44 ARKIV FÖR BOTANIK. BAND 1. 



really diiFerent forms, than endeavour to force them into a 

 few unskilfully characterized and dubious species. For the 

 purpose of gaining a scrupulous knowledge of these minute 

 plants, it must be repeated, that only a microscopical exami- 

 nation can afford a useful result. 



I have seen Tr. sphenoides (as it is limited here) from 

 Guadaloupe, collected by Forsström (Herb. Casström, Stock- 

 holm), fig. 22, A — C, and from French Guiana, collected by 

 Sagot, n. 847 (ex parte; the rest of 847 is my Trich. myrio- 

 neuron), fig. 23, A, B and 28, C. Probably belongs here a 

 specimen from Cuba, collected by Wright, n. 1836 (and n. 915, 

 ex parte), fig. 23, C — E. I collected this species in the Bra- 

 zilian state of Matto-Grosso, on trees amongst mosses in the 

 primeval forest called »Poaia» (and intermixed with Tr. punc- 

 tatum), Exped. 1. Regnell., n. 2903 Va; fig. 22, Y)—F. 



9. Trichomanes fontanum n. sp. — Fig. 24 D— F, 

 25 C, and 26. 



This plant, which I collected in South Brazil, is a very 

 minute fern, ranking very near to the preceding as to vena- 

 tion, involucre, marginal hairs, and rather like it as to out- 

 line, but its frond is dark green (gathered in February, the 

 summer), not lobed but simple and entire or slightly waved 

 at the margin, and very minute, the roundish sterile fronds 

 2 — 3 mm each way, the fertile ones 5 — 6 mm long (the elon- 

 gated terminal lobe with the involucre included) and 1,5 — 3 mm 

 broad. The base is of varying shape, as in other species of 

 Didymoglossum, viz. subcordate, ovate, or lanceolate. The 

 apex is generally shaped into a narrow apical lobe, in which 

 the involucre is immersed, like some forms of Tr. sphe- 

 noides. 



The venation is of the same type as in sphenoides, but 

 perhaps a little sparser. Yet, as the frond is more simple 

 and entire, without lobes, I have only found the veins all 

 equal; and simply bearing a single sorus, the frond has only 

 a branchless costa or midrib. The whole plant is likely to 

 be regarded as a diminished form of Tr. sphenoides, from 

 which it is distinguished by the following marks: 



an always much smaller and almost entire frond; 



