Orthotrichum mazimpakanum sp. nov. and O. anodon

(Orthotrichaceae), two similar species from California

Ricardo Garilleti1,5, James R. Shevock2,3, Daniel H. Norris3, andFrancisco Lara4

1 Departamento de Botanica, Facultad de Farmacia, Universidad de Valencia, Avda.Vicente Andres Estelles s/n E-46100 Burjassot, Valencia, Spain; 2 Department of

Botany, California Academy of Sciences, Golden Gate Park, San Francisco,California 94118-4503, U.S.A.; 3 University Herbarium, University of California,

1001 Valley Life Sciencies Bldg., 2465, Berkeley, CA 94720-2465, U.S.A.;4 Departamento de Biologıa (Botanica), Facultad de Ciencias, Universidad

Autonoma de Madrid, c/ Darwin 2, E-28049 Madrid, Spain

ABSTRACT. Studies of herbarium samples and field surveys in Southern California during the fall of

2008 led to the discovery of several new collections of mosses lacking exostome teeth belonging to

Orthotrichum Hedw. subgenus Pulchella (Schimp.) Vitt. Some of them are ascribable to O. anodon

F. Lara, Garilleti & Mazimpaka even though they display a set of characters not noticed before,

considerably broadening the morphological variability of this species and making necessary an

updated description. Other materials, from scattered localities along a wide latitudinal range,

correspond to a here described new species, Orthotrichum mazimpakanum Garilleti & F. Lara,

differentiated by a set of unambiguous characters, including almost smooth, hyaline endostomial

segments and partially bistratose leaves. Both mosses are illustrated with SEM and LM

photographs, and their similarities and differences are discussed.

KEYWORDS. Mosses, peristome, subgenus Pulchella, Taxonomy, Western North America.

¤ ¤ ¤

When examining and revising the collections of the

genus Orthotrichum Hedw. at UC and CAS, we found

some specimens of subgenus Pulchella (Schimp.) Vitt

with single peristomes composed only of endostome

segments. The only North American moss of this

group known to have this character was O. anodon F.

Lara, Garilleti & Mazimpaka, but some specimens

could not be attributed to this species. Since the

available material for study was not especially rich,

we decided that new collections from the known

localities as well as exploration of new areas were

needed. A survey in Southern California provided

abundant material from which it was clear that the

initially detected morphological variability actually

corresponded to two different species. One of them,

found only in one locality near the Mexican border,

was O. anodon, although new traits and some

variations in the size of some structures were

observed. This is understandable, because the

original description of this moss was based only on

5 Corresponding author e-mail:

ricardo.garilleti@uv.es

DOI: 10.1639/0007-2745-114.2.346

The Bryologist 114(2), pp. 346–355 0007-2745/11/$1.15/0Copyright E2011 by The American Bryological and Lichenological Society, Inc.

the very scarce material that constitutes the species’

holotype (Garilleti et al. 2006), but it makes necessary

to update the description. The rest of the material

collected from four localities from northern, central

and southern California belong to a new species,

Orthotrichum mazimpakanum, described here. Both

species can be reliably distinguished as follows:

- Endostomial segments very apparent when dry, whitish,

strongly papillose, usually in number of 16, widely covering

the mouth; capsule mouth star shaped when dry; vaginula

naked or with scattered thin and smooth hairs; lid convex,

mucronate, without differentiated basal rim; leaf margin and

lamina unistratose ................................................ O. anodon

- Endostomial segments inconspicuous when dry, hyaline,

smooth, usually in number of 8, sparse around the mouth;

capsule mouth rounded when dry; vaginula hairy, with thick

papillose hairs; lid slightly convex and short rostrate, with a bright

orange rim; leaf margins bistratose, upper leaf lamina partially to

almost completely bistratose ...................... O. mazimpakanum

THE SPECIES

Orthotrichum anodon F. Lara, Garilleti &

Mazimpaka in Garilleti, F. Lara & Mazimpaka,

Bryologist 109: 188. TYPE: U.S.A., CALIFORNIA. Los

Angeles Co., Palmer Canyon, 5 miles north of

Claremont, shaded side of Quercus agrifolia, Alt.

Figures 1–7. Orthotrichum anodon. 1. Mature capsule when dry showing the white segments. 2. Lateral view of a capsule with the

dome shaped operculum. 3. View of a mouth cancelled by the segments. 4. A detaching operculum with view of peristome below it.

