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1. SELAGINELLA Beanv. 
The only genus, with the characters of the order. 
§ 1. Stem leaves of one kind, many-ranked: scales of the spikes uniform.—EUSELAGINELLA, 
1. S. rupestris (1..) Spring. Stems densely cespitose, prostrate, ascending or 
trailing, much branched, 5 to 30 em. long: leaves appressed-imbricate, linear or 
linear-lanceolate, convex and suleate dorsally: spikes strongly quadrangular, 12 to 
25 mm. long: macrospores abundant.—Granitic rocks, Burnet County (Rererchon) ; 
Chenate Mountains, Presidio County (Nealley), A very variable species. 
§ 2. Stem leaves of two kinds, 4-ranked, spreading in two planes; those of the upper plane 
smaller and more ascending: scales of the spikes uniform.—STACHYGYNANDRUM Baker. 
* Main stems decumbent, mostly annual: leaves flaccid. 
2. S.apus (L.) Spring. Stems 2.5 to 10cm. long, slender, angled on the face: 
leaves of the lower plane spreading above, the lower reflexed, ovate, acute, serru- 
late, not distinctly ciliate; leaves of the upper plane ovate, short cuspidate: spikes 
6 to 12 mm. long, with the scales ovate, acute, membranous, strongly serrulate, 
acutely keeled in the upper half.—Springy places, head of the Seco (Reverchon),. 
The larger 8. Ludoviciana should be looked for in the lowlands of the Gulf border. 
** Stems densely cespitose, rolling into a nest-like ball when dry. 
+ Light green above, straw colored at base below: leaves ending in a long white awn. 
3. S. Pringlei Baker. Stems densely rosulate, the outer 5 to 10 em, long, the 
inner gradually shorter; branchlets crowded, ascending, 2 to 3 mm. wide: leaves 
crowded, those of the lower plane but little larger: spikes short.—Chenate Moun- 
tains, PresidioCounty. This species was erroneously referred to §. cuspidata in Contr. 
U.S. Nat. Herb. I, 60. 
+ Dark green above, reddish brown below: leaves moderately cuspidate or barely 
* pointed. 
4. §. lepidophylla (Hook. & Grey.) Spring. Stems 5 to 10 cm. long, pinnately 
branched to the base, the pinn ascending, subflabellately compound: leaves of 
the lower plane ascending, closely imbricate, obliquely ovate, obtuse, thick, rigid 
minutely ciliate; leaves of the upper plane nearly as long, obtuse: spikes 6 to 12 
min. long, with deltoid acutely-keeled bracts.—Western Texas (Wright), Chenate 
Mountains, Presidio County (Nealley). 
5. &. pilifera A. Braun, Differs from the last mainly in having the primary 
branching varying from flabellate to pinnate, and with leaves cuspidate and serru- 
late.—Reported from Texas by Baker, who attributes its collection to Wright, but 
we have failed to find this species among any of Wright’s collections accessible. As 
itis found on the high plateaus of Mexico, its appearance in our flora is to be 
expected. 
Various species of Lycopodium (L. alopecurioides, L. inundatum, etc.) should be 
looked for in the lowlands of the Gulf borders, as they are’ found in the remaining 
Gulf States as far as Louisiana. 
ISOETACEZ. 
Plant body consisting of a short bilobed or trilobed trunk which 
emits dense tufts of roots and sends up a compact rosette of rush-like 
leaves: sporangia sessile in the axils of the leaves, some containing 
macrospores and others microspores.—Plants submerged or growin gin 
very wet places. 
