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Plant Ecology and Evolution 152 (3): 546–553, 2019
https://doi.org/10.5091/plecevo.2019.1595
Justicia gigantophylla (Acanthaceae), an endangered litter-gathering
species from southern Cameroon
Harry J. Smith1,*, Con Moran2, Olivier Lachenaud3,4 & Iain Darbyshire1
1Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AE, UK
2School of Medicine, College of Medicine and Health, University College Cork, Ireland
3Botanic Garden Meise, Nieuwelaan 38, 1860 Meise, Belgium
4Université Libre de Bruxelles, Boulevard du Triomphe, 1050 Brussels, Belgium
*Corresponding author: harry.smith@kew.org
SHORT COMMUNICATION
Background and aims – The taxonomic status of Duvernoia gigantophylla Lindau from southern
Cameroon is considered in relation to the wider Justicia extensa-laxa complex of tropical Africa. Its
unusual litter-gathering habit (currently unique in Acanthaceae) is also discussed.
Methods – This study was based on normal practices of herbarium taxonomy and morphological analysis.
All relevant protocols were followed in the production of the conservation assessment and selection of the
lectotype.
Key results – A new combination Justicia gigantophylla (Lindau) H.J.Sm. & C.Moran is proposed for this
narrowly endemic and endangered species, which is re-instated, with a new description and conservation
assessment. A basic key to the wider J. extensa-laxa complex is presented. Justicia gigantophylla is assessed
as Endangered (EN B1ab(iii)+2ab(iii)) according to the 2012 criteria of IUCN and a new lectotype is also
designated.
Keywords – Cameroon; Acanthaceae; Justicia; litter-gathering; species complex; conservation.
© 2019 The Authors. This article is published and distributed in Open Access under the terms of the Creative Commons Attribution
License (CC BY 4.0), which permits use, distribution, and reproduction in any medium, provided the original work (author and source)
is properly cited.
Plant Ecology and Evolution is published by Meise Botanic Garden and Royal Botanical Society of Belgium
ISSN: 2032-3913 (print) – 2032-3921 (online)
INTRODUCTION
With 500 species (almost certainly an underestimate), Justi-
cia L. s. lat. is the most species-rich genus within the Acan-
thaceae family (Vollesen in Darbyshire et al. 2010). Rec-
ognized as one of world’s ‘megagenera’ (Frodin 2004), the
sheer scale and morphological diversity of Justicia continues
to pose signicant challenges to taxonomists, with compre-
hensive treatments being unavoidably complex and dicult
to produce. Over the last two centuries, hundreds of species
and several whole genera have been moved in and out of
Justicia; most accounts treating only particular geograph-
ic regions and taxonomists disagreeing on whether to take
a broad or narrow approach to the genus overall (Graham
1988). The taxonomic intricacy of Justicia extends to the
Justicieae tribe, which has been described as ‘the most taxo-
nomically dicult group in Acanthaceae’ (Kiel et al. 2017)
and which continues to resist clarity even with contemporary
molecular methods.
This study focuses on a small group of African species
of Justicia, the J. extensa T.Anderson-J. laxa T.Anderson
complex (Anderson 1863). The species within this complex
are rainforest understorey perennial herbs and shrubs oc-
curring across the “Guineo-Congolian” forest belt (White
1983), extending from Guinea in the west to Kenya in the
east and to northern Angola in the south. The complex is cur-
rently divided into two widespread species: J. extensa and J.
laxa (Heine 1963, 1966; Vollesen in Darbyshire et al. 2010).
Each of these species has several nomenclatural synonyms,
a result of formerly segregated taxa having been subsumed
547
Smith et al., Justicia gigantophylla (Acanthaceae)
within the two more broadly circumscribed species. Justicia
laxa is listed as of Least Concern (LC) on the IUCN Red List
of Threatened Species, and although not on the formal Red
List, J. extensa has also been assessed as of Least Concern
following the IUCN (2012) criteria (Cheek et al. 2004).
However, preliminary studies of the large volume of her-
barium material available for this group (c. 900 specimens at
K, P, BR and WAG alone) have revealed a large range of mor-
phological variation within each species, with at least some
of this variation separable into discrete taxa. Some of these
entities also appear to have a restricted range and so may be
of high conservation signicance yet, as with many cryptic
species, they are currently hidden within widespread species
of low perceived conservation value. Besides Champluvier’s
unpublished eorts to unravel the complex within Central Af-
rica (annotated specimens seen at BR and K), the exact rela-
tionships between and within these species are yet to be fully
resolved. This study aims to begin that process by providing a
basic key to the J. extensa-laxa complex and by resurrecting
Duvernoia gigantophylla Lindau with a new combination in
Justicia; a particularly distinct and highly threatened member
of the group hitherto obscured by an incomplete taxonomy.
