Specimen #18: Timmia megapolitana

Collection #: 18

Scientific Name: Timmia megapolitana

Phylum: Bryophyta; Bryopsida

Order: Timmiales

Family: Timmiaceae; Timmiidae

Common Name: Warrior Moss

Location: Chagrin Falls Reservation

Habitat: On soil

Date of collecting: September 17th

Collector: Cornelia

Notes: Small straight tree like plant

How did I key this out:

Fig.1 Single plant with size

Fig.2 Group of plant with size

Fig.3 Leaf structure under microscope

Fig.4 Single plant under dissecting scope 

Fig.5 Cell structure under microscope

From both the group picture (Fig.2) and the picture of a single plant (Fig.1) above, we could easily tell that this specimen is a plant with the acrocarp growth form. From the leaf picture (Fig.3) we could see that this specimen is with lance-shaped leaves, and the leaves do have a midrib. By knowing these features, we could now go to the key: KEY II: Acrocarps with Lance-shaped Leaves.

The following steps is how I went through the keys:
1. (B) Plants darker green, yellow green, or brownish black, shoots loosely associated or if densely packed then not in domed mounds; leaves flat or folded but not tubular, with midrib usually visible at least at base of leaf. (See Fig.2 for this fact.) (3)
3. (B) Plants on soil, rocks, trees, or logs in dry areas, or if in wetter areas, not submerged in water; leaves not folded at base. (4)
4. (B) Leaf surface not rippled or wavy when wet. (9)
9. (A) Leaves mostly ≥4 mm long (some at base or tip of stem may be shorter). (10)
10. (A) Wet leaves flexible, thin, and translucent when held up to light; midrib obvious. (11)
11. (B) Leaf tips ending in tapered point; midrib apparent. (12)
12. (A) Leaf base sheathing stem, blade lance-shaped with parallel sides from the base to midleaf then tapering to the apex. (Timmia megapolitana, p.71)

Description of the specimen:
Appearance: Upright, unbranched, green to yellow-green plants standing 2-8 cm tall in loose tufts. When wet, the leaves spread widely from a sheathing base. Upon drying they draw doser to the stem, the edges roll inward, and the tips curl. Superficially the plants resemble an Atrichum but the capsules, which are nearly always present, are very different. 
Leaves: Lance-shaped, 4-8 mm long, gradually narrowed to a sharp point. Tiny teeth project from the edge and the midrib extends all the way to the tip.
Capsules: Oblong-cylindric, curved, 2-3 mm long, inclined to horizontal at the end of a 1-3 cm stalk. Lid is domed with a small nib. When the lid falls, revealing the teeth, they are a wonder to examine under the hand lens: each tooth has an erect thickened base and then bends inward at a right angle over the mouth of the capsule. The hood is tardily deciduous and often remains upright behind the capsule at the tip of the stalk, reminiscent of a single-feather Indian brave headdress. 
Habitat: On soil, humus, and rock in moist, shaded, calcareous sites.
Microscopic Features: Midleaf cells are rounded-hexagonal, green; basal cells are long-rectangular, yellow green to brown.

Collecting and keying story:

This specimen is very similar to my specimen #1 and #7 but smaller. After a long time not keying any mosses, I feel like I'm not familiar with them anymore... The teeth on the edge of the leaves of this specimen is really beautiful.

Phylum, order and family name cited from:
https://en.wikipedia.org/wiki/Timmia

Keys cited from:
Common Mosses of the Northeast and Appalachians by Karl B. McKnight, Joseph R. Rohrer, Kirsten McKnight Ward and Warren J. Perdrizet. This book is in the series of the Princeton Field Guides and was published by Princeton University Press with copyright @ 2013.