Download 32 University of California Publications in Botany

32
University of California Publications in Botany
Almeda: Systematics of the
18 Cauline internodes and upper foliar surfaces covered with shaggy, plumose trichomes; principal
leaves ovate to ovate-elliptic, 7-9 plinerved abaxially, (1.3-)2.0-4.0 cm long; lower foliar surface covered with a mixture of plumose and sessile or stalked and stellate trichomes
15. M. pulchrum
18. Cauline internodes and upper foliar surfaces covered with distinctly barbellate (at least distally so) or
smooth trichomes; principal leaves elliptic, elliptic-lanceolate, ovate-lanceolate, linear-oblong, or
elliptic-ovate, 3-5-plinrtbrf snscislly, 2.0-2.5(-2.9) cm wide; lower foliar surface never covered with
a mixture of plumose and sessile or stalked, stellate trichomes.
19. Sprawling or decumbent, diffusely branched subshrubs, or slender, erect, suffrutescent perennials;
hypanthia covered with spreading, smooth trichomes and spreading, glandular trichomes.
20. Branchlets copiously hirsute; young branchlets held at an angle of 65-90°; principal leaves elliptic, elliptic-ovate, or ovate; mature hypanthia 7-9(-10) mm long; petals rounded to shallowly
emarginate apically; seeds dark brown, smooth, vernicose, tightly cochleate, somewhat semicircular, laterally compressed without a pronounced gyration; Panama . . . . 16. M. trichophyllun
20. Branchlets sparsely hirtellous; young branchlets held at an angle of 45° or less; principal leaves
ovate-lanceolate to linear-lanceolate; mature hypanthia (4-)5-6(-7) mm long; petals apiculate
apically; seeds orange-brown, minutely foveolate with a dull luster, cochleate to arcuate, with
conspicuous lateral gyration; Guatemala
17. M. tenellum
19. Erect, strictly to arcuately branched shrub; hypanthia covered with appressed, smooth or distinctly
barbellate trichomes (often intermixed with spreading, glandular trichomes).
21. Distal internodes sparsely hirtellous, quadrangular to subquadrangular with strongly carinate
to slightly winged expansions at the junction of adjacent stem faces; hypanthial trichomes
smooth (sometimes intermixed with glandular trichomes); uppermost floral bracts 1.1-1.8
(-2.5) mm long; style (9-)10-15(-17) mm long
2. M. calcaratum
21. Distal internodes moderately to copiously hirsute, ± terete; hypanthial trichomes barbellate,
often intermixed with spreading, glandular trichomes; uppermost floral bracts (l-)4-ll(-lS)
mm long; style-5-11 mm long.
22. Mature hypanthia campanulate to cylindric; flowers solitary or paired (rarely disposed in
dichasia); uppermost floral bracts elliptic, elliptic-lanceolate, or elliptic-ovate, 4-ll(-13)
mm long
12. M. deppeanum
22. Mature hypanthia urceolate to suburceolate; flowers borne in once- to thrice-compound
dichasia; uppermost floral bracts cordate, suborbicular, ovate, or spatulate, 1-6.5 mm long.
23. Principal leaves elliptic to elliptic-ovate (7-)9-2S(-28) mm long, (3-)4-ll(-13) mm wide;
internodal trichomes usually less than 1 mm long; sepals linear-oblong to lance-deltoid,
obtuse to rounded apically, 4-6 mm long; petals broadly elliptic to narrowly obovate,
rounded to oblique apically, 12.5-19 mm long
18. M. compactum
23. Principal leaves lanceolate to elliptic-lanceolate, (1.4-)2-4(-8) cm long, (4-)6-15(-29) mm
wide; internodal trichomes usually l-3(-5) mm long; sepals lance-triangular, acute apically, 3-5 mm long; petals ovobate, shallowly emarginate to retuse, rarely apiculate apically, 9-14 mm long
