Niphotrichum elongatum
Grimmiaceae subfam. racomitrioideae
(1–)3–10(–13) cm, creeping, decumbent to ± erect, mostly pinnately branched with short, tuft-like branchlets, usually distinctly recurved at the apex.
creeping, ascending, to erect, central strand absent.
imbricate, not altered on drying, recurved when moist, ovate-lanceolate to subtriangular, indistinctly plicate, 2–3.2 × 0.8–1.2 mm;
margins broadly recurved throughout;
apices sharply carinate, most often piliferous, awns recurved to reflexed, subulate, strongly denticulate, mostly long-decurrent, slightly to distinctly papillose distally, strongly papillose basally with high and narrow papillae;
costa percurrent, situated at the base of a moderately deep, wide-angled channel and strongly flattened basaly, 75–100 µm wide;
basal laminal cells long-rectangular, 20–50 × 4–6 µm, moderately thick-walled, nodulose, papillose with large papillae, except for 1–4 rows of epapillose cells at the insertion;
alar cells hyaline, thin-walled in 3–5 rows, forming a sharply delimited, convex group;
supra-alar cells short, thick- and sinuose-walled, forming non-transparent border of 6–10 cells;
medial and distal laminal cells subquadrate to rectangular, 6–20 × 5–8 µm, distinctly papillose.
erect or spreading, straight or curved, sometimes recurved when wet, lanceolate to oblong-lanceolate, less often elliptic, ovate to lingulate, keeled to canaliculate-concave;
margins recurved to revolute, entire or erose-dentate, serrate or cristate at the apex, costa rarely spurred or forked distally, sometimes ending in mid leaf, subpercurrent or excurrent, smooth or papillose, in transverse section reniform to elliptical, sometimes semi-terete or strongly flattened, with (2–)3–15 adaxial cells near base, much larger than abaxial cells, often excurrent as an awn, awn smooth, or toothed or papillose or both;
laminal cells smooth, pseudopapillose, or papillose;
basal cells rectangular to linear, nodulose-porose, usually thick-walled, always with spiral thickenings forming a colored strip along the insertion;
mid leaf cells quadrate to elongate, mostly strongly sinuose-nodulose.
brown, glistening, 10–15 mm.
usually long, straight or rarely slightly arcuate, smooth or papillose, one to several per perichaetium;
vaginula with sinuose-nodulose epidermal cells.
dioicous.
brown, long-cylindric, 1.4–1.8 mm, sulcate when dry;
peristome teeth 650–800 µm long, reddish brown to red, split to the base into 2 filiform prongs, densely papillose.
erect, exserted, symmetric, ovoid, obloid to cylindric, usually smooth or obscurely striate;
stomates present;
annulus present, deciduous;
operculum long-rostrate;
peristome mostly with basal membrane and preperistome, equally thickened and weakly trabeculate both adaxially and abaxially, irregularly split into 2–3 branches to the middle or regularly divided into two filaments nearly to the base.
conic-mitrate, not plicate, often papillose at the apex, covering operculum to 1/2 of capsule.
9–11 µm.
perichaetial leaves hyaline, piliferous.
asexual reproduction very rare by gemmae arising from the base of the costa on the abaxial side.
Niphotrichum elongatum
Grimmiaceae subfam. racomitrioideae
Niphotrichum elongatum has only recently been formally described as a distinct species. Although it was distinguished at that level by several bryologists of the early eighteenth century, it subsequently fell into oblivion and was merged with N. canescens. It is very distinct, though closely related to N. ericoides. In contrast to the latter, it is a more southern taxon, and in North America does not extend to the Arctic, reaching its northernmost locality on Gilbert Island in southeastern Alaska. Apart from a few collections from the southernmost tip of Greenland, it has been found only once at lat. 70º N in East Greenland. It grows in habitats similar to those of N. ericoides, with which it often occurs in mixed stands, but the latter generally favours drier, warmer, and more exposed microhabitats than the former.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Genera 4, species ca. 75 (4 genera, 28 species in the flora).
Subfamily Racomitrioideae is characterized by a Racomitrium-type peristome, consistently sinuose-nodulose walls of the laminal cells and epidermal cells of the vaginula, absence of stem central strand, non-plicate calyptrae, and cladocarpous arrangement of the perichaetia. Taxa belonging to this subfamily have sometimes been associated with Ptychomitrium and Campylostelium, and placed in the subfamily Ptychomitrioideae in the Grimmiaceae. Despite their overall morphological similarity, these taxa seem to be only remotely related. In Ptychomitrium the laminal cell walls are straight or weakly sinuose, the calyptrae deeply plicate, and the plants acrocarpous. In addition, the preperistome is absent, and the peristome teeth lack trabeculae and have a characteristic air gap at their base. Moreover, Ptychomitrium is cryptoicous because the male branches are small and arise from the base of vaginula inside the perichaetial leaf circle. The Racomitrioideae consists of four genera that are segregates from the large and heterogeneous Racomitrium in the broad sense.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Laminal cells smooth or pseudopapillose; peristome teeth short, divided to the middle, rarely deeper, into 2-3 irregular prongs. | Bucklandiella |
1. Laminal cells papillose; peristome teeth long, split at least to the middle into 2(-3) filiform, ± regular filaments | → 2 |
2. Laminal cells with tall, conical papillae situated over the lumina; alar cells hyaline or yellowish hyaline, thin-walled, forming prominent, decurrent auricles. | Niphotrichum |
2. Laminal cells with large, flat papillae situated over the longitudinal walls; alar cells absent or distinct, brown to yellowish orange, not hyaline, thick-walled | → 3 |
3. Hyaline hair-point always present, usually long, strongly papillose eroso-dentate, long decurrent down the leaf margins; seta papillose, sinistrorse when dry; costa percurrent, unbranched; capsule slightly ventricose at base; calyptra smooth or minutely roughened. | Racomitrium |
3. Hyaline hair-point absent or present, rarely long, smooth to denticulate, never papillose or decurrent; seta smooth, dextrorse when dry (in C. fascicularis and C. corrugatus only once twisted to the left immediately below the capsule and proximally twisted to the left); costa ending well before the apex, often branched and spurred distally; capsule never bulging at base; calyptra distinctly verrucose to papillose. | Codriophorus |
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