5–6. Views of the endostome under the light microscope. 7. Ochrea and vaginula with thin, uniseriate and smooth hairs. (All from

Lara et al., San Diego Co., Campo Indian Reservation).

Garilleti et al.: Orthotrichum mazimpakanum sp. nov. from California 347

348 The Bryologist 114(2): 2011

2.000 [ft.], N.C. Sweet 33, III/12/41 (Holotype

FH!). Figs. 1–12

Description. Plants to 0.5 cm tall, generally

scarcely branched, olive-green, scattered or in small

cushions. Stems orange brown, more or less

pentagonal in section. Axillary hairs formed up to 14

rectangular hyaline cells, the basal 1–2 shorter and

somewhat colored. Rhizoids orange brown, smooth,

at stem base. Leaves erect-appressed, curved and

somewhat homomallous, slightly flexuouse when dry,

erect and flexuose when moist, ligulate, lanceolate to

ovate-lanceolate, slightly keeled, (2.0–)2.5–3.3 3

(0.5–)0.6–1.0 mm; lamina unistratose; leaf apex acute

to subacute, frequently cochleariform. Leaf margin

entire, unistratose, strongly recurved on both sides

from next to base to near apex, where it become

plane or erect. Costa ending shortly below apex,

rarely percurrent, 57–80(–100) mm width at leaf base,

(30–)35–55 mm at mid leaf. Basal leaf cells

rectangular, (14–)20–47(–51) 3 8–15 mm, smooth,

with non-nodulose cell walls, somewhat thickened, at

margin almost quadrate, 11–14 mm. Median and

upper leaf cells isodiametric or oblate, (8–)10–18

(–25) 3 (9–)10–16(–19) mm, somewhat bulging,

generally smooth, rarely with 1(–2) very low and

weak papillae in young leaves which tend to

disappear in mature ones. Brood bodies not seen.

Cladautoicous. Perigonia pseudolateral, terminal on

short or long branches. Sporophyte immersed to

emergent. Seta 0.3–0.5 mm, covered by ochrea.

Vaginula naked or with a variable number of thin,

smooth, uniseriate hairs, rarely with isolated biseriate

cells. Capsule 1.4–1.625 mm long, cylindric,

progressively narrowing to seta when dry, also

cylindric but sharply narrowing to seta when moist,

pale brown, darker at mouth, which is puckered and

star-shaped. Exothecial cells pale, irregular in shape,

with walls weakly thickened. Exothecial bands usually

very short, well differentiated, somewhat darker than

the rest of the exothecium, reaching the mouth and

extending some more than 10% of capsule length (ca.

150–200 mm), formed by (2–)3–4 cell rows in width

and 5–6 cells in length, with quadrate to shortly

rectangular cells, (18–)22–35(–50) 3 (15–)22–32

(–37) mm, with thickened cell walls; exceptional

specimens have longer bands weakly differentiated in

lower part. Stomata cryptoporous, located in the

lower capsule third (urn base and neck), entirely

covered by prominent and thick walled exothecial

cells. Peristome formed by a well-developed

endostome and frequently with remnants of teeth.

Exostome null or only constituted by the 2–3 basal

cells of 16 very rudimentary teeth, not or scarcely

protruding from capsule mouth, whitish, delicate,

roughly papillose in the outer side, smooth or with

thick lines and papillae in the inner side; sometimes

the exostome can be seen as a whitish low ring

around the capsule mouth. Endostome very

conspicuous, formed by 16 moderately strong,

whitish, opaque segments (becoming hyaline in very

old material), up to 300 mm in length, sometimes

appendiculate in the lower third, strongly ornamented

on both sides, the Primary Peristomial Layer (PPL)

biseriate, covered by thick papillae and papillose lines,

the Inner Peristomial Layer (IPL) uniseriate, more

openly and homogeneously spotted with simple

papillae. Connective membrane usually complete, 1–2

cells high, with the same ornamentation as IPL.

Operculum convex, dome-shaped, mucronate,

without basal rim, 0,5–0.7 mm in diameter. Calyptra

conic, golden-yellow with orange tip, slightly plicate,

1.7–2.0 mm, smooth even in the plicae, with long,

smooth, thin hairs, uniseriate or rarely partially

biseriate, more abundant at apex. Spores reddish-

brown, finely papillose, 15–21 mm in diameter.