11. M. floribundum
iaceous, entire, or with stout, distally barbel
clasping, strongly decussate, held at right an
(-40) mm wide at the broadest point (usually t
glabrous, or more commonly with a single, lo
tween the impressed primary nerves traversin
present only along the foliar apex; lower leaf
glabrous, or with trichomes comparable to th
A
1. Monochaetum cordatum Almeda, sp. nov.
(Fig. 6)
Frutex erectus ad 3 m altus; rami glabri. Folia cordata, sessilia, Integra vel minute crenulata, glabra vel
sparsim strigosa, (l.l-)2-6.7(-9) cm longa et (8-)ll-32(-40) mm lata, 7-9(-ll) nervata, nervorum pari exteriore inconspicuo. Inflorescentiae terminales, dichasiales; bracteis ovatis vel lanceolato-ovatis, 5-23 mm
longis et 2-14 mm latis. Calycis lobi lanceolati, (4.5-)5-7 mm longi et 2-3 mm lati, persistentes. Petala rosea,
obovata, 1.6-1.9 cmlongaet 1.4-1.7 cmlata. Staminum maiorum filamenta 6-9 mm longa, thecis6.5-9(-10)
mm latis, appendicibus dorsalibus 4.5-5.5(-6.5) mm longis. Staminum minorum filamenta 8.5-10 mm longis, thecis 3.5-6 mm longis, appendicibus dorsalibus (2-)3-4 mm longis. Stylus 9-1S mm longus. Hypanthium
(maturum) plerumque glabrum, cylindricum, 6-9 mm longum et S-4(-5) mm latum. Semina 0.5 mm longa,
brunnea, minute foveolata, cochleata.
Erect, laxly branched shrub 1 -3-m tall. Cauline internodes glabrous, those of the young shoots indistinctly
quadrangular with two opposing flat to slightly concave faces, the remaining pair convex but becoming illdefined at the nodes and somewhat rounded with age. Nodal trichomes tufted, spreading, barbellate, less
than 1 mm long. Older stems woody, reddish brown, the bark exfoliating. Principal leaves thick, subcori-
H
Fig. 6. Monochaetum cordatum. A, habit, X
C, ovary and style (hypanthium removed), X 3; D
panthium and calyx lobes, X 3; F, seeds, X 18; G
Almeda 1330.)
orw in Botany
th shaggy, plumose trichomes; principal
12.0-4.0 cm long; lower foliar surface cov:llate trichomes
15. M. pulchrum
distinctly barbellate (at least distally so) or
olate, ovate-lanceolate, linear-oblong, or
e; lower foliar surface never covered with
omes.
or slender, erect, suffrutescent perennials;
md spreading, glandular trichomes.
t an angle of 65-90°; principal leaves ellip10) mm long; petals rounded to shallowly
licose, tightly cochleate, somewhat semiciration; Panama . . . . 16. M. trichophyllum
I at an angle of 45° or less; principal leaves
ithia (4-)5-6(-7) mm long; petals apiculate
th a dull luster, cochleate to arcuate, with
17. M. tenellum
:overed with appressed, smooth or distinctly
;, glandular trichomes).
,r to subquadrangular with strongly carinate
adjacent stem faces; hypanthial trichomes
trichomes); uppermost floral bracts 1.1-1.8
2. M. calcaratum
e, ± terete; hypanthial trichomes barbellate,
homes; uppermost floral bracts (l-)4-ll(-lS)
Almeda: Systematics of the Genus Monochaetum (Melastomataceae)
S3
iaceous, entire, or with stout, distally barbellate trichomes along the minutely crenulate margins, sessile,
clasping, strongly decussate, held at right angles to the stems, cordate, (l.l-)2-6.7(-9) cm long, (8-)ll-32
(-40) mm wide at the broadest point (usually the basal third), acute apically; upper leaf surface dark green,
glabrous, or more commonly with a single, longitudinal belt of appressed, distally roughened trichomes between the impressed primary nerves traversing the distal two thirds or half of the blade, or with trichomes
present only along the foliar apex; lower leaf surface light green or deeply pigmented, obscurely punctate,
glabrous, or with trichomes comparable to the upper surface but concentrated on and between the 9(-ll)
flowers solitary or paired (rarely disposed in
lliptic-lanceolate, or elliptic-ovate, 4-ll(-13)
12. M. deppeanum
; flowers borne in once- to thrice-compound
>orbicular, ovate, or spatulate, 1-6.5 mm long.
-)9-2S(-28) mm long, (5-)4-ll(-13) mm wide;
m long; sepals linear-oblong to lance-deltoid,
;; petals broadly elliptic to narrowly obovate,
ong
18. M. compactum
eolate, (1.4-)2-4(-8) cm long, (4-)6-15(-29) mm
) mm long; sepals lance-triangular, acute api>wly emarginate to retuse, rarely apiculate api11. M. floribundum
i Almeda, sp. nov.
