XX.  IWATSUKIELLA W. R. Buck & H. A. Crum, J. Hattori Bot. Lab. 44: 351. 1978 * [For Zennoske Iwatsuki, 1929--, Japanese bryologist]

                                                                                                            Judith A. Harpel

Plants small, slender, creeping yellowish green mats usually tightly attached to substratum.  Stems freely branched, prostrate, stoloniferous, foliose pseudoparaphyllia at base of leaves. Leaves concave, suborbicular to ovate-lanceolate with long-piliferous acumens; costa absent or short and double; margins plane to recurved, entire; medial cells short, thick-walled, rhombic to elliptic, smooth; alar cells not differentiated; stem and branch leaves similar.  Sexual condition dioicous. Capsules erect, oblong-cylindric, dark brown, exserted; peristome double.

Species 1 (1 in the flora):  North America, Asia.

Sporophytes are rare in North America. 

1.  Iwatsukiella leucotricha (Mitten ) W. R. Buck & H. A. Crum, J. Hattori Bot. Lab. 44: 352. 1978

Heterocladium leucotrichum Mitten, Trans. Linn. Soc. London, Bot. 3: 176. 1891

Stem leaves imbricate, slightly reflexed when moist, 0.5--1 x 0.3--0.4 mm. Seta 4--7 mm.  Capsules symmetric, 0.7--1 mm; exostome teeth smooth proximally, papillose distally, endostome rudimentary.  Spores 12--30 /um.

Trees, rock; low to moderate elevations; B.C.; Alaska, Wash., Oreg.; Europe (Russia, Georgia); Asia (China, Japan, North Korea).

In Washington and Oregon, Iwatsukiella leucotricha occurs on trees along fog-drenched coastal ridges.  Collections from British Columbia were made from trees in coastal bogs and swamps, but this species has been also collected on rock in Alaska.