Salix eriocephala

Important Synonyms:
Common Names and Etymology: heartleaf willow (translation of Latin name S. cordata), Missouri willow (translation of name S. missouriensis), diamond willow (a willow susceptible to a fungus causing wood distortions, a name applied to a few different species). Its current Latin name was given by Michaux in connection with the presence of pine-cone midge (Rabdophaga) galls on the type specimens. These galls, however, are not species specific.

General Remarks
S. eriocephala is one of the most common and easily recognized willows in New England. According to Angelo & Boufford (2011), it is present in virtually every county of all the New England States, except for Martha's Vineyard Its geographic range extends across most of eastern North America. This is one of the most variable willows. The number of its synonyms, described varieties, and putative hybrids (only part of which are true hybrids) is enormous. It belongs to the largest subgenus of willows, Vetrix and has been attributed to either Sect. Cordatae (Argus 1999, 2010) or Hastatae—in case the latter section is understood in a broader sense, as Skvortsov (1999) did. These sections are comprised of numerous species both in North America and Eurasia, yet within southern New England, S. eriocephala is the only representative.
Similarly to all of its close relatives, S. eriocephala is a mid-sized shrub, though said to be occasionally capable of forming a small tree. Leaves are denticulate at margins, finely veined beneath, and with distinct, equilateral or subequilateral stipules. Pistillate catkins with glabrous ovaries/capsules that are gradually attenuate, forming a distinct style. Even though its name is heartleaf willow, the leaf blade is not always heart-shaped (cordate) at base.

Shrub 0.2-6.0 m tall [1] (very rarely small tree). Branchlets yellowish brown, generally flexible (occasionally somewhat brittle at base), pubescence variable (from velutinous to glabrate).
Buds yellowish brown, pubescent to glabrate, slender, broadening towards the base, with flattened beak. Inner membrane of bud scale completely free ("loose"), and falling off as a translucent "additional cap" with the bud development [2], [3], [4]. This is a unique feature, at least among the local species. Floriferous buds are visually different from vegetative, though the difference is not very drastic.
Leaves green or glaucous beneath, hypostomatous (i.e., stomata present only on under-surface); veins not forming conspicuous reticulum, though more obvious in mature leaves. Leaf shape varies from elliptic to narrowly oblong or even lanceolate; leaf base usually cordate, though may be rounded, or even cuneate; margin denticulate [5]. Immature leaves reddish or yellowish green, translucent [6], [7], glabrous or sparsely villous on both sides; mature leaves glabrous or glabrate, glaucous beneath (wax sometimes thin, so that leaves may appear green). Petioles without glands at junction with leaf blade. Stipules often well developed, prominent, equilateral to subequilateral, subcordate at base, rounded or acute at apex, glandular-serrulate at margins.
Catkins developing simultaneousely with leaves (coetaneous), borne on short leafy branchlets [8]. Stamens two (as in majority of our willows). Floral bracts persistent in catkin, colored brown except for pale base, same in staminate and pistillate catkins. Pistillate catkins 2.5-4.5 cm long, relatively densely flowered (though catkin rachis is visible). Ovaries greenish, frequently suffused with red [9], pyriform (pear-shaped), [10].

The plant is characterized by leaves that are often cordate at base, glabrous or glabrate beneath, and feature prominent stipules [11], [12], and glabrous ovaries/capsules borne on distinct stipes and subtended by bracts clothed with wavy hairs. Large leaves on upper (distal) parts of vigorous young shoots form characteristic regular "ladder-like" pattern [13], which can be noticed from the distance [14]. Young leaves at tips of developing shoots often attain bright pink or orange color [15], thus giving the species away. The reddish tint quickly fades, but mature leaves often retain pinkish midribs [16]. Bark on old trunks forms spectacular cracks [17].
Mature foliage can be confused with that of S. sericea, S. nigra, or S. x fragilis. S. eriocephala can be distinguished from S. sericea by branchlets flexible at base, loosely tomentose, becoming glabrate; also by presence of loose inner membrane in buds. Narrow-leaved S. eriocephala [18] can be confused with S. nigra. It differs from S. nigra in its bud scale forming a cap-like structure due to connate margins (calyptrate bud scale typical for most willows); from S. nigra and S. x fragilis, in petioles that lack glands at blade base, invariably hypostomatous leaves (stomata never present on upper leaf surface), and in its habit (only very rarely attaining tree stature).

Wetland Delineation Code for the species: FACW. A largely wetland shrub, not necessarily alluvial (water may be running or stagnate), occurring on gravelly or rocky river and stream banks [19], in mixed mesophytic woods on alluvium, at pond margins, in marshy fields and wet thickets; also at roadsides, especially if there is a ditch along a road.

Sources and References
1. Angelo R., D. E. Boufford D.E. 2011. Atlas of the Flora of New England. [ ...] (revised: Nov. 17, 2011)
2. Argus G.W. 1980. The typification and identity of Salix eriocephala Michx. Brittonia 32: 170–177.
3. Argus G.W. 1986. The genus Salix (Salicaceae) in the Southeastern United States. Systematic Botany Monographs 9. 170 pp.
4. Argus G.W. 1999. Classification of Salix in the New World. Version: 5 July 1999. Botanical Electronic News (BEN) # 227. [ ...]
5. Argus G.W. 2006. Guide to the Identification of Salix (Willow) in Illinois, Indiana, Ohio, and Pennsylvania. [ ...]
6. Argus G.W. 2008. A Guide to the identification of Salix (willows) in Alberta. [ ...]
7. Argus G.W. 2010. Salix L. in Flora of North America North of Mexico, Volume 7. Magnoliophyta: Salicaceae to Brassicaceae, pages 23-162. Eds. Flora of North America Editorial Committee. Oxford and New York: Oxford University Press. Online version: [ ...]
8. Skvortsov, A.K. 1999. Willows of Russia and adjacent countries. Taxonomical and geographical revision. Univ. Joensuu. Faculty of Mathematics and Natural Sciences Report Ser. 39. Joensuu, Finland. English translation of Skvortsov 1968. Ivy SSSR. Sistematicheskiy i geograficheskiy obzor [Willows of the USSR. Taxonomic and geographic revision.] Nauka, Moscow. 262 pp. Online version: [ ...] .

Last time modified 2016-04-26T10:09:32-07:00 (A.Zinovjev & I.Kadis)