:ssilia, Integra vel minute crenulata, glabra vel
mmlata, 7-9(-ll) nervata, nervorum pari exteribracteis ovatis vel lanceolato-ovatis, 5-23 mm
nlongiet2-3mmlati, persistentes. Petala rosea,
aiorum filamenta 6-9 mm longa, thecis 6.5-9(-10)
5. Staminum minorum filamenta 8.5-10 mm Iont mm longis. Stylus 9-13 mm longus. Hypanthium
gum et S-4(-5) mm latum. Semina 0.5 mm longa,
ies glabrous, those of the young shoots indistinctly
aces, the remaining pair convex but becoming ill'odal trichomes tufted, spreading, barbellate, less
: bark exfoliating. Principal leaves thick, subcori-
Fig. 6. Monochaetum cordatum. A, habit, X 14; B,H, abaxial surface of representative leaves, X ca. 1;
C, ovary and style (hypanthium removed), X 3; D,I abaxial surface of floral bracts, X SV£; E, mature hypamhium and calyx lobes, X3;F, seeds, X 18; G, petal, X 2 ^ . (A & F from Almeda 974A; B-E, G-I from
Almeda 1}}0.)
34
University of California Publications in Botany
elevated primary nerves; trichomes between primaries shorter and concentrated at the base of the blade.
Primary nerves diverging from a common point at the base of the blade, the outermost pair depressed and
usually evident only along the rounded base of the blade, becoming confluent with foliar margins distally.
Inflorescence terminal, laxly branched, (2-)3-4 times compound dichasium. Floral bracts reduced upward,
sessile, cordate to lance-ovate, glabrous above or beset with trichomes along the entire margins, glabrous
below or with scattered trichomes restricted to the primary nerves; lowermost bracts 9-nerved, 1.1-2.S cm
long, 6-12(-14) mm wide, uppermost bracts (5-)7-nerved, 5-ll(-14) mm long, (2-)S-5(-10) mm wide. Floral
pedicels 7-19 mm long, glabrous, erect at anthesis but often becoming strongly cernuous in fruit. Hypanthium (at anthesis) narrowly campanulate, commonly dark burgundy in color, occasionally with scattered,
appressed, distally roughened or barbellate trichomes (0.5-)l-2 mm long; hypanthial body glabrous with trichomes restricted to the external toral region at the base of the sepals. Hypanthium (at maturity) cylindrical, terete, or appearing obscurely 8-ribbed on drying, 6-9 mm long, 3-4(-5) mm wide. Sepals (on mature
hypanthia) usually spreading, narrowly lanceolate, ciliate, glabrous, without or with a few trichomes basally, (4.5-)5-7 mm long, 2-3 mm wide at the base, persistent. Petals pink with darker pink or deep red venation pattern, obovate, entire, commonly tipped with a single trichome, 1.6-1.9 cm long, 1.4-1.7 cm wide.
Antepetalous staminalfilaments 6-9 mm long; anthers deep red dorsally and suffused with yellow along the
ventral surface of the anther thecae, 6.5-9(-10) mm long, 1-1.5 mm wide, the apical pore 0.5 mm or less in
diameter; appendages yellow, but commonly white or translucent basally, clavate, 4.5-5.5(-6.5) mm long,
0.5 mm wide. Antesepalous staminal filaments 8.5-10 mm long; anthers yellow, 3.5-6 mm long, 1 mm or
less wide, the apical pore 0.5 mm or less in diameter; appendages yellow, narrowly elliptic and often irregularly lobed or notched apically, (2-)3-4 mm long, 0.5-1 mm wide. Ovary (at maturity) oblong to subcylindric, setose apically. Style 9-13 mm long. Seeds 0.5 mm long, light to coppery brown, minutely foveolate,
cochleate; n = 18.
Type. — PANAMA. Chiriqui Province; 2-2.5 km E of Cerro Punta and 1 km E of Bajo Grande, elev. 2200
m, December 23, 1971, Almeda 9 Wilbur 9T4A (Holotype, DUKE; isotypes, BM, BR, F, G, GH, K, LL,
MEXU, MICH, MO, NY, P, PMA, UC, US, W).
Flowering. — November through February and only sporadically from March through July.
