers G post-anthetic flower H freshly cut trunk I type in life just before pressing. Sources: A Gillespie 2810 B Tripp 2984 C, E-I Redden 7264 D Hoffman 1600 (all US).

Figure 7. Illustration of Sacoglottis perryi. A Habit B bud C bud with petals removed D open flower, axial E open flower, lateral F gynoecium G stamen cluster of 2 types, ventral H floral diagram I post-anthetic flower J young fruit K, L fruit M fruit with 2 central seeds and endocarp lacunae, transverse section. Source: A-M from specimens and life photos of Redden 7264 (US).