MATERIAL AND METHODS
This study is based on detailed morphological studies of her-
barium material, using specimens held at BR, BRLU, K, P,
and WAG (herbarium abbreviations following Thiers con-
tinuously updated) as well as digitised type material seen
on JSTOR. Data on distribution, ecology and nomenclature
were taken from specimen labels and from eld observa-
tions by Martin Cheek, one of the most recent collectors of
the species. The geographical coordinates for each specimen
were databased and error-corrected where necessary. Speci-
men data was imported into SimpleMappr (Shorthouse 2010)
and used to produce distribution maps. The online tool Geo-
CAT ( http://geocat.kew.org/, Bachman et al. 2011) was used
to calculate the area of occupancy (AOO) and extent of oc-
currence (EOO). Both gures were then used alongside the
IUCN red list categories (IUCN 2012) to produce a full con-
servation assessment for J. gigantophylla. Due to the limited
material available, oral measurements were based on a to-
tal of three owers (taken from Cheek 17553 and Letouzey
4095). These were two whole, dried owers and one dissect-
ed ower, which was rst rehydrated using Aerosol OT 5%
solution. Nomenclature adheres to the protocols of Turland
et al. (2018) and binomial authorities to IPNI (continuously
updated). All cited specimens have been seen by the authors.
RESULTS
Preliminary key to the Justicia extensa-laxa complex
Based on the preliminary results of this study, J. laxa is pro-
visionally separated into three taxa of which J. gigantophylla
is the most distinctive and discrete. J. gigantophylla is sep-
arated ahead of a full revision due to its highly threatened
position and consequent need for formal recognition. The
closely related J. extensa complex will likely also warrant
subdivision following further investigation.
Justicia gigantophylla (Lindau) H.J.Sm. & C.Moran, comb.
nov.
Duvernoia gigantophylla Lindau, Botanische Jahrbücher fur
Systematik, Panzengeschichte und Panzengeographie. 49:
406 (Lindau 1913). – Type: Cameroon, South Dist., bei Fen-
da, 58 km E Kribi, 1910–1911, Mildbraed 5841 (holotype
B†; hololectotype: HBG, barcode HBG502243, designated
here; isolectotypes: P, barcode P00434952, HBG, barcode
HBG502552).
Figs 1– 4
Erect, single-stemmed herbs of 0.5–2 m; monopodial
growth characteristic of litter-gathering habit; stem me-
dium to dark green with swollen nodes, sparsely pubescent
towards apex, soon glabrescent, the apex with short inter-
nodes and leaves forming a pseudo-rosette. Leaves slanting
upwards, arranged forming a funnel (Cheek pers. obs.), ob-
long-oblanceolate, thinly leathery (Bos 3667), medium green
above, pale green beneath; 15–40 cm long, 5–15 cm wide,
base amplexicaul and tightly clasped around stem, basal
margins raised, forming a saucer, short internodes towards
stem apices of opposite-decussate pairs forming a pseudo-
rosette, occasionally base subcordate with very short petiole
± 1 cm, distal quarter of blade corrugated along the midrib
(g. 1B) margins entire, apex cuspidate, ± 13–20 pairs of lat-
eral veins, glabrous on both surfaces except for short, sparse
hairs on abaxial veins; tertiary veins laxly reticulate and con-
spicuous on the lower surface; cystoliths inconspicuous even
in dried material. Inorescence a terminal, paniculate thyrse
(5–)10–25 cm long, 3.5–15 cm wide, comprising a series
Preliminary key to the Justicia extensa-laxa complex
1. Ovary and capsule pubescent .......................................................................................... J. extensa agg.