Habitat and distribution. — Northern slopes and canyons adjoining Volcan Baru, Panama, and the northern foothills of the Cordillera de Talamanca E of Tapanti, Costa Rica. Restricted to roadbanks, pastu-elands, and steep, rocky slopes at elev. 1500-2500 m (fig. 7).
Monochaetum cordatum, one of two species known only from Costa Rica and Panama, is a well-marked taxon unlikely to be confused with other members of the genus,
It is readily recognized by its lax, dichotomously branched habit, sessile, prominently
nerved, cordate leaves, glabrous hypanthia, and cauline internodes. Aside from local
variations in foliar size, the species is uniform morphologically. Most populations
examined in the course of this study consist of few individuals, so it is not surprising
that M. cordatum was known from a single, fragmentary specimen prior to 1971. The
distinctive vegetative features of this species make it difficult to propose any close relatives. It is for this reason that I have chosen to place it in a species group of its own,
Trichome morphology supplies the only clue to a possible relationship between M. cotdatum and M. exaltatum. Both species share a trichome type which is smooth or gently
ridged basally and roughened or distinctly barbellate distally (fig. 1 M, N, O). This
trichome feature and the occurrence of natural interspecific hybridization (see discussion following) suggest a close relationship between these entities.
Sympatry. —At its only known Costa Rican locality in the vicinity of Orosi, M. cordatum grows with M. macrantherum and M. neglectum without apparent hybridization. If gene exchange is possible between these species, it is limited by the small population size of each taxon and by the fact that none has been found in contiguous
stands. In Panama, M. cordatum grows sympatrically with M. exaltatum and M.flonbundum. On one occasion I found it growing with single specimens of M. neglectun
and M. trichophyllum in the mountains northwest of Boquete. Approximately 2.5-3.0
ications in Botany
er and concentrated at the base of the blade.
>f the blade, the outermost pair depressed and
coming confluent with foliar margins distally.
und dichasium. Floral bracts reduced upward,
trichomes along the entire margins, glabrous
nerves; lowermost bracts 9-nerved, 1.1-2.3 cm
11(-14) mm long, (2-)3-5(-10) mm wide. Floral
i becoming strongly cernuous in fruit. Hypanburgundy in color, occasionally with scattered,
-2 mm long; hypanthial body glabrous with trithe sepals. Hypanthium (at maturity) cylindrirrni long, S-4(-5) mm wide. Sepals (on mature
glabrous, without or with a few trichomes basPetals pink with darker pink or deep red venae trichome, 1.6-1.9 cm long, 1.4-1.7 cm wide,
red dorsally and suffused with yellow along the
1.5 mm wide, the apical pore 0.5 mm or less in
lucent basally, clavate, 4.5-5.5(-6.5) mm long,
long; anthers yellow, 3.5-6 mm long, 1 mm or
lages yellow, narrowly elliptic and often irregu, wide. Ovary (at maturity) oblong to subcylinig, light to coppery brown, minutely foveolate,
> Punta and 1 km E of Bajo Grande, elev. 2200
, DUKE; isotypes, BM, BR, F, G, GH, K, LL,
adically from March through July.
adjoining Volcan Baru, Panama, and the north, Costa Rica. Restricted to roadbanks, pastu-e)•
known only from Costa Rica and Panused with other members of the genus,
[y branched habit, sessile, prominently
td cauline internodes. Aside from local
m morphologically. Most populations
• few individuals, so it is not surprising
igmentary specimen prior to 1971. The
ke it difficult to propose any close rela> place it in a species group of its own.
, a possible relationship between M. cortrichome type which is smooth or gently
.rbellate distally (fig. 1 M, N, O). This
tl interspecific hybridization (see discustween these entities.
