210 



moors. Some prefer wet situations, and the sides of rivers where they 

 are regularly inundated. Two or. three tropical species are epiphytal 

 and grow on trees. They are distributed throughout the temperate 

 and tropical regions of the world and are about equally divided between 

 both hemispheres. 



Plants terrestrial : fronds entire ; spikes single, erect. 



1. 0. nudicaule. 



2. 0. vulgatum. 



3. 0. reticulatum. 

 Plants epiphytal ; fronds palmate : spikes several, pendent. 



4. 0. palmatum. 



1. 0. nudicaule, Linn. fil. — E-ootstock small, descending sheathed 

 with brown scales ; stipites slender, erect J-2 in. 1. ; leaf-blade erect 

 oblong or ovate-oblong, 1-3 in. 1., J-1 in. w., shortly and equally 

 pointed at apex and base, thinly membranous ; veins copiously areolated, 

 the larger series containing a smaller, a distinct vein forming a slender 

 midrib spike single, slender, ^-IJ in. 1., on a slender erect petiole 1-3 

 in. 1., continuous with the stipe -Eat. Fer. N. Am. pi. 81. 0. 

 sarinamense, Eeich. 



Variable in size. A much more slender plant than the two 

 following, with uniformly ovate-oblong leaf -blades, which are the same 

 form at each end, and slightly pointed. It is generally dispersed from 

 the Southern United States to Brasil. 



2. 0. mlgatum, Linn. — Rootstock as thick as cord, creeping under 

 ground, producing buds at intervals which throw out roots and leaves ; 

 stipes 1-2 or 3 in. 1., erect ; leaf-blade j^rd. 1 in. each way, subovate, 

 but variable in shape, acute pointed, the sides rounded at the base and 

 suddenly contracted and shortly extended into the petiole, but not dis- 

 tinctly cordate ; firmly membranous : veins copiously reticulated, with 

 more slender divaricating venules or finer meshes within the larger 

 areolae, no midrib ; spike single, springing erect from the top of the 

 stipe at the base of the leaf -blade, ^rd.-f in. 1,, on a stem 1-2 or 3 in. 

 l.,-Hook. Brit. Ferns, t. 46. Eat. Fer. N. Am. pi. 81. 



Abundant, forming extensive patches often several feet wide, on 

 open slopes and ridges at 5,000 ft. altitude and higher ; mature in 

 December and January. This is found in the same habitats as 

 Botryckium ternatim, under biacken on open moorland. The fronds 

 are one or two from each bud-stock. Distinguished from reticulatum, 

 to which it approaches nearer in the form of the leaf -blade than to 

 nudicaule, by the large patches which it forms, the smaller size, firmer 

 texture, and leaf-blades not cordate at the base. 



The creeping horizontal cord-like rootstocks form a close net-work 

 two or three inches deep under ground, and when the plants are pulled 

 up by hand only the small thickened bud-stock is obtained ; the former 

 must be dug up with some sharp instrument. At a lower elevation 

 plants are found intermediate between this and reticulatum. 



