99. EQUISETUM. 17 



roundish or suboblong, transversal, superficial pore. TracheWe bundles 

 enclosed by a common outer and a common inner endodermis (the 

 inner endodermis sometimes wanting, but not in Malayan material).. 

 — ■ Engl. & Prantl, 1. c, fig. 329. 

 § 2. EU-EQUiSETUM. Stomata with their aperture on the level of the 

 epidermis, recognizable by a linear, longitudinal, superficial pore. 

 Tracheide bundles enclosed by a common outer endodermis, or rarely 

 by an own endodermis. (Not in Malaya). 



§ 1. HIPPOCHAETE. 



* 



Ribs of the sheaths rounded. (1) E. ramosissimum. 



Ribs of the sheaths flattened, angular at the sides. (2) E. debile. 



(1) E. rainoiiissiinuni. J>e#f., Milde, Mon. Eq., 428, tab. XXIV; 

 Bk., Fern AIL, 4; E. ramosum, Schleich., Schk., Krypt. Gew., I, tab. 172 b. 



Barren and fertile stems alike, solitary to caespitose, vaiying from 

 short to 3 m. or more long, 1 — 10 mm. - diam., with a large central 

 hollow (Vs — ^3 diam.), grooved, simple or irregularly branched; branches 

 very different in length, few to numerous, simple or branched again; 

 ribs 4 — 26, convex, narrower than the grooves, rough (transversely rugose 

 or verrucose); grooves provided with 2 separate or contiguous series of 

 stomata (each series consisting of 1 — 4 lines of pores). Sheaths loose, 

 distinctly funnel-shaped, relatively long, the teeth deciduous, with a per- 

 sistent, generally triangular-oblong base, the mouth of the sheaths there- 

 fore finally commonly toothed; ribs convex at least in the upper part, 

 often striated with 1 or more fine and shallow furrows, the base passing 

 gradually into a rib of the stem. Spikes to 2V2 cm. long, acute or api- 

 culate. 



Nearly cosmopolitan. 



(2) E. debile, lift., Milde, Mon. Eq., 476, tab. XXVI; Bk., Fern 

 AIL, 5; E. Timorianum, Vaucli., Mon. Prel., 376, tab. X. 



Barren and fertile stems alike, solitary to caespitose, varying from 

 short to long, usually under IV2 m., rarely to 9 m. long, 2 — 15 mm. 

 or niore diam., with a large central hollow (Vs or more diam.), grooved, 

 Fern Allies. 2 



