21 



Lvs erect, soft, bright g, fewer (12-20) ly somewhat confluent wart*, dark- eol- 



short (4-5' long 1 ); stomata mostly few, ored; microspores 0.028-0.031 mm long, 



near the tip; sporangia nearly orbicular, smoother or slightly papillose. Stone 



pale-spotted, two-thirds or more covered Mt, Ga. 



by the broad velum; microspores 0.39- "^Peripheral bast bundles present. 



0.5 mm thick, with longer and slenderer, I. —Velum partial, 



delicate, generally simple spinules; I: ENGSJIiBtANNI A. Braun, A 1:33. 



microspores 0.026-0.03 mm long. Mass Lvs 25-100, light g, 9-20' long or more, 



(Boott). Synonym: I. Boottii A. Braun with abundant stomata; sporangia ob- 



in litt. long to linear-oblong, unspotted; velum 



Variety MURICATA Engelmann. narrow; ligula elongated from a tri- 



Lvs (15-20) long (6-12'), flaccid, bright angular base; macrospores 0.4-0.52 mm 



g, with very few stomata; sporangium thick, delicately honeycomb-reticulated; 



broadly oval, pale-spotted, about V 2 cov- microspores 0.024-0.028 mm long, gen- 



ered by velum; macrospores 0,4-0.58 mm erally smooth. New England; NY; Mo; 



thick, with shorter and more confluent, 111 



therefore sometimes almost crest-like Variety GXfcACXEXS E, Ex G, Man. ed 



spinules: macrospores slightly rough on 5, 676. 



the edges, 0.028-0.032 mm long. Near Often submerged, lvs 8-12, 9-12' lg; 



Boston, Mass (Boott). Synonym: I. bast-bundles oft Quite sm, or only 2. 



muricata Durien, Soc Bot Fr b 11:101. New England: NX , „ 



I: BOLANDERI E, Am nat 8:214. B2:350, Variety VALXDA E, Ex G, Man, ed 5, 



"Und Z 1:98 SBer mts. 101 Brit Am. 676. ' ft F , 



One of the smaller species, with erect, Lvs 50-100 or even 200, 18-25' lg, 



soft, bright g lvs tapering to a fine keeled on upper side; sporangia Oft 



point, 5-20 or 25 in number, 2-4 Va' long, linear-oblong (4.9" lg), 1-third or oft 



with thin walls and partitions, and gen- y 2 or even 2-third covered by the broad 



erally not many stomata; sporangium ve'nra; macrospores rather smaller, 



broadly oblong, mostly without any 0.32-0.48 mm thick; microspores 0.024- 



spots, with a narrow velum; ligula tri- 0.027 mm lg, spinuloes, Pa; Dela. 



angular; macrospores 0.3-0.4 or rarely Varietv GEORGIAN" A Engelmann. 



0.45 mm thick, marked with minute low Similar to type; lvs few (15), 10-12 



tubercles or warts, rarely confluent to long, rather slender; oval sporangium 



wrinkles; microspores 0.026-0.031 mm with narrow velum; macrospores 0.48- 



long, generally spinulose; rarely, in the 0.56 mm thick; microspores 0.028-0.031 



Rocky Mt form, smooth, deep brown, mm long, smooth. Ga. 



Colo; Ut; Wash. Synonym: I. California I: HOWELI.II Engelmann. 



E, ex G, Man (nomen nudum). Middle-sized, lvs (10-25) bright g 



Section II. — Amphibious, partially emer- (5-8' long) with thick dissepiments; 



ged, submerged only in the earlier per- sporangium oval (l%-2^" long), un- 



iod of their growth or temporarily; sto- spotted, X k-V 2 covered by velum; subu- 



mata always present. late ligula as long as sporangium; ma- 



""Peripheral bast-bundles 0. crospores 0.43-0.48 mm m diam, rough, 



I. — Velum partial. with pronv'nent rounded single or some- 

 X: SACCHASATA Engelmann, Gray's times confluent tubercles. Ore. feyn- 

 Man, ed 5. 676 (1868). onvms: I. nuda Engelm.— I. Underwoodi. 



Plant small, com with a flat, depressed 'fide Heller), 



trunk; lvs subulate, olive-g, spreading, I: 5TTJD A Engelmann. 



10-20 in number, 2-3' long; sporangium Lvs 10-15. bright g, 6-9' long; spor- 



oblong, spotted, with a narrow velum; angia oval, light-brown, attached to base 



ligula triangular; macrospores 0.4-0.47 of lvs by median line only, velum en- 



mm thick, covered with very minute dis- tirely 0;' ligula somewhat triangular; 



tinct or sometimes a little confluent macrospores 0.366-0.4 mm thick, slightly 



warts; microspores papillose, 0.024-0.028 tuberculate, tubercles somewhat conflu- 



mm long. Md Canby). ent. Hood river, Ore (Howell). 



X: H.IFAX&IA Engelmann. IT. — Ve^m complete. 



Lvs 15-30. slender, rather rigid, deen X: "PT.ACCX'DA Shuttleworth, 

 g, 4-8' long, with num stomata: spor- Lvs 10-35, bright g, 15'-2 B long, sub- 

 angia mostly oblong, distinctly brown- merged, floating on the surface, or 

 spotted, 1 -fourth or 1-third covered by wholly emerged; sporangia oval, 2-3' 

 the velum: macrospores o. 45-0. 65 mm long, entirely covered by velum; ma- 

 thick, marked with isolated or anastomo- crospores 0.3-0.42 mm thick, covered 

 sing, iagged crests; microspores more or with many or rarely few, large flattish 

 less tuberculate, 0.028-0.032 mm long, tubercles, distinct, or confluent into la- 

 mm long. Md; (Canby). bvrinthiform wrinkles. Ela. 



II. — Velum complete. Variety SfclGlBA Engelmann. 



X: MELAHOSPORA Engelmann, St. A smaller form with still more slen- 

 Louis ac tr 3:395, note. der. erect, dark g lvs (about 10-15 in 

 One of the smallest species, with a number. 5-6' long). Lake Flint, Fla 

 flat, only slightly bilobed trunk; lvs few (A. P. Garber). 

 (5-10, 2-2V 2 ' long), distichous, slender, Variety CHAPMANI Engelmann. 

 tapering, light g, spreading; sporangium Lvs about 30, floating, 18' long; spor- 

 orbicular or almost obcordate, V 2 -l" lg, angia orbicular; macrospores 0.44-0.55 

 entirely covered by the velum, unspotted; mm thick, almost smooth on upper side; 

 ligula short-triangular, obtuse, or about microspores slightly papillose, 0.027- 

 semi-orbicular; microspores 0.35-0.45 mm 0.03 mm long. Near Mariana, Fla (Chap- 

 in diam, roughened with distinct or rare- man). 