1’. Ovary and capsule glabrous .................................................................................................................. 2
2. Leaves (sub)sessile, blade oblanceolate, 20–40 cm long, with 15–20 pairs of lateral veins; calyx lobes
broadly ovate, 3–6 mm wide with adjacent lobes overlapping with margins adpressed, forming a star
shape to the calyx in cross section ...............................................................................J. gigantophylla
2’. Leaves petiolate, petioles 2–10 cm long, blade elliptic or ovate, 10–25 cm long, with up to 12 pairs of
lateral veins; calyx lobes lanceolate or linear-lanceolate, up to 2.5 mm wide, not or barely overlapping
and not forming a star shape in cross section....................................................................................... 3
3. Panicles oblong and contracted, 2–5 cm wide, bracts linear-lanceolate, < 1 cm long . “J. pyramidata”
3’. Panicles more lax, 9–15 cm wide, bracts foliaceous, ovate, 2–4 cm long ................................... J. laxa
548
Pl. Ecol. Evol. 152 (3), 2019
Figure 1 – Justicia gigantophylla. A. Upper part of plant with inorescence (lacking terminal portion); articially enlarged to avoid being
obscured by right-side leaf. B. View of leaves (from photograph) in live plant from above to show puckering of young leaf surfaces and
undulate leaf margins. C. Indumentum on axial midrib. D. Indumentum on pedicels/peduncles. E. Flower, face view, and neighbouring buds
on lateral branch of inorescence. F. Anterior face of corolla tube (with lobes raised) to show deep median and shallower lateral inations.
G. Corolla, cut and opened – the deep median ination (on the right) is lined with inside as well as at its margins. H. Disc, ovary, style and
stigma. I. Calyx, cut and opened, inner surface. J. Fruit, dehisced, with one immature seed in situ. K. Mature seed – pattern indicated is
present over both surfaces. A, C–I from Cheek 17553 (K). B from eld photograph by M. Cheek (see g. 2). J and K from Letouzey 4095 (K).
Scale bars: single bar = 1 mm; graduated single bar = 2 mm and 5 mm; double bar = 1 cm; graduated double bar = 5 cm. Drawn by Andrew
Brown.
549
Smith et al., Justicia gigantophylla (Acanthaceae)
of open to rather dense dichasial cymes; inorescence axes
shortly antrorse-pubescent; bracts along main inorescence
axis linear-lanceolate, 0.3–1 cm long, 0.1–0.3 cm wide (at
midpoint of inorescence), lowermost bracts often larger and
more leaf-like, antrorse-pubescent, bracteoles of same shape
as bracts but smaller; cymes 1.7–6 cm long, pedicels 0.1–0.5
cm long. Calyx pale green with wine-red margin, deeply di-
vided into ve subequal suborbicular to broadly ovate lobes,
0.3–0.6 cm long, 0.3–0.6 cm wide, obtuse to faintly acute
at apex, glabrous or with median vein sparsely antrose-pu-
bescent, strongly reduplicate with adjacent lobes overlapping
and margins adpressed, forming a star shape to the calyx in
cross section. Corolla 13–14 mm long (base of tube to tip
of upper lip), minutely pubescent to glabrous externally and
with short hairs on the margin of upper lip, conspicuously
hairy within corolla tube; rugula (stylar furrow) present on
dorsal side of tube and extending onto upper lip, with fringe
of hairs in lower portion; tube 7–8 mm long, c. 4.5 mm
broad, slightly ventricose above basal constricted portion of
± 1 mm; upper lip held erect, 5–7 mm long, c. 3.5 mm broad,
somewhat hooded in situ, broadly ovate when attened, apex
emarginate, lower lip deexed, 5–7 mm long, c. 6 mm broad,
conspicuously 3-lobed for ± 3 mm, palate without conspicu-
ous “herring-bone” venation. Stamens exserted, laments ±
Figure 2 – Field photograph (by M. Cheek) of J. gigantophylla in
lowland evergreen forest (Cheek 17553).
Figure 3 – SEM images of J. gigantophylla pollen. A. Apertural
view. B. Polar view. C. Detail of interapertural exine. Material used:
Cheek 17553.
3.5 mm long inserted ± 1.7 mm below corolla mouth, thecae
oset by ± 0.5 mm, upper theca ± 1.5 mm long, pubescent on
external side, with minute, rounded appendage, lower theca
± 1.5 mm long, glabrous, with ± 0.5 mm long ivory to cream-
yellow appendage, blunt at the tip, stamens diverging at ma-
turity. Ovary glabrous, c. 1 mm long, style 10.5–11.5 mm
long, dark reddish-brown, strigose to glabrous, stigma short,
550
Pl. Ecol. Evol. 152 (3), 2019
lighter in colour (creamy yellow), minutely 2-lobed. Capsule
4-seeded, ± 3 cm long, glabrous, upper fertile portion ± 1.5
cm long, lower sterile stipe ± 1.5 cm. Seeds 0.3–0.5 cm in
diameter, golden-brown, discoid, in face-view sub-orbicular,
rugulose. – Figs 1 & 2.
