108 A SYNOPSIS OF THE SPECIES OF ISOETES. 



membranous border decurrent from the dilated base. Sporange 

 small, pale, globose; veil complete. Macrospores middle-sized, 

 furnished with large scattered tubercles. Microspores densely 



spinulose. 



Hab. Marshes of Central France, Boreau! Franchet! 



33. I. olympica, A. Br., Milde Fil. Eur., 285.— Rootstock 

 3-lobed. Habit of I. tenuissima, but leaves more numerous, 

 11-2 in. long, opaque, pale green, furnished with stomata and a 

 few weak accessory bast-bundles. Sporange small, globose, 

 unspotted ; veil partial or nearly complete. Macrospores small, 

 furnished with small tubercles between the ridges and stronger 

 ones over the lower half. Microspores spinulose. 



Hab. Bithynian Olympus, in swamps of the granitic plain, at 

 6000 feet above sea-level, Dr. C. von Fritsch. 



34. I. Welwitschii, A. Br. in Kuhn Fil. Afric, 196.— Root- 

 stock 3-lobed. Leaves 6-15, as firm in texture as in 1. Duriai, 

 2-3 in. long, very slender, pale green, J lin. diam., furnished with 

 stomata and accessory bast-bundles. Sporange small, pale, 

 globose; veil very narrow. Macrospores small, greyish, with 

 small tubercles between the prominent ribs and larger ones over 

 the lower half. Microspores granulated. 



Hab. Angola, in high spongy pastures of the Province of 

 Huilla, at 3800-5500 feet, Wehntsch, 166 ! 



35. I. nigritiana, A. Br. in Kuhn Fil. Afric, 196.— Rootstock 

 3-lobed. Habit of I. setacca. Leaves 12-15, very slender, firm in 

 texture, 6-8 in. long, \ lin. diam. at the middle, pale green, 

 opaque, furnished with stomata and a few weak accessory bast- 

 bundles. Sporange pale, globose, £ in. long ; veil very narrow. 

 Macrospores small, greyish, with a single tubercle between each 

 ridge and several over the lower hemisphere. 



Hab. In the Niger country at Nupe, Barter, 1020 ! 



36. I. Schweinfurthii, A. Br. MSS. — Rootstock 3-lobed. 

 Habit of I. setacea. Leaves 12-30, about a foot long, moderately 

 firm in texture, opaque, tapering to the point, §-$ lin. diam. at 

 the middle, furnished with stomata and accessory bast-bundles. 

 Sporange small, globose ; veil none. Macrospores small, chalk- 

 white, with high ridges and strongly honeycombed all over. 



Hab. Central Africa, in the Kingdom of Diur, S chic e injur th, 

 1962! ° J 



37. I. ^equixoctialis, Welw. ; A. Br. in Kulm Fil. Afric, 195, 

 Rootstock 3-lobed. Habit of I. xctacea. Leaves 6-12, very 

 slender, a foot or more long, | lin. diam, at the middle, opaque, 

 pale green, firm in texture, tapering to the point, furnished with 

 copious stomata and several accessory bast-bundles. Sporange 

 globose, £ in. diam. ; veil partial. Macrospores middle-sized, 

 chalk-white, furnished with strong ridges and prominent tubercles. 

 Microspores densely muricated. 



Hab. Angola, in damp pastures of Pungo Andongo, alt. 

 2400-3800 feet, with Droscm, Dr. Weluitsch, 50 ! 