locality in the vicinity of Orosi, M. corneglectum without apparent hybridizas species, it is limited by the small popuat none has been found in contiguous
itrically with M. exaltatum and M. floriwith single specimens of M. neglectum
west of Boquete. Approximately 2.5-3.0
36
University of California Publications in Botany
Almeda: Systematic*
km east of Cerro Punta, Panama, in a series of pasturelands extending less than half a
12
hectare, M. cordatum and M. exaltatum grow in an intermixed stand with morphological intermediates which are obvious products of interspecific hybridization. The
10
• •
two species differ markedly in diagnostic morphological characters (figs. 6, 27). Quali-1
tative features of foliage, floral bracts, and hypanthia differ markedly, but scatter diaUJ
gram portrayals also reveal differences in selected quantitative characters, displaying
the striking intermediacy of putative hybrids (figs. 8, 9). When qualitative characters
are codified (table 4) and summarized in the form of a hybrid index histogram, the re-'
• M. exoltotum
suiting pattern provides further insight into the morphological structure of the hybrid i
swarm (fig. 10). A large proportion of the intermediates appear to be early generation I
« Hybrids
S5
hybrids. Individuals comprising index classes 8 and 14/15 possibly represent early j
o M. cordatum
backcross derivatives to M. cordatum and M. exaltatum respectively. The remaining
assemblage of index classes may consist largely of F] and Fz hybrids, but assignment of
this status is admittedly arbitrary on the basis of morphological criteria alone.
0
2
The relationship between pollen viability and morphological intermediacy follows
LOWER
no discernible pattern (appendix 6). Individuals with index values of 5 and 8 have re- \d fertility percentages of 65 and 86
Fig. 9. Scatter diagram represent
show a gamut of variation. Some individuals in this class are sterile with pollen that is
aberrant in both shape and size; others have pollen that appears normal and comparable to that of the putative parents. The majority of putative hybrids in index
classes 11 through 15 appear normal and have viability percentages as high or higher
116
14
• ^. exaltatum
e Hybrids
• • •
•
• •
••
• • •e
•
0
00
0
0
«
than parental values. The cyto
nants in this hybrid swarm is u
ity and morphological interme
attributes are segregating and
bility of many hybrid plants i
gene flow back to one or both
M. cordatum
e
0
.0
0
0
0
50
o M. cordatum
45
0
tu
oc.
UJ
X
10
<
»
CO
0
30
0
e
a
O
o o
o o
UJ
o:
<
16
20
o
o
o
o
12
O
20
LEAF
24
28
32
36
10
40
2 3 4 5
W I D T H (mm)
Fig. 8. Scatter diagram representation of variation in Monochaetum cordatum, M. exaltatum,
and putative hybrids.
Fig. 10. Frequency distribution
Monochae
ications in Botany
asturelands extending less than half a
in an intermixed stand with morphots of interspecific hybridization. The
jlogical characters (figs. 6, 27). Qualinthia differ markedly, but scatter diaed quantitative characters, displaying
gs. 8, 9). When qualitative characters
m of a hybrid index histogram, the remorphological structure of the hybrid
nediates appear to be early generation
8 and 14/15 possibly represent early
•xaltatum respectively. The remaining
if F[ and Fz hybrids, but assignment of
of morphological criteria alone,
d morphological intermediacy follows
s with index values of 5 and 8 have reively. Others with an index value of 10
this class are sterile with pollen that is
pollen that appears normal and cornmajority of putative hybrids in index
viability percentages as high or higher
Almeda: Systematic* of the Genus Monochaetum (Melastomataceae)
37
12
i
•• .
E
~ 10
i
Io
z 8
bJ
e
o
X
I-
o
o
o
oo
o
• M. e x o l t o t u m
z
2
>
i
» Hybrids
o M. cordatum
3
4
LOWER
FLORAL
6
8
BRACT
10
12
WIDTH (mm)
Fig. 9. Scatter diagram representation of variation in Monochaetum exaltatum, M. cordatum,
and putative hybrids.
than parental values. The cytological basis for the reduced pollen viability of recombinants in this hybrid swarm is unknown. The lack of correlation between pollen viability and morphological intermediacy suggests that the genetic factors controlling these
attributes are segregating and recombining independently. Given the high pollen viability of many hybrid plants in this swarm it is difficult to account for the minimal
gene flow back to one or both parents.
• M. exdltotum
« Hybrids
o M. cordatum
50
M. e x a l t a t u m
45
30
20
o o
o
z.
10
24
28
32
36
10
0
40
I
2 3 4
5
6 7
8
9 10 II 12 13 14 15 16 17 18 19 20
HYBRID
W I D T H (mm)
INDEX
VALUE
Fig. 10. Frequency distribution of hybrid index values in the Panamanian population of
Monochaetum cordatum and M. exaltatum.
i in Monochaetum cordatum, M. exaltatum,
hybrids.
Almeda: Systematics of the (
Hybridization is presently occurrin
major impact on the variation pattei
exchange on the genetic and morphc
turn should be of utmost interest, for
logical events.