Distribution and ecology. Orthotrichum anodon

is only known from two localities from Southern

California (Fig. 32), the new one near the border with

r

Figures 8–12. Orthotrichum anodon. 8. SEM view of the upper part of a capsule, showing the star-shaped mouth and the incurved

endostome segments. 9. Endostome segment showing the well developed ornamentation on both sides; part of the connective

membrane can be seen at segment base and at right. 10. Detail of the basal external side of endostome, showing a pattern of

papillose longitudinal lines and some scattered papillae. 11. Base of a segment flanked by a pair of fragments of roughly papillose

exostomial teeth, observed from the outside. 12. Inside view of a tooth fragment (left, almost smooth) and a segment (right,

densely papillose). (All from Lara et al., San Diego Co., Campo Indian Reservation).

Garilleti et al.: Orthotrichum mazimpakanum sp. nov. from California 349

Mexico, making its presence in Baja California very

likely. In both localities the species was found only on

Quercus agrifolia in Mediterranean type forests.

Discussion. Due to the scarcity of the original

material from which this species was described

(Garilleti et al. 2006), some traits of the moss could

be only superficially studied, the variability of some

others only partially considered and, finally, some

characters were absent from the holotype. This

revised and expanded description updates the

morphological variability of several qualitative

characters, namely: 1) color, structure and

ornamentation of the endostome; 2) the frequent

presence of basal fragments of a very incomplete

exostome; 3) the vaginula hairiness (originally

described as naked, the vaginula usually has thin

smooth hairs). On the other hand, the variability of

both leaves and leaf cells sizes is greater than

described in the protologue. Besides this, rare

specimens have exothecial bands longer than those

from the type. These bands have two parts clearly

different: the upper part, close to the mouth, is

regular: broad, formed by 3–4 rows of well

differentiated cells; immediately below this area the

bands become thinner and poorly developed, formed

just by 2(–3) rows of scarcely differentiated cells, and

extended along the middle 1/3 of capsule although

this prolongation does not affect the capsule shape

when dry. Despite our increased knowledge of the

morphological variability of this noteworthy moss,

Figures 13–19. Orthotrichum mazimpakanum. 13. Habit. 14. Two capsules displaying the reduced peristome and the urceolate

capsule with well-marked ribs; segments are hyaline even when dry but they are lost in old capsules (right). 15. Lateral view of a

capsule with the slightly convex and rostrate operculum; note the orange basal rim. 16. Lateral view of the upper part of a mature

capsule. 17–18. A pair of leaves showing somewhat different shape, the left one with abundant bistratose stripes on the upper two

thirds of lamina. 19. Leaf section with thickened margins. (13–17 from holotype; 18–19 from Norris 23500).

350 The Bryologist 114(2): 2011

the species concept expressed in the protologue

(Garilleti et al. 2006) remains basically valid.

Additional specimens examined. U.S.A.

CALIFORNIA: San Diego Co., along Hwy. 94 at junction of

road to Outdoor World Campground ca. 3 miles east

of La Posta road, 32u399N 116u239W, elev. ca. 1.000 m,

on fairly moist, diffusely lit bark of Quercus in Q.

agrifolia riverine, 28 Feb 1992, D.H. Norris 77802 (UC);

San Diego Co., Campo Indian Reservation, along

Campo creek, 3 miles east of La Posta road, Hwy 94 at

road marker 59, 32u32957.300N 116u22943.830W, on

Quercus agrifolia in Q. agrifolia woodlands, 15 Nov

2008, F. Lara. R. Garilleti & J.R. Shevock (CAS, VAL,

Herbarium at Universidad Autonoma de Madrid).

Orthotrichum mazimpakanum Garilleti & F.

Lara, sp. nov. Figs. 13–31

Planta parva foliis lanceolatis, obtusis, ad marginem

incrassatis, lamina cum fascibus vel areis bistratis

in superiore parte. Capsula cylindrica, laeviter

sulcata, 8 striis in tercio superiore dispositis.

Stomata cryptopora, in capsulae tertio inferiore

Figures 20–25. Orthotrichum mazimpakanum. 20–21. Exothecial bands; the band cells are more differentiated in the upper part of

capsule; note the well differentiated small rounded cells in a ring immediately under the mouth (very conspicuous between bands) that

maintain the mouth widely opened when dry. 22. Detail of an endostome segment. 23. Partial view of the endostome. 24. Ochrea and

vaginula with thick hairs. 25. Detail of a pluristratose and papillose vaginula hair. (20, 21, 23 from holotype; 22, 24, 25 from Harpel 992).

