448 Transactions. — Botany. 



("Epicrisis Floridearum," p. 493.) 



D. montagneana : " Sunt in magnitudine et ramificationis 

 norma hujus multa, quibus cum D. crassinervia, Mont., con- 

 venire videtui'. Obstat vero quod de microscopicis venis, ad- 

 modum conspicuis in nostra, nullum verbum,habet Montagne. 

 Suam plantam evidenter senilem, et lamina in pluribus ramis 

 derasa forsan hyemalem, cujus in frondibus juvenilibus paucis 

 venae parum conspicuge adessent, credere propensus fuissem, 

 nonnullas tamen, frondes lamina instructas vidit et depinxit ; 

 venasque in his, si adfuissent, ab eo prsetermissas fuisse eo 

 minus assumere fas est, quam jam tunc temporis praesentiam 

 aut defectvim venarum characteres cujusdam momenti in 

 speciebus proximis dignoscendis praebere cognitum fuit." 



The absence of transverse venation in Montagne's plant is 

 evidently, then, the stumbling-block that prevented Agardh 

 from discarding altogether the specific name crassinervia ; but 

 there are no transverse veins microscopic or macroscopic in 

 my specimens, and this at once separates it from D. epigloss^im, 

 D. pliyllo-phora, and D. montagneana, and gives an additional 

 reason for regarding it as the true D. crassinervia. It also 

 differs from them in many other points of habit, size, &c. ; but 

 upon these I need not dwell. From the following descrip- 

 tion it will be seen that the plant must be placed under 

 Agardh's sub-genus Hypoglossum : — 



D. crassinervia, Mont. 



Eoot a small disc. Main stem flat, corticated, costate to 

 the tips, narrowing somewhat towards the disc, originally 

 bordered with a wing 3mm. -4mm. wide, which disappears in 

 the older plants, leaving only the broad costa 2mm. -4mm. 

 Wide. Costa of pinnae and pinnules similar to that of the 

 main stem, and also narrowing somewhat towards the point 

 of insertion. Frond a bright lake-red extremely thin and 

 flaccid, decomposing rapidly but retaining its colour well if 

 dried when quite fresh, 25cm. -40cm. long, general outline 

 linear, oblong-ovate, or broadly elliptical or irregular, as the 

 pinnae and pinnules do not develope in acropetal succession ; 

 irregularly bipinnately or tripinnately compound. Pinnae 

 and pinnules proliferous winged, but giving the appearance of a 

 distichous frond owing to the abrasion of the lamina, costated 

 to the tips, but not otherwise veined. Pinnae 10cm. -15cm. 

 long, pinnules 2cm. -4cm. long, linear-acuminate, bearing pro- 

 liferous sporophylls, which are developed singly on each side of 

 the costa and on both sides of the lamina, Sporophylls 

 3mm.-4mm. long, linear or ovate, slightly stipitate, costate to 

 the tip," but not otherwise veined, microscopically and irregu- 



* The costa is externally evanescent, but the costal cells can be 

 traced to the tip with the microscope. Vide D. linearis. 



