Studies in the Phytogeny of the Filicales. 
VIII. On Loxsoma and Loxsomopsis. 
BY 
LlttRARV 
NEW YORK 
*-* oT AN ICAL. 
F. O. BOWER. 
With six Figures in the Text. 
OX SOMA Cunninghamii , R. Br., is a Fern which has always com- 
jlv manded attention from the time of its first discovery by Allen Cun¬ 
ningham. 1 Its endemic occurrence in New Zealand, together with its 
peculiarities of structure, marked it out for over half a century as the sole 
living representative of a distinct family of the Loxsomaceae, and indicated 
for it a problematic position in the system. It appeared to be a solitary 
surviving, synthetic type. A relatively primitive position was indicated for 
it in some degree by its habit, and also by its anatomy with solenostelic 
rhizome and undivided leaf-trace, now fully known by the work of Gwynne- 
Vaughan 2 and of McLean Thompson ; 3 by its investiture of hairs, with¬ 
out any flattened scales: but more particularly by the position and 
characters of its sori and sporangia. 
The sorus is strictly marginal in position, with a cup-like indusium 
surrounding the cylindrical receptacle, which bears the sporangia in 
basipetal sequence. These .characters suggested a relationship to the 
Hymenophyllaceae ; but on the other hand the facts would also countenance 
comparison with Thyrsopteris. The sporangia are, however, distinctive 
from either, for they alone among those of gradate Ferns dehisce along a 
median plane, while only a fraction of the oblique annulus is indurated ; the 
rest of it consists of thin-walled cells, which nevertheless are still to be 
recognized as a continuous oblique ring. This endemic New Zealand 
species remained thus for nearly sixty years an isolated type. 
In 1904 a closely related Fern, discovered by Werckle and Brune in 
Costa Rica, was described by Christ under the name of Loxsomopsis costa- 
ricensis , Christ. 4 This discovery was quickly followed by others, viz. Z. 
Lehniannii , Hier, 5 from Ecuador, and L. notabilis , Slosson, collected in 
1 Hooker: Comp, to Bot. Mag., 366, 1S36. 
2 Ann. of Bot., vol. xv, p. 71. 3 Trans. Roy. Soc., Edin., vol. lii, p. 715. 
4 Bull. l’Herbier Boissier, ii, 4, p. 399, tom. 1. 5 Engler’s Jahrb., vol. xxxiv, p. 435, 1904. 
[Annals of Botany, Vol. XXXVII. No. CXLVII. July, 1923.] 
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