Garilleti et al.: Orthotrichum mazimpakanum sp. nov. from California 351

352 The Bryologist 114(2): 2011

confinata. Peristoma simplex, endostoma 8 vel

8+n hyalinis fragilibusque, laevibus segmentis

munitum. Operculum convexum, breviter

rostratum, aurantiacum in basi. Calyptra cum

pilis multiseriatis atque papillatis munita.

TYPE. U.S.A. CALIFORNIA: Riverside Co., San Jacinto

Mts., San Bernardino National Forest, Bay Tree

Spring, Hwy 243, 33u499100N 116u479210W,

1630 m a.s.l. On base of Quercus chrysolepis in

the edge of a Quercus forest, 16 Nov 2008, F.

Lara. R. Garilleti & J.R. Shevock (holotype UC,

isotypes CAS, VAL, Herbarium at Universidad

Autonoma de Madrid).

Description. Plants to 1.2 cm tall, variably

branched, dark green, brown in basal part, scattered or

in cushions up to 1.5 cm. Stems orange brown, more

or less pentagonal in section. Axillary hairs formed by

up to 9 rectangular hyaline cells, the basal 1–2 shorter

and somewhat colored. Rhizoids orange brown,

smooth, densely disposed in the lower half of stems,

scattered and distinctly shorter upwards. Leaves erect-

appressed, somewhat homomallous when dry, patent

to spreading and somewhat flexuose when moist,

slightly keeled, lanceolate to ovate-lanceolate, rarely

ligulate, (1.1–)1.5–3.4 3 0.4–0.8(–0.9) mm; upper

leaves larger than the lower ones. Leaf apex obtuse,

sometimes broadly acute or rounded obtuse. Leaf

margin entire, recurved in lower part, commonly

asymmetrically on both sides, sometimes one of the

margins recurved up to 4/5 of leaf length; unistratose

below, in central and upper part usually thickened, to

form a bistratose, rarely tristratose, border 2(–3) cells

deep and 2–3(–4) cells wide. Lamina unistratose

below, in the central and upper part variably bistratose

between populations, individuals and leaves, at one

extreme with scattered bistratose stripes, at the other

almost completely bistratose. Costa ending shortly

below apex, (50–)70–120(–140) mm width at leaf base,

(30–)40–60 mm at mid leaf. Basal leaf cells rectangular,

with slightly thickened, smooth walls, (15–)19–42(–

45) 3 (6–)10–17(–19) mm, marginal cells shorter 9–

17(–20) 3 10–16 mm, with somewhat thickened walls,

frequently with quadrate or oblate lumina in the two

more external cell rows. Median and upper leaf cells

irregularly rounded, ellipsoids or oblate, (7–)9–15

(–17) 3 7–14(–16) mm, walls more or less thickened,

with 1–2(4) low, simple, rarely apically bifurcate

papillae per cell in both leaf surfaces; usually cells from

unistratose areas have 1–2 papillae whereas those from

bistratose areas have 3–4 papillae. Brood bodies

brown, cylindrical, variable in length, sometimes

ramified, present especially on deteriorate leaves.

Cladautoicous, with perigonia on the main stem and

perichaetia on lateral branches. Sporophyte immersed

to shortly emergent. Seta 0.5–0.8 mm, long covered by

the ochrea. Vaginula hairy; hairs usually partially or

Figure 32. Map of California showing the known distribution

of Orthotrichum mazimpakanum (stars) and O. anodon

(diamond: type locality, dot: new locality here reported).

r

Figures 26–31. Orthotrichum mazimpakanum. 26. SEM view of the upper part of a capsule with a complete endostome of eight

segments. 27. External view of an endostome segment. 28. Inner side of a segment, showing the trabeculae and the weakly papillose

surface. 29. A fragment of the faintly papillose connective membrane. 30. A very unusual ornamentation consisting of patches of

papillae on the external side of a segment. 31. Detail of the inner side of the same segment ornamented with distinct papillae. (All

from holotype).

