156 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
cm. broad, the costa prominent, sparingly clothed below with spreading capillary 
scales like those of the secondary rachis, above scantily short-strigose; segments 20 
or more pairs below the long-acuminate deeply serrate apex, linear-oblong, straight 
or apically subfalcate, short-acuminate, 10 to 15 mm. long, 3 to 3.5 mm. broad (or 
narrower by the curvature of the margins in drying), varying from sessile at the base 
of the pinnule to adnate and slightly decurrent in the outer part; sterile segments 
serrate to sharply and obliquely incised; fertile segments pinnatifid about two-thirds 
the distance to the costule, the lobes cucullate, usually broader than long, rounded, 
often slightly emarginate; costules elevated, those of the fertile segments bearing 
persistent capillary scales below; veins 7 or 8 pairs, those of the sterile segments 
mostly once or twice forked, those of the fertile segments sometimes simple, usually 
once forked, the sorus borne at the end of the distal branch, the other branch evident 
as a short spur immediately below; sori mostly 4 or 5 pairs, occupying the lower two- 
thirds of the segment, about 1 mm. broad; paraphyses numerous, rather long, flaccid, 
light brownish. 
Type in the U. 8S. National Herbarium, no. 690479, collected in the temperate 
mountain region of Chiapas, Mexico, 1864-70, by Dr. A. Ghiesbreght (no. 353). This 
number was determined by Hall! as Dicksoniana sellowiana Hook., a South American 
species, from which it is widely different. More recently Doctor Christ has reported ? 
(as Cibotium wendlandi Mett.) a plant from El Zontehuitz, Chiapas, altitude 2,858 
meters, Munch 104, which may prove to be this species. 
Dicksonia ghiesbreghtii is allied to D. karsteniana, from which it differs especially 
in its narrower segments and simpler venation, as well as in the narrower lobes of the 
segments and in having a rather noticeable covering of stiffish, turgid, short-celled 
hairs upon the costules. 
DOUBTFUL MATERIAL. 
There are at hand also the following specimens whose status can 
not be determined satisfactorily at present: 
1. United States National Herbarium nos. 575152 and 830655, collected from 
“foréts de l’Achiote,’’ Volcano Poas, Costa Rica, altitude 2,200 meters, November, 
1896, by A. Tonduz (no. 10697). This number has been mentioned several times 3 
by Doctor Christ as a species of Cibotium, being referred by him (apparently with 
some doubt) to C. wendlandi, although, as pointed out by the writer recently,‘ it 
really represents a species of Dicksonia. The aspect of these specimens is different 
from that of any North American species and rather strongly suggestive of larger 
states of D. sellowiana from Brazil. Further material from Poas will probably indicate 
the specific distinctness of this form. 
2. United States National Herbarium no. 676144, collected near the summit of the 
Divide, above Camp I, Holcomb’s trail, above El Boquete, Chiriqui, Panama, alti- 
tude about 1,900 meters, by William R. Maxon (no. 5668), March 23, 1911. This, 
which may be a form of D. gigantea, is notable for its narrower and more spreading 
pinnules, blunter and simpler segments, muriculate rachises, etc. Certain individ- 
uals in this locality, which were supposed to be of the same species, had trunks fully 
6 meters high. 
' Hall, Franklin W. Catalogue of a Collection of Ferns made in Southern Mexico, 
mainly at Chiapas, by Dr. A: Ghiesbreght, in the years 1864-70. pp. 10. New Haven, 
Connecticut. 1873. 
? Bull. Herb. Boiss. II. 5: 251. 1905; 5: 734. 1905. (See Contr. U. 8. Nat. Herb. 
16: 57. 1912.) 
3 Bull. Herb. Boiss. II. 5: 734. 1905; 6: 189. 1906; 7: 273. 1907. 
* Contr. U. 8. Nat. Herb. 16: 57. 1912. 
