MELANTHACE/E FROM THE GENETIC STANDPOINT. 143 
The two monotypic genera, Nietneria and Petrosavia, are placed by . 
Engler* next to Narthecium, though the affinities of the latter are doubtful 
and the former has been placed in the Hæmodoraceæ. Nietneria corymbosa, 
Klotzch & Schomb., occurs in the mountains of British Guiana. Petrosavia 
stellaris, Beccari, is a root-parasite without leaves, found in Borneo. They 
are only remotely related to the present group of genera. E 
The genas Metanarthecium of Maximowiez, containing two species in 
Japan, also resembles Narthecium in certain respects. 
5. XEROPHYLLUM, Michaux. 
. XEROPHYLLUM ASPHODELOIDES, Nutt. 
X. asphodeloides, Nutt. Gen. i. (1818) 235. 
X. setifolium, Michx. Fl. Bor, Am. i. (1803) 211; Ann. Rep. N.J. State Mus. 1910, 
p. 940, pl. 35 (1911). 
Helonias asphodeloides, Linn. Sp. Pl. ed. 2 (1762) 485; Curt. Bot. Mag. (1804) t. 748; 
Lodd. Bot. Cab. iv. (1819) t. 394. 
Dry pine barrens, southern New Jersey to eastern Tennessee and Florida. 
[1 
9. XEROPHYLLUM TENAX, Nutt. 
X. tenax, Nutt. Gen. i. (1818) 255, 
X. setifolium, Lindl. Bot. Reg. (1833) t. 1613, not Michx. 
Helonias tenax, Pursh, Fl. Am. Sept, i. (1814) 243, t. 9. 
On high lands near the Rocky Mountains, British Columbia to Montana, and 
California (Monterey Co.). Abundant, covering hundreds of acres in some 
localities. 
3. XEROPHYLLUM Dovarasi, S. Wats. in Proc. Am. Acad. xiv. (1879) 284. 
? X. setifolium, var., A. Gray, in Proc. Amer. Acad. viii. (1872) 405. 
Oregon, Columbia River (Hall), Montana, Idaho. 
The genus Xerophyllum is remarkably distinct from its nearest relatives, 
Narthecium on the one hand and 77elonias on the other. The three species 
are closely in agreement with each other, the differences being entirely 
quantitative. Like so many Pacific coast species, X. fena is much larger 
than its eastern congener, X. asphodeloides. Lindley, who studied plants 
grown from seed collected by Douglas in the north-west, was “unable to 
detect the slightest mark by which they may be separated,” though his 
figure shows a wider-leaved plant than X. asphodeloides. X. tenax is generally 
much larger and stouter, with broader leaves (4-6 mm.), the leaves of 
X. asphodeloides being very narrow (1-2 mm.). The flowers of X. tenaz are 
also somewhat larger, and the stamens exceed the perianth-segmenís. The 
seeds also are said to differ slightly in shape. It is possible that X. tenax 
is a tetraploid species, though this seems improbable. 
* Nat. Pflanzenfam. T. ii. Abt. v., Liliacem, p. 20 (1887). 
