343 

 KEY TO THE HARPIDIOID HYPNA. 



J. A. WHELDON. 



{Continned fro7ti page 248). 



(E) Drepanocladus (C. Mull, pp) Loeske. 



Stems without paraphyllia, tomentum or dilated cortical cells. 

 Branches typically pinnate. Leaves typically falcate -secund, epapillose, 

 singly nerved, nerve usually long, but in a few forms not exceeding 

 mid-leaf, margins entire, cells linear, laxer towards leaf-base, with 

 cells more or less differentiated, forming distinct auricles. Capsule 

 annulate. Inflorescence dioicous. 



1. Nerve very strong, distinctly excurrent (2). Nerve not ex- 

 current (7). 



2. Leaves not sulcate (3). Leaves distinctly sulcate when dry 

 (D. Barbeyi). 



3. Stems regularly pinnate, robust : leaves 3x1 mm. or more (4). 

 Stems irregularly branched (5). 



4. Leaves falcate -secund : stems and branches falcate at apices 

 (D. capillifoliits var. falcatus). Leaves more or less squarrose : at apices 

 erect patent or feebly secund {D. capillifoliits var. squarrosits). 



5. Robust: leaves large, 4-7 mm. long (6). Slender, elongate 

 (15 cm.) subsimple or slightly branched : leaves small, lanceolate, 

 erect patent [D. capillifoliits var. gracilescens) . 



6. Tall (up to 30 cm.), lower branches elongate and stem-like 

 (8 cm.) : leaves erect patent, upper secund (7X1 mm.), median cells 

 15 times as long as broad (D. capillifolius var. laxifolius). Shorter 

 (5-10 cm.), denuded below : stem and branch leaves nearly uniform 

 (5 X '5 mm.) : lamina cells 16-25 times as long as broad (£>. capillifoliits 

 var. angiistifolitis). 



7. Greenish -ye How to golden or brown : basal cells more or less 

 porose : alar cells relatively small and thick-wallcd, forming small 

 rounded projecting distinct yellowish to brownish auricles, or auricles 

 nearly obsolete (8). Yellowish-green to deep green : basal cells scarcely 

 porose : alar cells usually laxer, forming widely triangular more or less 

 decurrent auricles (19). 



8. Auricles very small, not very distinctly defined, or nearly 

 obsolete (9). Auricles distinct (17). 



9. Leaves small (1-2-5 X -7-1 mm.), more shortly acuminate, 

 not rugose : nerve simple or forked (10). Robust : leaves large (3-6 X 

 I -3-1 -5 mm.) : nerve simple, reaching base of the longer slender acumen: 

 leaves lightly striate and subrugose when dry (12). 



10. Nerve simple brownish-purple (65 /li wide), entering acumen : 

 leaves (i*5-2 mm.) : habit of L. intermedia [D. Flageyi). Nerve often 

 forked, reaching little more than mid-leaf (11). 



11. Stem leaves ovate-lanceolate, acuminate: habit of a small 

 D. Sendtneri (D. brevifoliiis) . Stem leaves widely ovate suddenly 

 apiculate-acuminate : habit of a slender S. scorpioides (£>. latijoliiis). 



12. Stems irregularly branched, leaves concave, with a relatively 

 slender nerve, 40-70 /i wide (13). Stems densely pinnately branched, 

 the pinna; incurved: nerve 80 ^i. wide [D. lycopodioides var. americanits). 



13. Slender and scarcely turgid (14). Robust and more or less 

 turgid (15). 



14. Elongate, leaves distant and rather narrower and with longer 

 acumen than the type falcate-secund, resembling a very robust D. 

 Sendtneri [D. lycopodioides f. attenuata). Shorter : leaves closely and 

 julaceously appressed, the stem apices acute and slightly curved {D. 

 lycopodioides var. jiilaceiis). 



1921 Oct. 1 