Pollen prolate, 4-colporate, 8-pseudocolpate; P = 39–46
µm, E = 25–34 µm, P/E = 1.15–1.5; colpi and pseudocol-
pi approximately equal in length or pseudocolpi somewhat
longer, extending to near the poles but not meeting; pori
prominent, ± 6.5 µm wide; colpi and pseudocolpi microver-
rucate, interapertural and polar exine reticulate with micro-
verrucate lumina. – Fig. 3.
Distribution – Africa: Cameroon. Known only from a small
area of South Cameroon Region around the resort and port
town of Kribi and inland to Bipinde. – Fig. 4.
Other specimens examined – CAMEROON. Bipinde,
1898, Zenker 1840 (K, P); between Fenda, (60 km ESE of
Kribi) and River Kienke, 22 Jan. 1962, Letouzey 4095 (K,
P, YA); Njabilobe (54 km ESE Kribi); 2 km W village, 12
Mar. 1963, J. & A. Raynal 10386 (P, YA); Ebemwok (55
km W Ebolowa), SE of the village, 13 Mar. 1963, J. & A.
Raynal 10448 (P, YA); 15km SSE of Zingui (50 km to the
SE of Kribi), 14 Mar. 1968, Letouzey 9027 (K, P, YA); about
16 km. from Kribi, Lolodorf road, 18 Jan. 1969, Bos 3667
Figure 4 – Distribution maps of J. gigantophylla (top: long range; bottom: close range).
551
Smith et al., Justicia gigantophylla (Acanthaceae)
(P, WAG); about 15 km SE of Kribi, Kienke For. Res, at Bi-
dou II, 30 Jun. 1969, Bos 4949 (P, WAG); 38 km by road
north of Akom II which lies on the Kribi-Ebolowa Rd. 22
Mar. 2014, Cheek 17553 (K, YA,); Massif de Ngovayang,
village de Ngovayang, 9 Jun. 2015, Droissart et al. 1906
(BRLU); Ngovayang Massif, village of Atog Boga, 1 Sep.
2015, Droissart et al. 2089 (BRLU); Massif de Ngovayang,
au-dessus du village d’Atog-boga, 2 Sep. 2015, Texier et
al. 9 (BRLU); same locality, 3 Sep. 2015, Texier et al. 14
(BRLU).
Habitat, ecology and phenology – Litter-gathering under-
story herb found mostly at roadsides and within forest clear-
ings, sometimes near streams. Atlantic Equatorial Coastal
Forests (White 1983). Mostly at elevations between c.300–
900 m. Flowering occurs during rainy season between May/
June and September/October.
Conservation assessment – A full IUCN conservation as-
sessment is in press (Smith in press), which gives this spe-
cies the current status of Endangered - EN B1ab(iii)+2ab(iii).
This is based on the limited EOO of < 5,000 km2 (3,427 km2)
and AOO of < 500 km2 (44 km2), the small and fragmented
number of locations, and the imminent/currents threats of
open-cast mining, logging and population growth in the im-
mediate vicinity of the known locations.
Uses – Thus far, there are no described uses for this taxon,
though its close relatives J. laxa and J. extensa are known for
their economic and medicinal value. Both species are used as
sh poisons throughout their native range in West Africa, and
J. extensa is reportedly used as a treatment for a wide range
of ailments; from headaches to epilepsy (Burkill 1985).
Notes – Justicia gigantophylla is based on Lindau’s (1913)
Duvernoia gigantophylla (see Discussion). It is clearly re-
lated to J. laxa T.Anderson, which it closely resembles in
characters of the inorescence, corolla, and anthers, but
can be immediately separated by its oblanceolate, sessile
or very shortly petiolate leaves that clasp the stem to form
litter-gathering rosettes. The leaves are also larger than in J.
laxa and usually bear more lateral veins, and the calyx lobes
are much wider, with the margins adpressed to one another,
forming a star shape in cross-section. J. laxa has more el-
liptic, regularly spaced leaves with a longer petiole, and nar-
rowly lanceolate calyx lobes that are held at.
