A NEW, DISJUNCT VARIETY OF SPIGELIA GENTIANOIDES (LOGANIACEAE) FROM BIBB COUNTY, ALABAMA

5 Pages·1996·2.5 MB·English

by  Katherine Gould

A NEW, VARIETY OF
DISJUNCT
SPIGELIA
FROM
GENTIANOIDES (LOGANIACEAE)
BIBB
ALABAMA
COUNTY,
GOULD
KATHERINE
Department
Bntciny
of
The University Texas at Austin
of
TX
87
U.S.A.
Austin, 7
5,
1
w
variety of an endangered plant species, Spigelia gentianiodes
(
a
new
Tlie variety, differing largely in quantitative features,
.
Alabama,
discovered populations in central well disjunct fron
/
The new
Florida. populations are localized to a rare glade cor
on the Little Cahaba River and contain greater numbers of
te
i:
Logai
Spigelia gentianoides
,
,
A
new, disjunct group of populations of the Federally Endangered Spige-
(Loganiaceae) was discovered 1992 by James R. Allison of
gentianoides in
lia
Georgia Natural Heritage Program, Georgia Department of Natural
the
Resources, while exploring the Little Cahaba River in Bibb County, cen-
known
Alabama. This Spigelia species was previously only from several
tral
where
counties in the Florida panhandle, believed to be near extinc-
it is
tion from habitat loss (Krai 1983; Rogers 1986; A. Gholson, pers. comm.).
many
The Alabamian found with
Spigelia gentianoides in association
is
new and new unique
other rare plants, species varieties of plants in a dolo-
community known Ketona which encompasses
mitic glade the Glades,
as
over 40 outcrops of Upper Cambrian dolomite (Allison 1994a, 1994b).
These populations are not only geographically isolated from the Florida
populations, but their individuals also exhibit trait differences that signify
from Thus Alabama
genetic clifFerenciarion rhe Florida plants. the popula-
new
tions oi Spigelia gentianoides are here described as a variety.
Chapman DC.
Spigelia gentianoides ex A. alabamensis K. Gould,
var.
var. nov. (Fig.
1)
Similis Spigeliae gentianoidi var. gentianoides sea floribus majoribus, lobis corollarum patulis
per anthesin, sepalis longioribus, cymis plerumque brevioribus, lanceolatis aut
foliis
ellipticis.
cm
Perennial herb to 25 Stems usually several from the underground
tall.
rhizome, or of one main stem branching near the base, quadrangular, gla-
brous except at the nodes and ribs just below the nodes where scabrous.
Interpetiolar stipules minute, membranaceous. Leaves opposite, none
in
pseudowhorls below
the inflorescence, sessile, mostly lanceolate
to elliptic,
cm
occasionally ovate to obovate, the mid-stem leaves 2.8-3.5 long, 0.8-
cm
1.9 wide, longer than the internodes, the upper bracteate leaves smaller,
cm cm
1.6-1.9 long, 0.4-0.5 wide, the lowermost cauline leaves more
orbicular and smaller; the blades mostly acute to acuminate at the apex,
cuneate to rounded at the base, coriaceous, scarcely scabrous above, sca-
brous on the margins and veins beneath. a terminal 2~4(~6)
Inflorescence
mm
1-4
flowered cyme, the peduncles long, the bracts subulate, glabrous,
3
mm mm
long, the pedicels 2 long. Flowers 5-merous; subulate, tend-
sepals
mm mm
8-1
ing to be of unequal length, long at anthesis, accrescent 2 long
1 to
1
and exceeding the mature capsule at maturity, the tips acute, the margins
and midvein
scabrous; corolla broadly funnelform with plicate lobes, fleshy,
light pink outside with a green tinge at the base of the tube, two darker
mm
36-50
pink on each pink white
vertical lines lobe, lighter to inside,
mm
8-15 12-
long, the throat luide, the free portion of the lobes ovate, acute,
mm
13 with scabrous margins,
long, the lobes spreading open at anthesis; sta-
mm
mens
and style included; stamens epipetalous, borne 12-16 above the
mm
corolla base, the free filament 2 long, projecting inwards, the anthers
mm
mm
2-3 long, connivent around the style 1-2 below the stigmatic
surface and dehiscing onto the pubescent portion of the 24-27
style; pistil
mm mm
1-2
long, the ovary globose, long, green, glabrous, the white
style
mm
mm,
23—25 6—9
to yellow, slender, long, pubescent along the upper
mm
5-6
articulated above the ovary, the stigma terminal, truncate
to
mm
rounded, yellow, pubescent, less than wide. Capsule bilobed, slightly
1
mm mm
on
crested the top, glabrous, green, 8 high, 6 wide, the persistent
mm
style segment erect, dark brown, 5-6 long, the persistent, subtending
mm
base white, 6 long with emarginate
fruit
tips.
ALABAMA.
Typu: Bibb Co.: large Ketona dolomite glade on hillside above the Little
Cahaba River from County Road 65, off Hwy. 25, 30 May 1996, Katherine Gould 145 with
Gould TEX; GA, GH, UNA).
Sheryl (holotype: FLAS, FSU,
isotypes:
The most obvious difference between the two varieties flower size:
is
(36-50
Sptgelia gentianoides var. alabamensis has consistently longer corollas
mm mm
mm)
25-30 7-8 mm),
with broader (8-15 longer
throats
vs. vs.
mm mm
2-1 5-7 mm), (24-27 17-19 mm),
longer
lobes 3 vs. pistils vs.
1
(
mm
4-6 mm).
and longer sepals (8-1 vs. Furthermore, var. alabamensis
1
(2-4
generally produces shorter inflorescences than var. gentianoides flowers
3-8). The overall appearance of the flowers in the two taxa the same,
vs. is
when
except that the flowers of var. gentianoides barely open mature, thus
betwee
differ
:o
more
broadly
? c
pact, leathery habit with short intcrnodcs and asceiKhi^u leaves wirii the
margins curhni: found
leaf iij-'wards. In contrast, var. \^L-ut!.n}iiiiLs is Lisiially
under the shade of a pine-'niixed hardwood canopy or pine monoculture in
humous-
or duff-covered soil. In this environment generally has one thin,
it
weak
stem with elongate internodes and outspread However,
thin, leaves.
the var. gentianoides takes on the former habit when grown in full sun and
sandy Bok Tower Endangered Program
does Gardens' Plant
soil, as it at in
Lake Wales,
Florida.
much
Populations oi Sptgelia gentianoides var. alabamensis are larger in
number
and
extent of individuals than the present-day populations of
var.
some How-
gentianoides, with glades containing thousands of individuals.
new
ever, the variety appears to be entirely localized to these rare glade
communities, and should therefore be considered a rare plant in need of
am
James
I grateful to Allison for calling the nev./ Spigelia poptdations to
my
attention and providing feedback on this description, James Affolter
for his personal observations and helpful comments, Angus Gholson
for his
field assistance in Florida, Steven Ginzbarg for providing plant material,
Tammera
Race for access to the Endangered Plant garden at Bok Tower
Gardens and providing plant material, Billie L. Turner for academic advis-
ing and Gayle Turner and anonymous
editing, for the Latin diagnosis, an
comments
reviewer for on the manuscrint.
&
Ebinger
[.E. R. Szafoni. Proceec
USDA
vascular planes of the South. Fore
atecl
877-880.
J-TP2, Vol.
pp.
2,
G.K. 1986. The genera of Loganiaceae in
;rs,
i