Hesperostipa spartea
 
Porcupine-Grass

Floret Dissected B

Hudson Bay Regional Park
07-July-2022

The lemma has been split into two pieces and spread apart to reveal the palea. Also, the long, green ovary has been removed from inside the palea. Note the sharp-pointed base of the callus.

The following items are taken from keys in Flora of Saskatchewan, Fascicle 4, Grasses of Saskatchewan by Anna L. Leighton and Vernon L. Harms.  Family Poaceae is first divided into tribes, then the tribes are divided into genera, and the genera divided into species.  However, there are a number of tribes that are very difficult to distinguish morphologically.  These are grouped into a large, artificial tribe I call "Multitribe".  Multitribe is then divided into groups, and each group is then divided into genera.  The answers are in the order you would normally work through the keys.

Stipeae: Answers to key questions leading to this tribe. 
Mature inflorescence, if breaking into units, then the units not as below; NOT [Mature inflorescence breaking into spikelet units consisting of a sessile fertile spikelet, a hairy pedicel with or without a sterile spikelet at tip, and a hairy rachis joint, all arising at the same point (a node) in specialized panicle branches called rames]
Spikelets not as below; sterile florets if present, either located distal to the fertile floret(s) on the rachilla or paired and attached at the base of a single fertile floret, not paired with the upper glume as below; lemma and palea variously textured, enclosing the flower or not; disarticulation usually above the glumes; NOT [Spikelets usually dorsally compressed, appearing 1-flowered but containing 1 fertile floret and 1 sterile floret, the latter attached to the base of fertile floret opposite the upper glume, resembling the upper glume, and together with the upper glume enveloping the fertile floret; lower glumes minute (sometimes absent) to 3/4 as long as upper glumes and typically wrapping most of the way around the pedicel at base; fertile floret seed-like with chartaceous-indurate lemma and palea enclosing flower and fruit; disarticulation below the glumes with rare exceptions]
Spikelets 1 to many-flowered, subtended by a pair of glumes (only 1 on lateral spikelets in Lolium); palea margins enclosed or not; plants of dry or wet habitats; NOT [Spikelets 1-flowered, lacking glumes; margins of the palea tightly enclosed by the lemma margins on female or perfect florets; plants of wetlands, often emergent aquatic]
Inflorescence not as below; if a terminal spike, then the lateral spikelets attached edgewise to the rachis with inner (upper) glume wanting (as in Lolium); NOT [Inflorescence a terminal spike with sessile or subsessile spikelets attached broadside at nodes on opposite sides of the rachis]
Lemmas stiff to indurate, firmer than the glumes, surrounding the palea and often overlapping along the margins, closed at the tip as well as at the base, often pubescent; lemma awns (caducous or wanting in some species) terete and encircled at the base by the closed tip of the lemma; calluses usually pubescent, rarely glabrous; NOT [Lemmas and lemma awns not as above; if lemma indurate and enveloping the floret, then glumes distinctly dorsally compressed and calluses glabrous (as in Milium)]
Lemma awns 1, persistent or caducous; lemmas usually pubescent; NOT [Lemma awns 3, persistent; lemma glabrous]

Hesperostipa: Answers to key questions leading to this genus (in tribe Stipeae). 
Lemma awns 50-225 mm long; lemmas 7-25 mm long; callus 2-6 mm long, sharp-tipped; glumes 15-45 mm long; NOT [Lemma awns 1-32+ mm long; lemmas 1.5-7 mm long; callus to 2 mm long, blunt to pointed but not sharp-tipped; glumes 2.5-13 mm long]

Spartea: Answers to key questions leading to this species (in genus Hesperostipa). 
Lemma pubescence concentrated proximally and extending distally along the margins or in lines between the nerves, the hairs usually brown and about as dense as the callus hairs at least on the lower part of the lemma (becoming less dense distally); lower glumes usually about equal in width to the upper glumes, and long attenuate or with hair-like tip < 1/2 the length of the body; lemma awns stout, strongly geniculate on drying with a terminal segment up to 75 mm long and straight on drying; NOT [Lemma pubescence evenly distributed throughout, the hairs usually white and much less dense than the callus hairs (the lemma hairs may be rubbed off in places on mature florets); lower glumes usually narrower than the upper glumes, distinctly 3-nerved with wide hyaline margins and a long hair-like tip that can be > 1/2 the length of the body (these tips may break off with age); lemma awns slender, weakly geniculate with a terminal segment 40-120 mm long and strongly curling on drying]
Lemmas >= 15 mm long; lemma pubescence extending distally along lemma margins and often also between the nerves; lemma awns 90-190 mm long; glumes >= (22) 29 mm long; lower leaf sheaths usually with ciliate margins; plants 4.5-9 (14) dm high; NOT [Lemmas <= 14 (15) mm long; lemma pubescence extending distally along lemma margins primarily; lemma awns 50-105 mm long; glumes <= 30 mm long; lower leaf sheaths with hyaline margins; plants usually to 6.5 dm high, occasionally taller]