Due to limited suitable material available for study, the
pollen description for J. gigantophylla presented here is
based on a single accession, Cheek 12553. The 4-colporate,
8-pseudocolpate reticulate pollen of that specimen is very
similar to that reported for J. extensa, except that it is 4-aper-
turate whereas J. extensa is 3-aperturate (Graham 1988; Kiel
et al. 2017). 3-colporate, 6-pseudocolpate pollen (as in J. ex-
tensa) is hypothesized to be synapomorphic for Justicieae as
a whole (Kiel et al. 2017). However, aperture number is vari-
able within the justicioids and it is clear that aperture num-
ber has evolved homoplastically across this clade (Kiel et al.
2017). Whilst pollen grains with 2 or 3 apertures are the most
commonly encountered, some New World justicioids have
up to 6 apertures, and 4-aperturate grains have been reported
in several justicioid taxa, such as Anisotes guineensis Lindau
(Baden 1981). Given this variation and homoplasy, pollen
characters appear to be of limited taxonomic within the justi-
cioids at the generic level. However, a more exhaustive study
of the pollen morphology of the J. laxa-J. extensa complex
may, nevertheless, prove to be useful in species delimitation,
particularly if aperture number proves to be consistent within
species.
The lectotype selected here is one of two sheets of Mild-
braed 5841 held at HBG; the voucher in far superior condi-
tion is the one selected here. An image of the specimen is
accessible at http://www.herbariumhamburgense.de/her-
barsheets/disk_batch01/medium/HBG-502243.jpg
DISCUSSION
Taxonomic history and position of the species
Justicia gigantophylla was rst described in 1913 by Gustav
Lindau under the name Duvernoia gigantophylla and noted
by the author for its resemblance to J. extensa, which Lin-
dau also transferred to Duvernoia Nees. Duvernoia was rst
described from South Africa (D. adhatodoides E.Mey. ex
Nees) but subsequently much expanded by Lindau. Despite
Lindau’s condence in Duvernoia, its validity as a genus was
challenged by Burkill & Clarke (1900) in the Flora of Tropi-
cal Africa (FTA) who noted that Lindau appeared to have
circumscribed Duvernoia based on one character; that of the
lack of tubercles on the smooth bands of the pollen. Burkill
& Clarke (1900) wrote “we nd the group contrary to nature
itself; it appears not a genus, but a handful of species taken at
random from every part of the genus Justicia (in a very wide
sense)”. Consequently, Burkill & Clarke moved all known
species of Duvernoia into Justicia. Most recent treatments
have followed this decision (e.g. Lebrun & Stork 1997; Scot-
land & Vollesen 2000; Vollesen in Darbyshire et al. 2010,
2015; Manning & Goldblatt 2014).
However, Lindau continued to uphold Duvernoia post-
FTA and although Duvernoia gigantophylla was rst collect-
ed in 1898 it was not described until 1911, nearly a decade
after Clarke’s FTA treatment. Duvernoia gigantophylla has
not been covered in any subsequent oristic treatment. It is
not mentioned in the Flora of West Tropical Africa (Heine
1963), which only extends as far east as the former ‘British
Cameroons’ (modern-day Northwest and Southwest Cam-
eroon Regions), i.e. outside the range of D. gigantophylla,
which is only known from the South Cameroon Region.
Similarly, Heine (1966) in Flore du Gabon did not discuss D.
gigantophylla in relation to J. extensa or J. laxa. The name
is entirely omitted from modern checklists of the vascular
plants of Cameroon (Onana 2011, 2013) or of continental
Africa (Lebrun & Stork 1997; Klopper et al. 2006; African
Plants Database 2018). Duvernoia gigantophylla has there-
fore been left untreated, neither synonymized nor transferred,
and essentially lost to science for over 100 years.
Since the rst collection of this species in 1898 and the
subsequent type specimen of 1911, no more specimens were
collected until the 1960s (all of which were then mis-iden-
tied as either J. extensa or J. laxa). In most herbaria, this
species has eectively been synonymised under J. laxa s.
lat., due mainly to it having glabrous ovaries/capsules, the
primary characteristic used by Burkill & Clarke (1900) and
Heine (1963, 1966) to dierentiate J. laxa from J. extensa
552
Pl. Ecol. Evol. 152 (3), 2019
(the latter having pubescent ovaries/capsules). Some of the
earliest specimens of D. gigantophylla (e.g. Zenker 1840)
were labelled as “Justicia andersonii Lindau”, a name that
was subsequently applied in 2004 to other specimens of this
species by D. Champluvier (then of BR) who agreed that this
species is distinct from J. laxa. However, J. andersonii is an
unpublished manuscript name and would in any case be an
illegitimate later synonym of D. gigantophylla (the name
J. andersonii has already been published for two other spe-
cies: Justicia andersonii Ramamoorthy from India and Jus-
ticia andersonii Wassh. from Brazil). The rediscovery of this
species in 2014 and again in 2015, and observations on its
unusual litter-gathering habit, prompted the re-examination
of its taxonomic status which has led to its resurrection and
transfer to Justicia here.