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Representative specimens. — COSTA RICA. Ca
(BM, DUKE, K, NY, US); Hwy #224 ca. 11.5
Wyatt 2170 (DUKE, US, W); Hwy #224 ca. 2
ca. 14-17 km E of Orosi, Luteyn 3946 (DUKE
at Tapanti, Wilbur 9 Luteyn 18486 (DUKE
Wilbur 7.5.50 (DUKE, US); Bajo Chorro trail
(DUKE, F, GH, MICH, MO, LL, UC); withou
Chorro trail from Paso de Respingo to Fila de
)837C (DUKE); trailside in Quebrado Bajo
13126A (A, DUKE, F, MEXU, NY, P, PMA
Cerro Punta, Wilbur et al. 1H94 (BR, CAS,
Nubes, Wilbur & Almeda 17070 (DUKE); ra
Cerro Picacho, Wilbur & Luteyn 19)87 (DU
Putative hybrids between Monochaetum co
E of Cerro Punta and 1 km E of Bajo Grande,
; .549 (DUKE, 6 plants), Almeda & Wilbur 1
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(DUKE, 7 plants); trailside in Quebrado Bajo
13126B (DUKE, 10 plants); ravine W of Las
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Arthrostemma calcaratum DC. Prodr. 3:138
Type. — MEXICO: State not given, Cordillera
PI; isotypes, BR1, GI [3 sheets], MOI, US!,
Rhexia calcaratum (DC.) Schlecht. Linnaea
Monochaetum enstferum Naudin, Ann. Sci.
Type. — MEXICO: Oaxaca, Ghiesbreght 219
Monochaetum candolleanum Naudin, Ann.
(nom illegit., ART. 63, I.C.B.N.) (Based o
turn [A. P. de Candolle] Triana).
Monochaetum oliganthum Naudin, Ann. Sc
Type. —MEXICO: Oaxaca, Ghiesbreght s.n.
Monochaetum naudinianum Neum. Rev. Ho
Type. —MEXICO: exact locality unknown,
breght (Holotype, not seen and perhaps no
Monochaetum pringlei Rose, Contr. U.S. Na
Type. —MEXICO: Morelos, Sierra de Tepoxt
isotypes, Al, F!, Gl, GHI, MEXUI, MICHI,
Monochaetum pringlei, f. latifolium Gleason
Type. —MEXICO: Morelos, canyons above C
type, Fl; isotypes, GHI [2 sheets], MICHI, M
Monochaetum remotum Gleason, Amer.J.Bo
Type. —MEXICO: Sinaloa, Sierra de Chaba
Erect, openly branched, virgate shrub 1.5drangular, slightly carinate or winged where
strongly canaliculate on drying. Branchlets to
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Almeda: Systematics of the Genus Monochaetum (Melastomataceae)
39
Hybridization is presently occurring at only one locality and appears to have had no
major impact on the variation patterns of either taxon. The long-term effect of gene
exchange on the genetic and morphological integrity of M. cordatum and M. exaltatum should be of utmost interest, for it will depend on a number of unpredictable ecological events.
Representative specimens. — COSTA RICA. Cartago: Hwy#224 ca. 20-24 km Eof Orosi, Almeda et al. 2)63
(BM, DUKE, K, NY, US); Hwy #224 ca. 11.5 km E of Orosi and just beyond Tapani!, Almeda, Flowers 9
Wyatt 2170 (DUKE, US, W); Hwy #224 ca. 20 km E of Orosi, Almeda et al. 2371 (DUKE, US); Hwy #224
ca. 14-17 km Eof Orosi, Luteyn 3946 (DUKE); steep banks of Rio Grande de Orosi ca. 12.9km SE of bridge
atTapanti, Wilbur 9 Luteyn 18486 (DUKE). PANAMA. Chiriqui: 2-2.5 km E of Cerro Punta, Almeda Si
Wilbur 1550 (DUKE, US); Bajo Chorro trail linking Boquete and Cerro Punta, Almeda 9 Wilbur 1598
(DUKE, F, GH, MICH, MO, LL, UC); without exact locality, Blum, Olson & Rasmussen 2421 (MO); Bajo
Chorro trail from Paso de Respingo to Fila de Respingo, Luteyn 3832 (DUKE); Bajo Chorro trail, Luteyn
3837C (DUKE); trailside in Quebrado Bajo Grande ca. 2 mi E of Cerro Punta, Wilbur, Teeri & Foster
D126A (A, DUKE, F, MEXU, NY, P, PMA, WIS); wooded slopes ca. 1 km N of Las Nubes and NW of
Cerro Punta, Wilbur et al. 15194 (BR, CAS, DUKE, UC, US); trail through cloud forest in vicinity of Las
Nubes, Wilbur 9 Almeda 17070 (DUKE); ravine W of Las Nubes ca. 5 km NW of Cerro Punta toward
Cerro Picacho, Wilbur & Luteyn 19387 (DUKE).