Garilleti et al.: Orthotrichum mazimpakanum sp. nov. from California 353

totally biseriate and papillose. Capsule 1.3–1.7 mm

long, cylindric or more typically long urceolate when

dry, broadly cylindric when moist; sharply narrowing

to seta through a short neck; mouth not or scarcely

contracted, ring-shaped. Urn variably sulcate when

dry, in young capsules uniformly colored and ribbed

in the upper third, in old capsules frequently with dark

mouth and sulcate throughout. Exothecial cells

quadrate to shortly rectangular, well differentiated

below mouth in an annular ring of five rows of oblate

cells with thickened walls and in eight longitudinal

exothecial bands, formed basically by 2–3 columns of

cells (20–)25–40(–45) 3 (15–)20–26(–28) mm, but

locally each cell can duplicate giving an irregular

aspect to the band; bands are marked in the upper

third, where cell walls are thicker and somewhat

colored, whereas in central and lower part of the urn

they become weakly differentiated. Stomata

cryptoporous located in the lower capsule third (urn

base and neck), entirely covered by prominent and

thick walled exothecial cells. Peristome simple,

without exostome. Endostome generally formed by 8

delicate segments up to 240 mm long, hyaline, thin,

sometimes appendiculate, with well marked

trabeculae, on the outer side (PPL) irregularly

biseriate, smooth or very rarely with patches of thin

and dense papillae, on the inner side (IPL) smooth or

rarely weakly papillose below, sometimes with stout

papillae; rarely with some intercalary segments,

uniseriate and shorter than the principal ones.

Connective membrane almost absent, constituted by

tiny fragments 1(–2) cells high, smooth or more rarely

papillose. Operculum slightly convex and short

rostrate, yellowish with a bright orange rim, 0.4–

0.5 mm in diameter. Calyptra 2.0–2.4 mm long, fully

covering the capsule, conic, yellowish with an orange

beak, plicate and hairy, smooth except on plicae and

hairs which have single or ramified papillae; hairs

biseriate, rarely uniseriate. Spores reddish-brown,

finely papillose, 10–16 mm in diameter.

Etymology. We named the new species after

Vicente Mazimpaka, colleague and faithful friend, as

a tribute for his achievements in Bryology,

particularly in the study of the genus Orthotrichum.

Distribution and ecology. Orthotrichum

mazimpakanum is currently known from four

Californian localities (Fig. 32), in Riverside, Santa

Barbara and Humboldt counties. Except for the

northernmost one these correspond to areas covered

by Quercus agrifolia woodlands that are ecologically

quite similar and are influenced by a Mediterranean

climate with high summer temperatures and

prolonged summer drought. The locality from

Humboldt County marks the northern limit, where

the dominant vegetation corresponds to redwood

forest and montane hardwood. The climate is

generally milder with summers not as dry compared

to those occurring in Southern California. Additional

occurrences of this remarkable species are expected

to be discovered with continued field inventory and

collecting efforts.

Discussion. The peristomial reduction is,

undoubtedly, the most striking feature of

Orthotrichum mazimpakanum. Moreover, the exact

peristomial constitution of this moss, with almost no

exostome and well developed endostome segments,

has been described only in three other Orthotricha in

the world: the phaneroporous O. acuminatum H.

Philib. from the Mediterranean Basin, and both the

cryptoporous O. karoo F. Lara, Garilleti &

Mazimpaka from South Africa and the Californian

O. anodon. Since O. karoo has hyaline awned leaves,

O. mazimpakanum can only be confused with the

sympatric O. anodon. Both species can be included

only in subgenus Pulchella sensu Lewinsky (1993),

because of the endostome constitution and the

cryptopore stomata. They also share the same general

appearance, and a similar capsule morphology,

stomata position and leaf shape. Nevertheless, the

differences are substantial, and the more outstanding

ones have been indicated in the introductory key. A

summary of the most significant differences between

O. mazimpakanum and O. anodon is presented in

Table 1.

The particular peristomial constitution of the

new species seems to be related to winter rainfall

climates, since this architecture has been reported

only from areas with Mediterranean type climate

(Garilleti et al. 2006; Lara et al. 2009). However, the

species concerned have developed different strategies

in order to regulate the spore release with such a

reduced peristome. Orthotrichum mazimpakanum

and O. karoo have thin endostome segments and a

widely opened mouth when dry, because of the ring

354 The Bryologist 114(2): 2011

of differentiated cells below it (Lara et al. 2009), and

the endostome seems unlikely to control spore

release under any conditions. The case is quite

different in O. acuminatum and O. anodon, where the

contraction of the mouth and its effective

cancellation by the endostome segments seem to be of

paramount importance, restricting the spore release

under dry conditions. A further discussion on the

implications that have exostome reduction and mouth

shape for the regulation of spores release can be found

in Lara et al. (1999) and Garilleti et al. (2006).