Recent molecular phylogenetic studies (Kiel et al. 2017,
2018) have demonstrated that Justicia s. lat. is highly para-
phyletic and have outlined the need for serious re-evaluation
and revision of the generic delimitation within the “justi-
cioid” lineage. However, as the sampling in those studies
was insucient to reach rm conclusions on revised generic
circumscriptions, a broadly circumscribed Justicia will re-
main for the immediate future, but it also seems likely that it
is only a matter of time before major updates are implement-
ed. What is clear from the results of Kiel et al. (2017) is that
Duvernoia sensu Lindau is polyphyletic. Included in their
sample are both J. extensa and J. aconitiora (A.Meeuse)
Cubey, the latter taxon being one of the two species previ-
ously treated in Duvernoia s.s. (see Manning & Getlie-Nor-
ris 1995) and closely allied to the type species D. adhato-
doides E.Mey. ex Nees (= J. adhatodoides (E.Mey ex Nees)
V.A.W.Graham). Justicia extensa and J. aconitiora are re-
solved as not closely related in this phylogeny. Hence, even
if Justicia s. lat. is eventually broken up into segregate gen-
era and Duvernoia is resurrected, the name D. gigantophylla
will not stand. Therefore, it is appropriate that this species is
transferred to Justicia s. lat. pending future generic recircum-
scription.
Besides the progress made with J. gigantophylla, it is clear
that further work is necessary to resolve the J. extensa-laxa
complex with any satisfaction. Molecular analysis would be a
helpful addition here and may oer a logical and informative
next step in the study of this group.
Litter-gathering habit
The distinctive litter-gathering habit of J. gigantophylla im-
mediately separates it from the non-litter gathering species
with clearly petiolate leaves seen across the rest of the J.
extensa-laxa complex. The large leaves are tightly clasped
around the stem and, due to the short internodes towards
the stem apices, the opposite-decussate pairs form together
a pseudo-rosette which creates a basket-like eect that col-
lects humus and leaf litter from the forest. This habit appears
to be unique in Acanthaceae though it has evolved in many
dierent families (Zona & Christenhusz 2015; Lachenaud
& Jongkind 2013) and may represent a remarkable case of
convergence. The precise role of this adaptation remains
unclear for J. gigantophylla, though in other litter-gather-
ing plants commensal organisms are believed to utilise the
caught debris as food and/or housing, whilst the host plant
benets from nutrients as this debris is broken down (Zona
& Christenhusz 2015). Litter-gathering plants such as this
are surprisingly understudied, especially as far as Africa is
concerned. It appears that they are often gregarious, with a
strong tendency for several litter-gathering species to grow
together (Lachenaud & Jongkind 2013). The reasons for this
are unclear, but the litter-gathering habit may represent an
adaptation to nutrient-poor soils. Nutrients might also be
absorbed by the stem epidermis, or by underground roots as
debris is washed away to the base of the plant (Hawthorne
2013). Cheek et al. (2008) described Psychotria kupensis
(Rubiaceae), another litter-gathering shrub from Central Af-
rica. Much like J. gigantophylla, this species was noted by
the author for gathering forest litter in “funnel-like” rosettes,
which indeed remains preserved in some herbarium speci-
mens. Cheek et al. suggest that this litter-gathering form may
benet the plant through the uptake of “nutrient-enriched
rainwater that percolates down from the funnel” (Cheek et
al. 2008: 244); it is likely that a similar process occurs in J.
gigantophylla.
ACKNOWLEDGEMENTS
This research was supported by grants from the Emily Hol-
mes Scholarship and the Systematics Research Fund. The
authors would like to thank the Systematics Association,
the Linnaean Society and the patrons of the Emily Holmes
Scholarship for their generosity and support. We also thank
Andrew Brown for illustrating Justicia gigantophylla.
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Communicating Editor: Elmar Robbrecht
Submission date: 4 Mar. 2019
Acceptance date: 9 Sep. 2019
Publication date: 28 Nov. 2019