Putative hybrids between Monochaetum cordatum andM. exaltatum. —PANAMA. Chiriqui: ca. 2-2.5 km
Eof Cerro Punta and 1 km Eof Bajo Grande, Almeda 9 Wilbur 975 (DUKE, 26 plants), Almeda 9 Wilbur
J5«(DUKE, 6 plants), Almeda 9 Wilbur 1563 (DUKE, 6 plants), Almeda 9 Wilbur 974B (DUKE); Bajo
Chorro trail, Luteyn 3837B (DUKE); edge of forested slope above Cerro Punta, Wilbur et al. 10907B
(DUKE, 7 plants); trailside in Quebrado Bajo Grande ca. 2 mi E of Cerro Punta, Wilbur, Teeri 9 Foster
13126B (DUKE, 10 plants); ravine W of Las Nubes ca. 5 km NW of Cerro Punta toward Cerro Picacho,
Wilbur » Luteyn 19380 (DUKE).
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2. Monochaetum calcaratum (DC.) Triana, Trans. Linn. Soc. Bot. 28:63. 1871
Arthrostemma calcaratum DC. Prodr. 3:138. 1828.
Type. —MEXICO: State not given, Cordillera de Gutchillaque, October, 1827, Berlandier 997 (Holotype,
PI; isotypes, BRI, G! [3 sheets], MOI, US!, Wl [3 sheets]).
Rhexia calcaratum (DC.) Schlecht. Linnaea 13:431. 1839.
Monochaetum ensiferum Naudin, Ann. Sci. Nat. III. 4:50. 1845.
Type.-MEXICO: Oaxaca, Ghiesbreght 219 (Holotype, PI).
Monochaetum candolleanum Naudin, Ann. Sci. Nat. Bot. III. 4:51. 1845.
(nom illegit., ART. 63, I.C.B.N.) (Based on Arthrostemma calcaratum A. P. de Candolle, M. calcaratum [A. P. de Candolle] Triana).
Monochaetum oliganthum Naudin, Ann. Sci. Nat. III. 14:159. 1850.
Type.— MEXICO: Oaxaca, Ghiesbreght s.n. (Holotype, PI).
Monochaetum naudinianum Neum. Rev. Hort. 1861:211. fig. 1861.
Type. — MEXICO: exact locality unknown, described from cultivated material taken to Paris by Ghiesbreght (Holotype, not seen and perhaps nonexistent).
Monochaetum pringlei Rose, Contr. U.S. Natl. Herb. 8:327. pi. LXXII. 1905.
Type. - MEXICO: Morelos, Sierra de Tepoxtlan, 7500 ft., October 30, 1900, Pringle 8359 (Holotype, USI;
isotypes, Al, F], Gl, GHI, MEXUI, MICHI, MOI, NYI, PI, UCI, VTI, Wl).
Monochaetum pringlei, f. latifolium Gleason, Amer. J. Bot. 16:593. 1929.
Type.— MEXICO: Morelos, canyons above Cuernavaca, 6500 ft., November 1, 1896, {Cringle 7352 (Holotype, Fl; isotypes, GHI [2 sheets], MICHI, MOI, USI [2 sheets], VTI).
Monochaetum remotum Gleason, Amer.J.Bot. 16:593. 1929.
Type. — MEXICO: Sinaloa, Sierra de Chabarria, Ortega 4055 (holotype, USI).
Erect, openly branched, virgate shrub 1.5-4 m tall. Distal cauline internodes quadrangular or subquadrangular, slightly carinate or winged where adjacent faces intersect, at least two opposing faces becoming
strongly canaliculate on drying. Branchlets totally glabrous, or hirtellous and sparsely covered with widely
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