Additional studied specimens. U.S.A. CALIFORNIA:

Riverside Co., HWY 243 from Vista Grand Station,

T4S R2E Sec. 7, on tree trunk of Quercus chrysolepis,

elev. 4900’, 11 Apr 1980, J. Harpel 992 (CAS); Santa

Barbara Co., 4 miles west of east entrance to Los Padres

Natl. Forest, 35u059N 120u069W, 500 m, on moist,

diffusely lit base of Quercus wislizenii, 2 Feb 1994, D.H.

Norris 82233 & S. Piippo (UC); Humboldt Co., along

Bear Creek, Tolkan Recr. Area east of Shelter Cove,

D.H. Norris 23500 (UC).

ACKNOWLEDGEMENTS

We are grateful to the curatorial staff of UC, particularly Andrew

S. Doran and Kim Kersh, who in many ways contributed to

making the stay of FL and RG at the University Herbarium,

Berkeley, more comfortable and productive. They are also

thanked for the loan of some critical specimens, as well as for

sending our own collections from California to Spain. Debra

Trock, Collections Manager of CAS, is acknowledged for the

loan of further important materials. Finally, Dr. Jose Luis

Martınez Albertos kindly revised the Latin description. The

Spanish Ministry of Education and Science, Grant CGL2007-

61389 funded this work. RG and FL wish also thank the

University of Valencia and the Spanish Ministry of Education

and Science, respectively, for the grants that made their stay at

Berkeley possible.

LITERATURE CITED

Garilleti, R., F. Lara & V. Mazimpaka. 2006. Orthotrichum

anodon (Orthotrichaceae, Bryopsida), a new species from

California, and its relationships with other Orthotricha

sharing puckered capsule mouths. The Bryologist 109:

188–196.

Lara, F., R. Garilleti & V. Mazimpaka. 1999. Orthotrichum

acuminatum H. Philib. new to the Canary Islands. Journal

of Bryology 21: 75.

———, ——— & ———. 2009. Orthotrichum karoo

(Orthotrichaceae), a new species with hyaline–awned leaves

from southwestern Africa. The Bryologist 112: 194–201.

Lewinsky, J. 1993. A synopsis of the genus Orthotrichum Hedw.

(Musci, Orthotrichaceae). Bryobrothera 2: 1–59.

ms received July 5, 2010; accepted March 3, 2011.

Table 1. Summary of the differences between Orthotrichum mazimpakanum and O. anodon.

O. mazimpakanum O. anodon

Leaf margin thickness Incrassate (2-3-stratose) in upper part Unistratose

Leaf lamina thickness Unistratose below, with bistratose stripes to

almost completely bistratose in the upper lamina

Unistratose

Leaf cell papillosity 1–4 low, simple or bifurcate papillae Smooth, rarely 1(–2) very low, simple weak papillae

Leaf apex Obtuse, broadly acute or rounded obtuse Acute to subacute, frequently cocleariform

Brood bodies Cylindrical, sometimes ramified Not seen

Vaginula hairs (Uni-)biseriate, papillose Uniseriate and smooth

Calyptra Papillose on plicae Smooth

Calyptra hairs Thick, biseriate, papillose Thin, uniseriate, rarely partially biseriate, smooth

Operculum Slightly convex and short rostrate, with a bright

orange rim

Dome shaped, mucronate, without basal rim

Capsule mouth shape Rounded Contracted and star-shaped

Exothecial bands Long, up to 1/2 of capsule, 2(–3) cells wide,

not reaching the mouth

Short, restricted to upper part of urn, 3–4 cells

wide, reaching the mouth

Exostome Absent Absent or frequently very reduced (2–3 cells high)

Endostome 8(8+n) delicate, hyaline 16, strong, whitish

Segment ornamentation Smooth, rarely partially papillose Densely papillose on both sides

Connective membrane Incomplete, smooth Well developed, 2–3 cells high, papillose

Spore size 10–16 mm 15–21 mm

Garilleti et al.: Orthotrichum mazimpakanum sp. nov. from California 355