Notes on District of Columbia Juncaceae

Vol. 31, pp. 45-46

May

^16,1918

PROCEEDINGS

OFTHE

BIOLOGICAL SOCIETY OF WASHINGTON

NOTES ON DISTRICT OF COLUMBIA JUNCACEAE.

BY FREDERICK

V.

COV1LLE AND SIDNEY

^F.

BLAKE.

In the preparation

^of

the manuscript

^of

^{the Juncaceae}

^{for the}

District of

Columbia Local

_Flora, it

has been found

_necessary

to raise

a

_variety of

Juncus

canadensis to specific

rank, and

to

employ new

trinomialsfor

two

_plants

which appear

^to

be

variants ofJuncoides campestre.

The

reasons for these

changes

^{are dis-}

cussed below.

Juncus subcaudatus

_(Engelm.).

.Innnts canadensis var. subcaudatus Engelm. ^{Trans. St. Louis} Acad. Sci.

2^: 474. 1868.

The

distinctivecharacters of thisform, hothinhabit

and

in seed,have been_recognizedsolong that^{it is}surprising that the plant has not _pre- viously been granted ^the specific recognition ^it undoubtedly ^deserves.

J. subcaudatusdiffers from /. canadensisJ.

Gay

^inits

^more

slender,often lax or

decumbent

habit; in its looser inflorescence, with fewer-flowered usually

much

less

numerous

heads on _loosely spreading ^or sometimes erect branches;

and

particularly^initsverydifferent seeds. In J. cana- densis the seeds are 1.3to 1.5

mm.

long, including the ^loose shining whitishtesta,

which

is provided with about ^{30 to} 40

weak

longitudinal ribs onlyveryobscurely,^ifatall,reticulate,

and

isprolonged ^ateach

end

intoappendagesor "tails " which are two-thirds or quite^as long ^as the body^{oftheseed. In J.}subcaudatus the seed, including the testa, ^is 0.7 to 0.9

mm.

_long,

and

the testa, produced ^atthe ends into appendages only one-third ^as long^as theseed body^{or less,} tightlyencloses thedis- tinctly

plumper

^seed

and

isprovided with about ^20to 25 strong longitudi- nalribsconnected by^{distinctcrossbarssothatitssurface}appears^areolate.

In itsseedcharacters./. subcaudatus

makes some

_approach to </". brevi- caudatus(Engelm.)^Fernald.

The

latter,however, has ^{astrictcontracted} inflorescenceoffew-flowered heads,

and

the capsule conspicuouslyexceeds the perianth.

MaterialofJ. subcaudatus isinthe National

Herbarium

from Pennsyl- 14—Pkoc.Biol. Soc.Wash.,Vol.31, 1918. (4">)

46

Proceedings ^{of the} Biological Society of

Washington.

vania to North Carolina. It has been _reported from

Rhode

Islandto Georgia.

Juncoides

campestre bulbosum (Wood).

Luzula_campestris/3. bulbosa

Wood,

^Class

^Book

^{723. 1861.}

Juncoides bulbosum Small, Torreya^{1: 75. 1901.}

Thisisheretakenas

denned

_{by Fernald}

& _Wiegand

in

Rhodora

(15:

40, 42) in 1913. Itis apparently^{the less}

common

formoftheDistrict.

Juncoides

campestre echinatum

(Small).

Juncoidesechinatum Small, Torreya ^{1: 74. 1901.}

Luzula_campestrisvar^. echinataFernald

& Wiegand, Rhodora 15:

40, 42.

1913.

Apparently^the

commoner

formin the District. Distinguished

by

^the usually strongly divergent branches of the inflorescence

and by

^{the fact} thattheperianth-segments conspicuouslyexceed the_capsule.